Attentional, emotional, and behavioral response toward spiders, scorpions, crabs, and snakes: Do they all scare us?

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Eva Landová, Iveta Štolhoferová, Barbora Vobrubová, Jakub Polák, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2734657/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Nov, 2023 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Spiders evoke significant fear and disgust in many people; such a complex response has been formed throughout human evolution. However, most spiders do not present a serious threat, so the evolutionary explanation is controversial. We suggest that other chelicerates, e.g., scorpions, might have been important in the formation and fixation of the spider-like category. In this eye-tracking study, we checked for some aspects of the attentional, behavioral, and emotional response to the spider, scorpion, snake, and crab stimuli used as task-irrelevant distractors. Results showed that spider-fearful participants were selectively distracted by spiders, but also by crabs which were not consciously rated as fear-eliciting. We hypothesize that spider-fearful participants might have mistaken crabs for spiders based on their shared physical characteristics. Contrary, participants with no fear of spiders were distracted the most by snakes and scorpions. No difference between snake and scorpion distractors was found supporting the notion that scorpions are also prioritized, evolutionary relevant stimuli. We conclude that scorpions are evolutionary fear-relevant stimuli, however, the generalization between scorpions and spiders was not supported in spider-fearful participants. This result might be important for a better understanding of the evolution of spider phobia. Biological sciences/Psychology Biological sciences/Psychology/Human behaviour Figures Figure 1 Figure 2 Figure 3 Introduction Over the course of our evolutionary past, humans have developed several complex adaptations about how to respond to life-threatening stimuli such as various predators [ 1 ], venomous snakes [ 2 ], or enraged conspecifics [ 3 ]. Early detection of these ancestral dangers is often accompanied by a strong emotional response, which further affects the following conscious attention and rapid adaptive behavioral response [ 4 , 5 ]. Evolutionary relevant threatening animal stimuli are thought to activate the fear module [ 6 ], a complex biopsychological system whose concept has been derived from the preparedness theory proposed by Seligman [ 7 ] and elaborated by Mineka and Öhman [ 8 ]. Preparedness theory suggests that quick fear learning and its slow extinction are predominantly associated with those stimuli that posed threat to human ancestors. Numerous studies built upon the preparedness theory and fear module, testing their assumptions [ 9 – 11 ]. In this study, we focus on how fear-relevant animals affect attention during an animal-unrelated task. By far, the most often investigated animal in fear module research is the snake. In her Snake detection theory, Isbell [ 12 ] suggested that the evolution of the primate visual system has been strongly shaped by the need for rapid detection of snakes. A large body of evidence has been found in support of this hypothesis [ 13 – 16 ], although some discussion is being held on its ecological validity [ 17 ]. Several papers showed specific early as well as late attentional changes in brain activity in response to snakes [ 18 – 20 ]. Snakes were also shown to be detected faster than other animals in visual search tasks using an eye-tracking camera [ 21 , 22 ], even in suboptimal visual conditions [ 23 ]. Venomous snakes also evoked elevated psychophysiological responses [ 24 ]. Recently, coevolution between snakes and primates was illustrated in an example of snake venom and resistance to it in primates [ 25 ]. Altogether, common fear and negative attitude toward snakes seem evolutionary well based [ 26 ]. Contrary to that, the origin of fear of spiders remains uncertain despite its relatively large prevalence in the general population. High and exaggerated fear of spiders, arachnophobia, is one of the most common anxiety disorders with a prevalence of 2.7–6.1% [ 27 ] or even 10% [ 28 ]. The majority of spider species have not been seriously dangerous for contemporary humans or their ancestors [29, reviewed in 30]. and thus, the evolutionary explanation of arachnophobia is questionable. Some authors suggest that fear of spiders is driven by contamination-based disgust (reviewed in [ 28 ]). Matchett and Davey [ 31 ] proposed the disease-avoidance model hypothesizing that spider phobia develops based on the disgusting properties of the spider [ 32 , 33 ] and fear of involuntary physical contact with spiders. Davey [ 34 ] suggested that these disgust-relevant properties of the spider had become apparent during the plague pandemics in the Middle Ages. As the etiology of the disease remained unknown, spiders served as a displaced target. In some studies, spiders are viewed as prototypical fear stimuli similar to snakes [ 2 , 35 ], but event-related potential studies comparing attention to spiders, snakes, and other animals showed that the brain potential related to exogenous attention (P1) had the highest amplitude in response to snakes but not spiders, while enhanced attention-related brain activity (LPP) was found in response to both snakes and spiders [ 18 , 36 ]. Similarly, in a visual search task, adult participants detected snakes more quickly or accurately than spiders [ 21 , 22 ]. In conclusion, the human reaction to snakes and spiders does not seem directly comparable. Another hypothesis suggests that fear and disgust of spiders is a generalization of fear and disgust of other disease-carrying invertebrates [ 33 ]. On the one hand, He et al. [ 37 ] in their ERP study showed that there was no difference in attentional brain activation among spiders, wasps, bumblebees, or beetle stimuli, which pointed out to a high level of attentional generalization among stimuli. On the other hand, spiders and morphologically similar chelicerates are perceived highly specifically and differently compared to other invertebrates, including insects [ 30 , 32 , 33 ]. Generally, spiders are perceived very specifically in subjective emotional evaluations and people do not generalize them to other arthropods, whereas in experimental measures of attentional response, the degree of generalization varies and requires further investigation. A similar hypothesis suggesting that fear of spiders is a generalized fear of scorpions is also not supported by subjectively perceived fear or disgust. Scorpions from this perspective form a separate, albeit sister category to spiders [ 30 , 33 ]. Rudolfová et al. [ 38 ] investigated spontaneous attentional bias toward scorpions and spiders in a cross-cultural eye-tracking experiment. Higher attentional bias for scorpions as opposed to spiders was demonstrated in Somalis and a similar albeit smaller bias in Czechs. In the following eye-tracking study, we measured attentional, behavioral, and emotional reactions to spiders, crabs, and scorpions to uncover a pattern of generalization among these stimuli. For the investigation of early and late attentional response, an eye-tracking method is often combined with measuring reaction time by pressing a key or touching a screen. Several designs are usually employed: a visual search [ 2 ], an inattentional blindness paradigm task [ 35 ], or a flicker paradigm task [ 39 ]. In this study, the investigated animal was used as a task-irrelevant distractor. A similar design was previously used, for example, by Zsidó et al. [ 40 ]. The participants were instructed to find numbers on a screen where a snake was also displayed, and the task-solving time was measured. We wanted to know if the distraction of attention by task-irrelevant animals was specific to the spider stimuli compared to other invertebrates (scorpions and crabs) in spider-fearful versus non-fearful participants. The results were further compared with those triggered by the snake, the prototypical evolutionary relevant threatening stimulus. Specifically, we focused on three types of responses that should be influenced by sensitivity to fear of spiders: (1) The attentional response – participants with high fear of spiders will be distracted specifically by the spider images leading to higher latency in fixating the true target in both the within-subject (compared to other animal stimuli) and between-subject comparison (compared to participants with low fear of spiders). (2) The behavioral response – the same effect would be manifested by a longer reaction time (pressing the response button). (3) The emotional response – the higher the fear of the distractor animal, the wider the mean and maximal pupil size of the participant while watching the presentation slide. We predict the same direction although of a smaller magnitude for the disgust emotional response. Results Attentional response The attentional response differed between the participants and between the target positions within the participant (both incorporated as random factors), however, it was not significantly affected by any of the investigated explanatory variables. Hence, in the model for latency in fixating the true target for the first time, all fixed effects were successively reduced: Gender – Age interaction (F = 0.05, p = 0.832), Animal category – SPQ score interaction (F = 2.16, p = 0.091), Animal category (F = 0.55, p = 0.650), Gender (F = 1.53, p = 0.219), SPQ score (F = 3.56, p = 0.062), and Age (F = 6.72, p = 0.011). Behavioral response As hypothesized, the latency of finding the true target was greater for participants with higher SPQ scores in images with the spider and crab distractors but not with scorpion or snake distractors. Neither the participant’s gender, age, nor their interaction affected the reaction time hence these effects were successively reduced: Gender – Age interaction (F = 0.10, p = 0.754), Gender (F = 1.18, p = 0.281), and Age (F = 3.34, p = 0.070). In contrast, the animal category, SPQ score, and their interaction were kept in the final model: Animal (F = 3.66, p = 0.012), SPQ score (F = 5.57, p = 0.020), and Animal – SPQ score interaction (F = 4.95, p = 0.002). The animal categories intercepts (estimated means for SPQ score = 0) are 6.86 for the crab, 6.95 for the scorpion, 6.96 for the snake, and 6.89 for the spider. The intercept for the crab is significantly lower than the one for the snake and scorpion (p-values < 0.004). As predicted, the reaction time for the spider is higher with a higher SPQ score (p = 0.002). This holds also for the crab (p = 0.007), but not the scorpion (p = 0.135) or snake (p = 0.158). The slope coefficient for the spider is therefore significantly different from the one for the scorpion (p = 0.005) and snake (p = 0.003) but not for the crab (p = 0.453). Note that all reported estimates were computed from natural logarithm-transformed values. The results are shown in Table 1 and Fig. 1 . Table 1 Behavioral response – results of the model for reaction time. For participants with low fear of spiders, reaction time was the largest for snake and scorpion distractors. Sensitivity to fear of spiders affected only reaction time for spider and crab distractors. Hence we found the greatest difference in reaction times between spider-scorpion and spider-snake in participants with various levels of spider fear. Est – an estimate of the intercept/coefficient/contrast, 95% CI – 95% confidence interval, t – t-value, p – p-value, p-values < 0.0083 are in bold. Note that all estimates were computed from natural logarithm-transformed values. Intercept SPQ score coefficient Level / Contrast Est (95% CI) t p Est (95% CI) t p Crab 6.86 (6.75; 6.97) - - 0.01 (0.003; 0.02) 2.74 0.007 Scorpion 6.95 (6.84; 7.06) - - 0.006 (-0.002; 0.01) 1.51 0.135 Snake 6.96 (6.85; 7.07) - - 0.005 (-0.002; 0.01) 1.42 0.158 Spider 6.89 (6.78; 7.00) - - 0.01 (0.004; 0.02) 3.19 0.002 Crab – Scorpion -0.09 -2.88 0.004 0.005 2.19 0.029 Crab – Snake -0.10 -3.08 0.002 0.005 2.34 0.019 Crab – Spider -0.03 -0.93 0.351 -0.002 -0.80 0.424 Scorpion – Snake -0.01 -0.19 0.846 0.0003 0.15 0.879 Scorpion – Spider 0.06 1.95 0.051 -0.006 -2.99 0.003 Snake – Spider 0.07 2.14 0.032 -0.007 -3.14 0.002 Emotional response Regarding the pupil metrics, we found that participants’ maximal pupil size was larger when the animal distractor was rated as more fear-eliciting. Contrary to that, no effect of fear on mean pupil size nor of disgust on either response was found. Results of the models for trial maximal pupil size: Fear – F = 10.16, p = 0.001, intercept = 993.25, Fear coefficient = 3.054; Disgust – F = 6.15, p = 0.013. Results of the models for trial mean pupil size: Fear – F = 6.10, p = 0.014; Disgust – F = 3.71, p = 0.054. Results of image ratings according to elicited fear and disgust are shown in Fig. 2 a and 2 b, respectively. Results of FAs for fear and disgust both revealed a simple structure of four factors with Factor 1 loaded by spider ratings, Factor 2 by snake, Factor 3 by crab, and Factor 4 by scorpion ratings. The rating of the antelope did not correlate with any of the factors. Detailed results of FAs are shown in Supplementary Table S1 . In successive modeling, the effect of some of the tested variables (SPQ score, DS-R score, Gender, Age, and Gender – Age interaction) proved significant only in a few cases. Spiders were rated as more fear-eliciting by participants with a higher SPQ score (Factor 1 of Fear FA: SPQ score – F = 86.56, p < 0.001; intercept=-1.150, SPQ score coefficient = 0.092). Similarly, they were rated as more disgust-eliciting by those with a higher SPQ and DS-R score (Factor 1 of Disgust FA: SPQ score – F = 104.95, p < 0.001; DS-R score – F = 27.15, p < 0.001; intercept=-1.702, SPQ score coefficient = 0.092, DS-R score coefficient = 0.012). On the other hand, snakes were rated as more fear-eliciting by participants with a lower SPQ and higher DS-R score (Factor 2 of Fear FA: SPQ score – F = 9.42, p = 0.003; DS-R score – F = 13.48, p < 0.001; intercept=-0.451, SPQ score coefficient=-0.048, DS-R score coefficient = 0.022) and as more disgust-eliciting by people with a higher DS-R score (Factor 2 of Disgust FA: DS-R score – F = 15.55, p < 0.001; intercept=-1.140, DS-R score coefficient = 0.024). The rating of spiders or snakes was not affected by the participant’s gender, age, or their interaction. Neither the fear nor disgust rating of crabs was affected by any of the investigated variables. The disgust rating of scorpions seemed to be affected by the participant’s gender-age interaction but the effect disappeared when an insignificant term (DS-R score) was reduced from the model. The effect of SPQ and DS-R scores on factor scores (rating of images) is shown in Fig. 2 c and 2 d, respectively. Detailed results of modeling are shown in Supplementary Table S2. Discussion We found no difference in the attentional but a large difference in the behavioral response of spider-fearful participants to images with spider distractors. As predicted, spider-fearful participants reacted slower when there was a spider distractor compared to snake and scorpion distractors. Their response was also slower compared to the control group of non-fearful participants. Concerning our original predictions, the results of the pupillometric models were inconclusive. Ratings of images confirmed that the SPQ score well described participants’ subjective perception of spiders. Attentional response We hypothesized that participants with high fear of spiders would show higher latency in fixating the true target both compared to other animal stimuli and to participants with low fear of spiders. However, we found no such difference as neither the SPQ score nor the animal image proved to have a significant effect on the latency of the true target's first fixation. Fear-eliciting or threatening stimuli have long been hypothesized to capture human attention. This was illustrated, for example, by Lundqvist & Öhman [ 41 ] or Yorzinski et al. [ 1 ]. Originally, two mechanisms behind this phenomenon were suggested. It could be that fear-eliciting stimuli attract the participant’s attention more easily, or that fear-eliciting stimuli hold the participant’s attention longer (see for example [ 42 ]). In recent years, a consensus seemed more inclined towards the latter mechanism [ 43 , 44 ], however, a last-year meta-analysis suggests that both mechanisms can be relevant [ 45 ]. Our results seem to support this hypothesis as well, although we could not test it directly, because the central placement of animal distractors led to zero latency of the first gaze on the animal in all cases. However, in the analysis of true target latencies, we found no effect of animal and SPQ score for the first gaze but a clear effect for the conscious reaction. This is in support of the hypothesis of fear-eliciting stimuli holding attention. Behavioral response As we predicted, the spider-fearful participants’ behavioral response was slower in comparison to non-fearful participants, most probably because they were distracted by the spider images. Importantly, spider-fearful participants were specifically distracted by spider stimuli and not by scorpions or snakes (non-significant SPQ score coefficients, see Table 1 and Fig. 1 ). It has been previously shown that emotions can modulate attention toward a stimulus and facilitate its detection. In a visual search task, Soares et al. [ 44 ] reported that participants found the animal they were afraid of faster than a non-feared but fear-relevant animal. Specifically, spider-fearful participants found spiders faster than snakes and conversely, snake-fearful participants found snakes faster than spiders. Flykt et al. [ 46 ] additionally found that fearful participants pressed the response button harder when the target animal was their specifically feared animal. Even when the feared animal is not the target, it can affect attention. Miltner et al. [ 47 ] found that the presence of task-irrelevant spider distracters slowed the detection of mushroom targets in spider-fearful participants. Our results, therefore, are in agreement with these studies. In this study, we placed the distractor stimuli in the center of the slide and started a new trial only when the participant’s gaze was fixed on the center. Consequently, the participants were aware that one of four animals would soon appear in the center of their visual field. While non-fearful participants did not differentiate between the animals in a way that would affect their “success” in solving the task, spider-fearful participants were selectively affected by spider and crab distractors. This suggests that spider-fearful participants were alert and anticipated the appearance of frightening stimuli. The importance of expectations was previously investigated by Devue et al. [ 48 ] who showed that spider-fearful participants performed poorly in trials with potential spider stimuli but similarly well as the control group when they knew no spider could be expected. Higher alertness when potentially dangerous stimuli are suspected to appear is crucial for the quick activation of an appropriate physiological and behavioral response. Even though high fear of spiders and/or arachnophobia might not be adaptive themselves and are also often consciously considered “nonsensical”, they activate highly adaptive pathways. Surprisingly, although crabs were not subjectively rated as fear- or disgust-eliciting by the spider-fearful participants, they distracted them similarly to spiders. We account for this to the high morphological similarity between crabs and spiders (specifically those selected here as stimuli) which made them easy to be confused by just a glance. From an adaptive point of view, the threshold for what is and what is not a feared stimulus has to change to secure as few false-negative responses (overlooked real signals) as possible when the participant’s attention is directed toward the animal-unrelated task. This, however, can be only done at the expense of false positives (responses to incorrect stimuli). Still, human attention is very fine-tuned for the spider stimuli because scorpions – similar in appearance and biologically close relatives to spiders – did not affect the success of solving the task. A similar result was also shown by New & German [ 35 ] where participants’ responses to spiders and house flies differed in an inattentional blindness task. Interestingly, the scorpion distractors’ effect on the behavioral response did not resemble the effect of spider but rather snake distractors in our dataset. This was quite surprising because snakes have long been considered a special fear stimulus. This notion was supported by several studies (see Introduction) including the eye-tracking ones that showed faster or more accurate detection of snakes (e.g., see [ 2 ]). Later, this view was questioned. It was pointed out that snake detection could have been facilitated simply because they were compared to flowers and mushrooms and not to other animals [ 49 ]. Later again though, the snake’s specificity was confirmed with regards to its distractor properties or when detection took place under challenging setups [ 5 , 22 ]. To the best of our knowledge, the current study is the first one that utilized scorpions as distractor stimuli and compared them to snakes. For participants with low fear of spiders (i.e., the general population), both snakes and scorpions triggered a behavioral response more than the control, fear-irrelevant stimulus – the crab. This supports the hypothesis of the scorpion as the evolutionary fear-relevant stimulus similar to the snake (see [ 30 ] for details). However, the distractor effect of crabs increased with the participant’s SPQ score inevitably influencing the estimated crab-snake and crab-scorpion differences. Although we find the similarity between snakes and scorpions highly interesting, more research is certainly needed. Nonetheless, it seems that two types of generalization might occur: (1) Either the generalization is based on function, and in this case, associated emotions seem adaptive (i.e., both snakes and scorpions are objectively fear-relevant, therefore a fear-mediated behavioral response is generally advantageous). (2) Alternatively, the generalization is based on physical features (as we suspect was the case for spiders and crabs) which may be advantageous, disadvantageous, or neither of those depending on the situation. It is worth pointing out, though, that from the evolutionary perspective, it is also adaptive to allow some level of mistakes [ 50 ]. Emotional response Lastly, we predicted that the participants’ mean and maximal pupil size would be wider when watching the presentation slide with subjectively more feared animal distractors. We found this effect for the maximal but not the mean pupil size. Further, we did not find any effect of perceived disgust on maximal or mean pupil size. It is generally agreed upon that emotional stimuli affect pupil diameter. Both positive and negative emotional stimuli are usually associated with pupil dilation [ 51 ], however, pupil constriction was also noted in some cases. Specifically, pupil constriction was usually found in studies focusing on disgust [ 52 ], which involves the activation of the parasympathetic nervous system [ 53 ]. On the contrary, fear elicits a sympathetic activation, leading to pupil dilation [ 54 ]. In this regard, the spider is a particular stimulus because it evokes both strong fear and disgust, even though fear is usually stronger [ 33 ]; see Fig. 2 a,b). Additionally, it was also shown that pupil dilation increased with a cognitive effort to solve the task. Emotions and cognition can also interact [ 55 ]. In other words, pupil dilation might be the result of several processes and the extent to which each may affect the pupil diameter remains unclear. In this study, we mainly focused on the attentional and behavioral response and pupillometry was rather supplemental, hence the feasibility of some analyses was limited. Additional cautiousness should be executed when interpreting the results because while EyeLink1000 offers pupillometric characteristics, its primary purpose is different. Based on the analysis of image ratings, all images of one type of animal were perceived similarly to each other but as distinct from images of different types of animals. This confirmed that the images were appropriately selected to represent one category and that their grouping into one factor of four levels in statistical modeling was justified. Unsurprisingly but importantly, we also confirmed that participants with a higher SPQ score rated spiders as more fear-eliciting and disgust-eliciting than participants with a lower SPQ score (see Fig. 2 ). This means that a subjective animal rating, a semi-objective SPQ score, and an objective behavioral response are in good concordance and give similar results. In research on the effect of fear elicited by spiders, participants are often divided into two groups which represent two extremes, meaning participants with medium fear or ambiguous emotions (the middle of the scale) are not represented [e.g., 49]. This approach has several advantages, e.g., thanks to the higher difference between the participants, smaller effects can be detected. However, we find relatively even coverage along the whole SPQ scale useful (see, Figs. 1 and 2 c), as well, since it allows us to access the value of behavioral response for any SPQ score (within the included range). We further found that fear of snakes declined with higher SPQ scores (Fig. 2 c). This means that, in our sample, participants who were not afraid of spiders tended to fear snakes more than spider-fearful participants. However, we do not think that this result should be generalized to the population level as it is most probably a by-product of the experimental design (see also [ 28 ]). On the one hand, a high fear rating of snake stimuli should be expected since they were all highly venomous vipers [ 10 , 24 , 56 ]. On the other hand, to spider-fearful participants, spiders are the most salient stimuli no matter the objective dangerousness of others and therefore snakes are rated as less frightening in comparison. Combined, this led to spider-fearful participants being seemingly less likely to fear snakes than the control group. Our explanation is also supported by the frequency of self-reported fear of snakes (yes or no answer to the question: “Are you afraid of snakes more than you consider usual?”). Ten (out of 55) participants from the control group and 13 (out of 50) spider-fearful participants reported being (also) afraid of snakes – a rather similar proportion. Finally, we found that fear of snakes and disgust of spiders and snakes increased with an increasing DS-R score, but the relationship was rather weak (Fig. 2 d). This is in concordance with Arrindell et al. [ 57 ] who also found that disgust sensitivity held only little predictive value about animal fears. Conclusions In this study, we replicated the general experimental design of several previous studies (i.e., the task-irrelevant distractor design; [ 40 , 43 , 47 ]) and found comparable results. However, we also modified the design in numerous important and new ways. First, we recruited participants covering quite evenly almost the full range of the SPQ scale. Second, we used rather large animal images (the distractors) and placed them in the center of the visual field to ensure that participants would gaze at them and enhance the potential distractor effect. Third, we added two new uninvestigated animal stimuli – a crab and a scorpion. Interestingly, the effect of these two distractors proved to be very different from each other – while the effect of the crab quite closely resembled the effect of the spider distractor, the scorpion was more similar to the snake distractor. We hypothesize that spider-fearful participants might have mistaken the crab for a spider because of their high morphological similarity in this stimulus set. In other words, spider-fearful participants generalized their reactions from spiders to crabs based on their shared physical characteristics. Contrary, participants with no fear of spiders were distracted the most by snakes and scorpions. No difference between snake and scorpion distractors was found supporting the notion that scorpions are also prioritized, evolutionary relevant stimuli. To conclude, subjectively feared spiders distracted participants from solving the task to a greater extent than objectively more fear-relevant snakes and scorpions. This supports the view of emotions as an important mediator in behavioral and physiological responses. Methods Participants A total number of 114 participants were originally recruited for the experiment. Of these, 50 participants were undergraduate Czech or Erasmus students that participated for course credit in Ethology and sociobiology course. The remaining 64 participants were recruited from our database of Czech research volunteers based on their scores on the Spider Questionnaire (SPQ, [ 58 ]). Seven participants finished the eye-tracking experiment but chose not to follow through with the image rating (two participants) or completion of the questionnaires (five participants), hence their data were excluded from the analyses. Due to technical difficulties during the eye-tracking data extraction, the data of two additional participants had to be excluded. Therefore, the final sample consisted of 105 participants, 84 women, and 21 men (mean age 25.70 years, range 18–49). Based on their SPQ scores, 55 participants (38 women) had none to moderate fear of spiders (SPQ < 16), while the remaining 50 participants (46 women) had high or very high fear of spiders (SPQ ≥ 16; [ 28 ]). All the participants had a normal or corrected-to-normal vision. Stimuli Each eye-tracking stimulus slide (1920 x 1080 pixels) was a color image of an animal (the distractor) surrounded by 19 dots (false targets) and 1 square (true target) placed on a neutral 20% grey background (see Fig. 3 ). The animal images were sourced from the internet or our database. Criteria for the selection were good resolution of the image, full-body depiction of the animal, and “neutral” body posture. The animal’s original background was cut off and it was placed and sized to fit into the central area of approx. 640 x 540 px. Animal images were of four categories – crabs, scorpions, snakes, and spiders – each represented by five different species. Dots had a diameter of 29 px and the side length of the squares was 26 px making the shapes comparable in size (their area, as well as width and height); all dots and squares were black. They were placed in a 6 by 4 grid with four central positions left out for the animal image. Target positions were of five types (levels) based on their distance from the center. Positions 3, 4, 17, and 18 were closest to the center while positions 1, 6, 15, and 20 were the most distant (see Fig. 3 b). A total of 20 unique experimental slides were created using each combination of the animal category and true target position level just once. Additionally, images of antelopes in the same layout were used to create five practice stimuli. For the eye-tracking analysis, 21 unique areas of interest (AOI) were defined. In the center, there was the animal AOI (640 x 540 px in size). Surrounding each of the 20 grid positions, there were the dot 01–20 AOIs (each 320 x 270 px in size). The AOIs did not overlap and covered the whole slide (see Fig. 3 b). Procedure First, each participant was briefed about the subsequent tasks and gave written consent for his/her participation in the research. The eye-tracking experiment followed. Then, they were instructed to rate the presented stimuli based on the level of elicited fear and disgust. Lastly, they completed two questionnaires: the Spider Questionnaire (SPQ; Czech translation by Polák et al. [ 28 ]) and the Disgust Scale-Revised (DS-R; Czech translation by Polák et al. [ 59 ]). If the participants already completed these questionnaires as a part of previous research (as was the case for all non-student and some student participants), this last step was skipped. All instructions and questionnaires were given in Czech to Czech and Slovak participants and in English to Erasmus student participants (originally from 8 other European countries). Eye-tracking Eye movements were recorded using the EyeLink1000 eye-tracking device; for measuring the reaction times, participants answered using a response box. The participants were seated in front of a 19-inch screen (Full HD resolution, refresh rate 60 Hz) and their head was fixed using a chinrest at a distance of 70 cm from the screen. In the beginning, they answered four questions: age, gender, handedness, and country of origin. Next, the device was calibrated using a standard nine-point calibration procedure, involving the fixation of ten target crosses presented on the computer screen positioned on a three-by-three grid (the first and last target cross was presented in the center). The calibration was subsequently validated with the average allowed error ≤ 0.5° and maximally allowed error ≤ 1° of the visual angle. If the error was higher, the device was adjusted, and calibration and validation were repeated. After successful validation, the experimental task was explained in detail. Participants were instructed to find the square as fast as possible, signal the finding by pressing any button of the response box, and keep their gaze on the square until the whole stimulus slide disappeared. Slides with stimuli presented for 5 seconds (trial) alternated with slides presenting a target cross in the center; the next stimulus slide was presented only after the participant fixated on the target cross. Firstly, five practice stimuli were presented to the participants to get familiar with the response box and the task. Following the practice stimuli, they were offered an opportunity to ask questions. Next, all 20 stimuli were presented in two series, each time in a random order (different for each participant). In total, the experiment consisted of 5 practice trials and 40 experimental trials. The experimental setup was designed using the SR-Research Experiment Builder. Using the DataViewer (SR-Research), we extracted the following variables. For the whole trial: reaction time (RT), trial dwell time, trial fixation count, median fixation duration, blink count, minimal pupil size, maximal pupil size, mean pupil size, saccade count, the total number of visited areas of interest, and sequence of visited areas of interest. For each area of interest (AOI), we additionally extracted AOI dwell time, AOI fixation count, and AOI latency of the first, second, and third fixation. Rating of images Participants rated 21 animal images in total – 20 experimental images and one image of an antelope used in the practice trial. We uploaded the images to a special web application available at www.krasazvirat.cz . Each image was rated on perceived fear and disgust on a seven-point Likert scale (1 corresponded to no fear/disgust, 7 corresponded to very strong fear/disgust). The animals were rated on both emotions at once, and the order of the images was random and different for each participant. Before the rating, each participant filled in a short questionnaire regarding their age, gender, type, and level of education, and whether they considered themselves to be afraid of any animal(s) more than they perceived as usual. Statistical Analysis Firstly, we analyzed data accessed from the eye-tracking experiment; only data from experimental trials were analyzed. We used linear mixed-effects models (LMM) as implemented in the software RStudio [ 60 ], package nlme. In all models, we used the participant’s ID and target position (5 levels, see Fig. 3 b) within the participant’s ID as the random effect. To test our attention and behavioral response-related hypotheses, we successively built models with latency in fixating the true target for the first time and the reaction time as response variables, and the Animal category, SPQ score, and Animal category – SPQ score interaction as fixed effects. We also checked for the effect of Gender, Age, and Gender – Age interaction. As neither of the response variables had a normal distribution, we used a natural logarithm transformation. In the emotional response set of models, mean and maximal pupil size were response variables, while fear and disgust respectively were used as fixed effects and the participant’s ID was used as a random effect. Fixed effects that did not prove significant were successively reduced. To avoid false-positive effects as a result of testing six variables from one dataset, we set α = 0.0083 (Bonferroni correction). Secondly, we analyzed the rating of images. To avoid multiple testing, we performed factor analysis (FA) separately for fear and disgust rating. We employed the principal component method, extracted four factors, and used the Varimax normalized rotation. For each factor, we extracted factor scores and hence defined eight new variables (factors). We used linear models (LM) as implemented in RStudio, to test the effect of SPQ score and DS-R score, as well as Gender, Age, and Gender – Age interaction on the factor scores (participants’ rating of images, eight models in total). Variables and their interactions that did not prove significant were successively reduced. We again implemented a Bonferroni correction and set α = 0.00625 to avoid reporting false-positive effects. Ethical note All experimental protocols were approved by the Ethics Commission of the National Institute of Mental Health (approval no. 117/18, granted on 28 March 2018). The authors also confirm that all experiments were performed in accordance with relevant guidelines and regulations (such as the Declaration of Helsinki). Written informed consent was obtained from all participants included in the study. Declarations Data Availability Statement All data generated or analyzed during this study are included in the Supplementary Information files (Supplementary Table S3). For stimuli slides, please contact the corresponding author. Acknowledgments We would like to thank Ms. Lilit Farsiyan for her support with data collection and all our volunteers who kindly agreed to take part in this research. This project has been supported by the Czech Scientific Foundation (GAČR), project No. 19-07164S, awarded to EL. Author Contributions Conceptualization: DF, EL, SR; data curation: IŠ, BV; formal analysis: IŠ, DF; funding acquisition: EL; investigation: IŠ, BV, KS; methodology: SR VB, MJ; project administration: MJ; supervision: El, DF; writing – original draft: IŠ, EL, JP. All authors have read and agreed to the published version of the manuscript. Additional Information Competing Interests Statement: The authors declare no competing interests. References Yorzinski, J. L., Penkunas, M. J., Platt, M. L. & Coss, R. G. Dangerous animals capture and maintain attention in humans. Evol. Psychol. 12, 534–548 (2014). Öhman, A., Flykt, A. & Esteves, F. Emotion drives attention: detecting the snake in the grass. J. Exp. Psychol. Gen. 130, 466–478 (2001). Fox, E., Russo, R. & Dutton, K. Attentional bias for threat: Evidence for delayed disengagement from emotional faces. Cognition Emotion 16, 355–379 (2002). Öhman, A. & Mineka, S. The malicious serpent: Snakes as a prototypical stimulus for an evolved module of fear. Curr. Dir. Psychol. Sci. 12, 5–9 (2003). Flykt, A. Preparedness for action: Responding to the snake in the grass. Am. J. Psychol. 119, 29–43 (2006). Öhman, A. & Mineka, S. (2001). Fears, phobias, and preparedness: toward an evolved module of fear and fear learning. Psychol. Rev. 108, 483–522. Seligman, M. E. Phobias and preparedness. Behav. Ther. 2, 307–320. Mineka, S. & Öhman, A. Phobias and preparedness: The selective, automatic, and encapsulated nature of fear. Biol. Psychiat. 52, 927–937 (2002). Prokop, P., Tolarovičová, A., Camerik, A. M. & Peterková, V. High school students’ attitudes towards spiders: A cross-cultural comparison. Int. J. Sci. Educ. 32, 1665–1688 (2010). Rádlová, S. et al . Snakes represent emotionally salient stimuli that may evoke both fear and disgust. Front. Psychol. 10, 1085; 10.3389/fpsyg.2019.01085 (2019). Landová, E. et al . 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Environ. 763, 143045; 10.1016/j.scitotenv.2020.143045 (2021). Oosterink, F. M., De Jongh, A. & Hoogstraten, J. Prevalence of dental fear and phobia relative to other fear and phobia subtypes. Eur. J. Oral. Sci. 117, 135–143 (2009). Polák, J. et al . Measuring fear evoked by the scariest animal: Czech versions of the Spider Questionnaire and Spider Phobia Beliefs Questionnaire. BMC Psychiatry 22, 18; 10.1186/s12888-021-03672-7 (2022). Hauke, T. J. & Herzig, V. Dangerous arachnids—Fake news or reality?. Toxicon 138, 173–183 (2017). Frynta, D. et al. Emotions triggered by live arthropods shed light on spider phobia. Sci. Rep. 11, 22268; 10.1038/s41598-021-01325-z (2021). Matchett, G. & Davey, G. C. A test of a disease-avoidance model of animal phobias. Behav. Res. Ther. 29, 91–94 (1991). Gerdes, A. B., Uhl, G. & Alpers, G. W. Spiders are special: fear and disgust evoked by pictures of arthropods. Evol. Hum. Behav. 30, 66–73 (2009). Landová, E. et al . Specificity of spiders among fear-and disgust-eliciting arthropods: Spiders are special, but phobics not so much. Plos One 16, e0257726; 10.1371/journal.pone.0257726 (2021). Davey, G. C. The" disgusting" spider: The role of disease and illness in the perpetuation of fear of spiders. Soc. Anim. 2, 17–25 (1994). New, J. J. & German, T. C. Spiders at the cocktail party: An ancestral threat that surmounts inattentional blindness. Evol. Hum. Behav. 36, 165–173 (2015). Soares, S. C. et al . Exogenous attention to fear: Differential behavioral and neural responses to snakes and spiders. Neuropsychologia 99, 139–147 (2017). He, H., Kubo, K. & Kawai, N. Spiders do not evoke greater early posterior negativity in the event-related potential as snakes. Neuroreport 25, 1049–1053 (2014). Rudolfová, V. et al . Do spiders ride on the fear of scorpions? A cross-cultural eye tracking study. Animals 12, 3466; 10.3390/ani12243466 (2022). Kawai, N. & Qiu, H. Humans detect snakes more accurately and quickly than other animals under natural visual scenes: a flicker paradigm study. Cognition Emotion 34, 614–620 (2020). Zsidó, A. N., Bali, C., Kocsor, F. & Hout, M. C. Task-irrelevant threatening information is harder to ignore than other valences. Emotion 224, 103523 (2022). Lundqvist, D. & Ohman, A. Emotion regulates attention: The relation between facial configurations, facial emotion, and visual attention. Vis. Cogn. 12, 51–84 (2005). Fox, E., Russo, R., Bowles, R. & Dutton, K. Do threatening stimuli draw or hold visual attention in subclinical anxiety?. J. Exp. Psychol. Gen. 130, 681–700 (2001). Gerdes, A. B., Alpers, G. W. & Pauli, P. When spiders appear suddenly: Spider-phobic patients are distracted by task-irrelevant spiders. Behav. Res. Ther. 46, 174–187 (2008). Soares, S. C., Esteves, F. & Flykt, A. Fear, but not fear-relevance, modulates reaction times in visual search with animal distractors. J. Anx. Disord. 23, 136–144 (2009). Clauss, K., Gorday, J. Y. & Bardeen, J. R. Eye tracking evidence of threat-related attentional bias in anxiety-and fear-related disorders: A systematic review and meta-analysis. Clin. Psychol. Rev. 93, 102142; 10.1016/j.cpr.2022.102142 (2022). Flykt, A., Lindeberg, S. & Derakshan, N. Fear makes you stronger: Responding to feared animal targets in visual search. Atten. Percept. Psycho. 74, 1437–1445 (2012). Miltner, W. H. R., Krieschel, S., Hecht, H., Trippe, R. & Weiss, T. Eye movements and behavioral responses to threatenting and nonthreatening stimuli during visual search in phobic and nonphobic subjects. Emotion 4, 323–339 (2004). Devue, C., Belopolsky, A. V. & Theeuwes, J. The role of fear and expectancies in capture of covert attention by spiders. Emotion 11, 768–775 (2011). Bjärtå, A., Flykt, A., & Sundin, Ö. The effect of using different distractor sets in visual search with spiders and snakes on spider-sensitive and nonfearful participants. Swiss J. Psychol. 72, 171–179 (2013). Boyd, R. Mistakes allow evolutionary stability in the repeated prisoner's dilemma game. J. Theor. Biol. 136, 47–56 (1989). Henderson, R. R., Bradley, M. M. & Lang, P. J. Emotional imagery and pupil diameter. Psychophysiology 55, e13050; 10.1111/psyp.13050 (2018). Santos, S. M., Fernandes, N. L. & Pandeirada, J. N. Same but different: The influence of context framing on subjective disgust, eye movements and pupillary responses. Conscious. Cogn. 108, 103462; 10.1016/j.concog.2022.103462 (2023). de Jong, P. J., van Overveld, M. & Peters, M. L. (2011). Sympathetic and parasympathetic responses to a core disgust video clip as a function of disgust propensity and disgust sensitivity. Biol. Psychol. 88, 174–179 (2011). Levenson, R. W. Autonomic nervous system differences among emotions. Psychol. Sci. 3, 23–27 (1992). Bayer, M., Sommer, W. & Schacht, A. Emotional words impact the mind but not the body: evidence from pupillary responses. Psychophysiology 48, 1554–1562 (2011). Rádlová et al . Emotional reaction to fear-and disgust-evoking snakes: Sensitivity and propensity in snake-fearful respondents. Front. Psychol. 11, 31; 10.3389/fpsyg.2020.00031 (2020). Arrindell, W. A., Mulkens, S., Kok, J. & Vollenbroek, J. Disgust sensitivity and the sex difference in fears to common indigenous animals.Behav. Res. Ther. 37, 273–280 (1999). Klorman, R., Weerts, T. C., Hastings, J. E., Melamed, B. G. & Lang, P. J. Psychometric description of some specific-fear questionnaires. Behav. Ther. 5, 401–409 (1974). Polák, J., Landová, E. & Frynta, D. Undisguised disgust: a psychometric evaluation of a disgust propensity measure. Curr. Psychol. 38, 608–617 (2019). Posit team RStudio. Integrated development environment for R. Posit Software, PBC, Boston, MA. http://www.posit.co/ (2022). Additional Declarations No competing interests reported. Supplementary Files supplementaryinformation.xlsx Cite Share Download PDF Status: Published Journal Publication published 28 Nov, 2023 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Major revision 16 Aug, 2023 Reviews received at journal 15 Aug, 2023 Reviewers agreed at journal 15 Aug, 2023 Reviews received at journal 29 Jul, 2023 Reviewers agreed at journal 28 Jul, 2023 Reviewers invited by journal 03 May, 2023 Editor assigned by journal 25 Apr, 2023 Editor invited by journal 01 Apr, 2023 Submission checks completed at journal 01 Apr, 2023 First submitted to journal 25 Mar, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2734657","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":188288447,"identity":"4e7d1473-f890-4ee2-90fb-6d918b914707","order_by":0,"name":"Eva Landová","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYHACxgMMDMxAmvkA8XqgWtgSSNbCY0Cccn6J5AcHfu6wljM4fubzhw9/7sjrNjA//oBPi+SMNIODvWfSjQ3O5G6TnMHzzHDbATYDvPYZnDlgcIC37XDizIbcbcw8EocZtx3gYUjAp8X+zPEPB/+CtPS/efz5j8Fhe5CWA3htYe8xOAyypV8ih0GaIeFwIlALYwM+LRLHewoOy7alG/NLPDOT7DlwOHnbYTZjfDoY+JvZNz5822Ytx8af/PjDjz+Hbbcdb8YfYlgAM4nqR8EoGAWjYBRgAgD0clE3QAkjNQAAAABJRU5ErkJggg==","orcid":"","institution":"Charles University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Eva","middleName":"","lastName":"Landová","suffix":""},{"id":188288448,"identity":"fac3c9e6-176c-4dbe-8f21-432a77d31722","order_by":1,"name":"Iveta Štolhoferová","email":"","orcid":"","institution":"National Institute of Mental Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Iveta","middleName":"","lastName":"Štolhoferová","suffix":""},{"id":188288449,"identity":"c26398d0-76bb-46bb-ab52-df822e3356a0","order_by":2,"name":"Barbora Vobrubová","email":"","orcid":"","institution":"Charles University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Barbora","middleName":"","lastName":"Vobrubová","suffix":""},{"id":188288450,"identity":"b30f91c6-18e2-40cf-949c-ba921ab49bc4","order_by":3,"name":"Jakub Polák","email":"","orcid":"","institution":"Charles University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jakub","middleName":"","lastName":"Polák","suffix":""},{"id":188288451,"identity":"cbc27013-a7d4-4cd1-97a2-80c1026eb23f","order_by":4,"name":"Kristýna Sedláčková","email":"","orcid":"","institution":"National Institute of Mental Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kristýna","middleName":"","lastName":"Sedláčková","suffix":""},{"id":188288452,"identity":"c6f5a559-f6ff-4353-90bf-43db3ffdc43c","order_by":5,"name":"Markéta Janovcová","email":"","orcid":"","institution":"Charles University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Markéta","middleName":"","lastName":"Janovcová","suffix":""},{"id":188288453,"identity":"05ba5c77-bcc2-4283-8084-3721f6d41601","order_by":6,"name":"Silvie Rádlová","email":"","orcid":"","institution":"National Institute of Mental Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Silvie","middleName":"","lastName":"Rádlová","suffix":""},{"id":188288454,"identity":"35c9519a-9b61-41eb-8338-ea28df37ba9c","order_by":7,"name":"Daniel Frynta","email":"","orcid":"","institution":"Charles University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"","lastName":"Frynta","suffix":""}],"badges":[],"createdAt":"2023-03-25 07:29:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2734657/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2734657/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-023-48229-8","type":"published","date":"2023-11-28T15:01:09+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":35289205,"identity":"86cbcb1e-a585-45d4-accd-258d1f185e15","added_by":"auto","created_at":"2023-04-04 19:50:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":184715,"visible":true,"origin":"","legend":"\u003cp\u003eResults of the model for reaction time – behavioral response. The grey bars at the bottom represent the number of participants with respective SPQ scores. Note that the slopes of only solid lines are significantly different from zero, hence the effect of the SPQ score is significant only for spider and crab distractors.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-2734657/v1/7abab8d5795f79cc21965f52.png"},{"id":35288136,"identity":"db702b37-f573-4411-90df-4c1006f4971c","added_by":"auto","created_at":"2023-04-04 19:42:11","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":134080,"visible":true,"origin":"","legend":"\u003cp\u003eResults of the image rating. Boxplots of fear (a) and disgust (b) ratings, and the effect of SPQ score (c) and DS-R score (d) on factors scores (rating of images); grey bars at the bottom represent the number of participants with respective scores.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-2734657/v1/cc3599df2b4419c2c6a6fa18.png"},{"id":35288137,"identity":"86d54754-7ce4-4d6b-a43e-558d48dee027","added_by":"auto","created_at":"2023-04-04 19:42:11","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":614634,"visible":true,"origin":"","legend":"\u003cp\u003eAn example of the experimental slide as shown to the participants (a) and as overlayed by areas of interest (b), and additional examples of animal distractors – one for each animal group (c). In the experimental slide example, the distractor is a snake, the false targets are on positions 1-18, and 20, and the true target is on position 19 (area of interest ‘Dot 19’). Target positions of the same type (level) are shown in the same color. The closest to the slide center are those in green (approx. 435 px), followed by the blue (approx. 498 px), yellow (approx. 627 px), purple (approx. 811 px), and red (approx. 897 px) ones (the distance was measured from the center of the dot to the center of the slide). Images in (c) are not in scale. Due to copyright restrictions, animal photos presented to the participants have been replaced by illustrations highly authentic to the original photo.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-2734657/v1/a062a67f1e2da75919003dea.png"},{"id":47561636,"identity":"8e1522cb-d25b-4a22-944a-4c3d48ba75f9","added_by":"auto","created_at":"2023-12-04 15:12:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1167914,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2734657/v1/d0030b8c-1ae0-4f80-8a5c-b220a9c7971a.pdf"},{"id":35288139,"identity":"08b20808-20f5-4b43-9b74-ec8fb89c265c","added_by":"auto","created_at":"2023-04-04 19:42:12","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":585644,"visible":true,"origin":"","legend":"","description":"","filename":"supplementaryinformation.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-2734657/v1/8f6cb2543f67f6ef3aac026a.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Attentional, emotional, and behavioral response toward spiders, scorpions, crabs, and snakes: Do they all scare us?","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOver the course of our evolutionary past, humans have developed several complex adaptations about how to respond to life-threatening stimuli such as various predators [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], venomous snakes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], or enraged conspecifics [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Early detection of these ancestral dangers is often accompanied by a strong emotional response, which further affects the following conscious attention and rapid adaptive behavioral response [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Evolutionary relevant threatening animal stimuli are thought to activate the fear module [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], a complex biopsychological system whose concept has been derived from the preparedness theory proposed by Seligman [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] and elaborated by Mineka and \u0026Ouml;hman [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Preparedness theory suggests that quick fear learning and its slow extinction are predominantly associated with those stimuli that posed threat to human ancestors. Numerous studies built upon the preparedness theory and fear module, testing their assumptions [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In this study, we focus on how fear-relevant animals affect attention during an animal-unrelated task.\u003c/p\u003e \u003cp\u003eBy far, the most often investigated animal in fear module research is the snake. In her Snake detection theory, Isbell [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] suggested that the evolution of the primate visual system has been strongly shaped by the need for rapid detection of snakes. A large body of evidence has been found in support of this hypothesis [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], although some discussion is being held on its ecological validity [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Several papers showed specific early as well as late attentional changes in brain activity in response to snakes [\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Snakes were also shown to be detected faster than other animals in visual search tasks using an eye-tracking camera [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], even in suboptimal visual conditions [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Venomous snakes also evoked elevated psychophysiological responses [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Recently, coevolution between snakes and primates was illustrated in an example of snake venom and resistance to it in primates [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Altogether, common fear and negative attitude toward snakes seem evolutionary well based [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eContrary to that, the origin of fear of spiders remains uncertain despite its relatively large prevalence in the general population. High and exaggerated fear of spiders, arachnophobia, is one of the most common anxiety disorders with a prevalence of 2.7\u0026ndash;6.1% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] or even 10% [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The majority of spider species have not been seriously dangerous for contemporary humans or their ancestors [29, reviewed in 30]. and thus, the evolutionary explanation of arachnophobia is questionable. Some authors suggest that fear of spiders is driven by contamination-based disgust (reviewed in [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]). Matchett and Davey [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] proposed the disease-avoidance model hypothesizing that spider phobia develops based on the disgusting properties of the spider [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] and fear of involuntary physical contact with spiders. Davey [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] suggested that these disgust-relevant properties of the spider had become apparent during the plague pandemics in the Middle Ages. As the etiology of the disease remained unknown, spiders served as a displaced target.\u003c/p\u003e \u003cp\u003eIn some studies, spiders are viewed as prototypical fear stimuli similar to snakes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], but event-related potential studies comparing attention to spiders, snakes, and other animals showed that the brain potential related to exogenous attention (P1) had the highest amplitude in response to snakes but not spiders, while enhanced attention-related brain activity (LPP) was found in response to both snakes and spiders [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Similarly, in a visual search task, adult participants detected snakes more quickly or accurately than spiders [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. In conclusion, the human reaction to snakes and spiders does not seem directly comparable.\u003c/p\u003e \u003cp\u003eAnother hypothesis suggests that fear and disgust of spiders is a generalization of fear and disgust of other disease-carrying invertebrates [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. On the one hand, He et al. [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] in their ERP study showed that there was no difference in attentional brain activation among spiders, wasps, bumblebees, or beetle stimuli, which pointed out to a high level of attentional generalization among stimuli. On the other hand, spiders and morphologically similar chelicerates are perceived highly specifically and differently compared to other invertebrates, including insects [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Generally, spiders are perceived very specifically in subjective emotional evaluations and people do not generalize them to other arthropods, whereas in experimental measures of attentional response, the degree of generalization varies and requires further investigation. A similar hypothesis suggesting that fear of spiders is a generalized fear of scorpions is also not supported by subjectively perceived fear or disgust. Scorpions from this perspective form a separate, albeit sister category to spiders [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Rudolfov\u0026aacute; et al. [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] investigated spontaneous attentional bias toward scorpions and spiders in a cross-cultural eye-tracking experiment. Higher attentional bias for scorpions as opposed to spiders was demonstrated in Somalis and a similar albeit smaller bias in Czechs.\u003c/p\u003e \u003cp\u003eIn the following eye-tracking study, we measured attentional, behavioral, and emotional reactions to spiders, crabs, and scorpions to uncover a pattern of generalization among these stimuli. For the investigation of early and late attentional response, an eye-tracking method is often combined with measuring reaction time by pressing a key or touching a screen. Several designs are usually employed: a visual search [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], an inattentional blindness paradigm task [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], or a flicker paradigm task [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. In this study, the investigated animal was used as a task-irrelevant distractor. A similar design was previously used, for example, by Zsid\u0026oacute; et al. [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. The participants were instructed to find numbers on a screen where a snake was also displayed, and the task-solving time was measured. We wanted to know if the distraction of attention by task-irrelevant animals was specific to the spider stimuli compared to other invertebrates (scorpions and crabs) in spider-fearful versus non-fearful participants. The results were further compared with those triggered by the snake, the prototypical evolutionary relevant threatening stimulus.\u003c/p\u003e \u003cp\u003eSpecifically, we focused on three types of responses that should be influenced by sensitivity to fear of spiders: (1) The attentional response \u0026ndash; participants with high fear of spiders will be distracted specifically by the spider images leading to higher latency in fixating the true target in both the within-subject (compared to other animal stimuli) and between-subject comparison (compared to participants with low fear of spiders). (2) The behavioral response \u0026ndash; the same effect would be manifested by a longer reaction time (pressing the response button). (3) The emotional response \u0026ndash; the higher the fear of the distractor animal, the wider the mean and maximal pupil size of the participant while watching the presentation slide. We predict the same direction although of a smaller magnitude for the disgust emotional response.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eAttentional response\u003c/h2\u003e \u003cp\u003e The attentional response differed between the participants and between the target positions within the participant (both incorporated as random factors), however, it was not significantly affected by any of the investigated explanatory variables. Hence, in the model for latency in fixating the true target for the first time, all fixed effects were successively reduced: Gender \u0026ndash; Age interaction (F\u0026thinsp;=\u0026thinsp;0.05, p\u0026thinsp;=\u0026thinsp;0.832), Animal category \u0026ndash; SPQ score interaction (F\u0026thinsp;=\u0026thinsp;2.16, p\u0026thinsp;=\u0026thinsp;0.091), Animal category (F\u0026thinsp;=\u0026thinsp;0.55, p\u0026thinsp;=\u0026thinsp;0.650), Gender (F\u0026thinsp;=\u0026thinsp;1.53, p\u0026thinsp;=\u0026thinsp;0.219), SPQ score (F\u0026thinsp;=\u0026thinsp;3.56, p\u0026thinsp;=\u0026thinsp;0.062), and Age (F\u0026thinsp;=\u0026thinsp;6.72, p\u0026thinsp;=\u0026thinsp;0.011).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eBehavioral response\u003c/h2\u003e \u003cp\u003eAs hypothesized, the latency of finding the true target was greater for participants with higher SPQ scores in images with the spider and crab distractors but not with scorpion or snake distractors. Neither the participant\u0026rsquo;s gender, age, nor their interaction affected the reaction time hence these effects were successively reduced: Gender \u0026ndash; Age interaction (F\u0026thinsp;=\u0026thinsp;0.10, p\u0026thinsp;=\u0026thinsp;0.754), Gender (F\u0026thinsp;=\u0026thinsp;1.18, p\u0026thinsp;=\u0026thinsp;0.281), and Age (F\u0026thinsp;=\u0026thinsp;3.34, p\u0026thinsp;=\u0026thinsp;0.070). In contrast, the animal category, SPQ score, and their interaction were kept in the final model: Animal (F\u0026thinsp;=\u0026thinsp;3.66, p\u0026thinsp;=\u0026thinsp;0.012), SPQ score (F\u0026thinsp;=\u0026thinsp;5.57, p\u0026thinsp;=\u0026thinsp;0.020), and Animal \u0026ndash; SPQ score interaction (F\u0026thinsp;=\u0026thinsp;4.95, p\u0026thinsp;=\u0026thinsp;0.002). The animal categories intercepts (estimated means for SPQ score\u0026thinsp;=\u0026thinsp;0) are 6.86 for the crab, 6.95 for the scorpion, 6.96 for the snake, and 6.89 for the spider. The intercept for the crab is significantly lower than the one for the snake and scorpion (p-values\u0026thinsp;\u0026lt;\u0026thinsp;0.004). As predicted, the reaction time for the spider is higher with a higher SPQ score (p\u0026thinsp;=\u0026thinsp;0.002). This holds also for the crab (p\u0026thinsp;=\u0026thinsp;0.007), but not the scorpion (p\u0026thinsp;=\u0026thinsp;0.135) or snake (p\u0026thinsp;=\u0026thinsp;0.158). The slope coefficient for the spider is therefore significantly different from the one for the scorpion (p\u0026thinsp;=\u0026thinsp;0.005) and snake (p\u0026thinsp;=\u0026thinsp;0.003) but not for the crab (p\u0026thinsp;=\u0026thinsp;0.453). Note that all reported estimates were computed from natural logarithm-transformed values. The results are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBehavioral response \u0026ndash; results of the model for reaction time. For participants with low fear of spiders, reaction time was the largest for snake and scorpion distractors. Sensitivity to fear of spiders affected only reaction time for spider and crab distractors. Hence we found the greatest difference in reaction times between spider-scorpion and spider-snake in participants with various levels of spider fear. Est \u0026ndash; an estimate of the intercept/coefficient/contrast, 95% CI \u0026ndash; 95% confidence interval, t \u0026ndash; t-value, p \u0026ndash; p-value, p-values\u0026thinsp;\u0026lt;\u0026thinsp;0.0083 are in bold. Note that all estimates were computed from natural logarithm-transformed values.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003eIntercept\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003eSPQ score coefficient\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLevel / Contrast\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEst (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eEst (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.86 (6.75; 6.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.01 (0.003; 0.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScorpion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.95 (6.84; 7.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.006 \u003c/p\u003e \u003cp\u003e(-0.002; 0.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.135\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSnake\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.96 (6.85; 7.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.005 \u003c/p\u003e \u003cp\u003e(-0.002; 0.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.158\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpider\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.89 (6.78; 7.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.01 (0.004; 0.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrab \u0026ndash; Scorpion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-2.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.029\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrab \u0026ndash; Snake\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-3.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.019\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrab \u0026ndash; Spider\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.351\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e-0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-0.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.424\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScorpion \u0026ndash; Snake\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.846\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.0003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.879\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScorpion \u0026ndash; Spider\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.051\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e-0.006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-2.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.003\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSnake \u0026ndash; Spider\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e-0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-3.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eEmotional response\u003c/h2\u003e \u003cp\u003eRegarding the pupil metrics, we found that participants\u0026rsquo; maximal pupil size was larger when the animal distractor was rated as more fear-eliciting. Contrary to that, no effect of fear on mean pupil size nor of disgust on either response was found. Results of the models for trial maximal pupil size: Fear \u0026ndash; F\u0026thinsp;=\u0026thinsp;10.16, p\u0026thinsp;=\u0026thinsp;0.001, intercept\u0026thinsp;=\u0026thinsp;993.25, Fear coefficient\u0026thinsp;=\u0026thinsp;3.054; Disgust \u0026ndash; F\u0026thinsp;=\u0026thinsp;6.15, p\u0026thinsp;=\u0026thinsp;0.013. Results of the models for trial mean pupil size: Fear \u0026ndash; F\u0026thinsp;=\u0026thinsp;6.10, p\u0026thinsp;=\u0026thinsp;0.014; Disgust \u0026ndash; F\u0026thinsp;=\u0026thinsp;3.71, p\u0026thinsp;=\u0026thinsp;0.054.\u003c/p\u003e \u003cp\u003eResults of image ratings according to elicited fear and disgust are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, respectively. Results of FAs for fear and disgust both revealed a simple structure of four factors with Factor 1 loaded by spider ratings, Factor 2 by snake, Factor 3 by crab, and Factor 4 by scorpion ratings. The rating of the antelope did not correlate with any of the factors. Detailed results of FAs are shown in Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e. In successive modeling, the effect of some of the tested variables (SPQ score, DS-R score, Gender, Age, and Gender \u0026ndash; Age interaction) proved significant only in a few cases. Spiders were rated as more fear-eliciting by participants with a higher SPQ score (Factor 1 of Fear FA: SPQ score \u0026ndash; F\u0026thinsp;=\u0026thinsp;86.56, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; intercept=-1.150, SPQ score coefficient\u0026thinsp;=\u0026thinsp;0.092). Similarly, they were rated as more disgust-eliciting by those with a higher SPQ and DS-R score (Factor 1 of Disgust FA: SPQ score \u0026ndash; F\u0026thinsp;=\u0026thinsp;104.95, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; DS-R score \u0026ndash; F\u0026thinsp;=\u0026thinsp;27.15, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; intercept=-1.702, SPQ score coefficient\u0026thinsp;=\u0026thinsp;0.092, DS-R score coefficient\u0026thinsp;=\u0026thinsp;0.012).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOn the other hand, snakes were rated as more fear-eliciting by participants with a lower SPQ and higher DS-R score (Factor 2 of Fear FA: SPQ score \u0026ndash; F\u0026thinsp;=\u0026thinsp;9.42, p\u0026thinsp;=\u0026thinsp;0.003; DS-R score \u0026ndash; F\u0026thinsp;=\u0026thinsp;13.48, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; intercept=-0.451, SPQ score coefficient=-0.048, DS-R score coefficient\u0026thinsp;=\u0026thinsp;0.022) and as more disgust-eliciting by people with a higher DS-R score (Factor 2 of Disgust FA: DS-R score \u0026ndash; F\u0026thinsp;=\u0026thinsp;15.55, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; intercept=-1.140, DS-R score coefficient\u0026thinsp;=\u0026thinsp;0.024). The rating of spiders or snakes was not affected by the participant\u0026rsquo;s gender, age, or their interaction. Neither the fear nor disgust rating of crabs was affected by any of the investigated variables. The disgust rating of scorpions seemed to be affected by the participant\u0026rsquo;s gender-age interaction but the effect disappeared when an insignificant term (DS-R score) was reduced from the model. The effect of SPQ and DS-R scores on factor scores (rating of images) is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, respectively. Detailed results of modeling are shown in Supplementary Table S2.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe found no difference in the attentional but a large difference in the behavioral response of spider-fearful participants to images with spider distractors. As predicted, spider-fearful participants reacted slower when there was a spider distractor compared to snake and scorpion distractors. Their response was also slower compared to the control group of non-fearful participants. Concerning our original predictions, the results of the pupillometric models were inconclusive. Ratings of images confirmed that the SPQ score well described participants\u0026rsquo; subjective perception of spiders.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eAttentional response\u003c/h2\u003e \u003cp\u003eWe hypothesized that participants with high fear of spiders would show higher latency in fixating the true target both compared to other animal stimuli and to participants with low fear of spiders. However, we found no such difference as neither the SPQ score nor the animal image proved to have a significant effect on the latency of the true target's first fixation. Fear-eliciting or threatening stimuli have long been hypothesized to capture human attention. This was illustrated, for example, by Lundqvist \u0026amp; \u0026Ouml;hman [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] or Yorzinski et al. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Originally, two mechanisms behind this phenomenon were suggested. It could be that fear-eliciting stimuli attract the participant\u0026rsquo;s attention more easily, or that fear-eliciting stimuli hold the participant\u0026rsquo;s attention longer (see for example [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]). In recent years, a consensus seemed more inclined towards the latter mechanism [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e], however, a last-year meta-analysis suggests that both mechanisms can be relevant [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Our results seem to support this hypothesis as well, although we could not test it directly, because the central placement of animal distractors led to zero latency of the first gaze on the animal in all cases. However, in the analysis of true target latencies, we found no effect of animal and SPQ score for the first gaze but a clear effect for the conscious reaction. This is in support of the hypothesis of fear-eliciting stimuli holding attention.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBehavioral response\u003c/h2\u003e \u003cp\u003eAs we predicted, the spider-fearful participants\u0026rsquo; behavioral response was slower in comparison to non-fearful participants, most probably because they were distracted by the spider images. Importantly, spider-fearful participants were specifically distracted by spider stimuli and not by scorpions or snakes (non-significant SPQ score coefficients, see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). It has been previously shown that emotions can modulate attention toward a stimulus and facilitate its detection. In a visual search task, Soares et al. [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] reported that participants found the animal they were afraid of faster than a non-feared but fear-relevant animal. Specifically, spider-fearful participants found spiders faster than snakes and conversely, snake-fearful participants found snakes faster than spiders. Flykt et al. [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e] additionally found that fearful participants pressed the response button harder when the target animal was their specifically feared animal. Even when the feared animal is not the target, it can affect attention. Miltner et al. [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e] found that the presence of task-irrelevant spider distracters slowed the detection of mushroom targets in spider-fearful participants. Our results, therefore, are in agreement with these studies.\u003c/p\u003e \u003cp\u003eIn this study, we placed the distractor stimuli in the center of the slide and started a new trial only when the participant\u0026rsquo;s gaze was fixed on the center. Consequently, the participants were aware that one of four animals would soon appear in the center of their visual field. While non-fearful participants did not differentiate between the animals in a way that would affect their \u0026ldquo;success\u0026rdquo; in solving the task, spider-fearful participants were selectively affected by spider and crab distractors. This suggests that spider-fearful participants were alert and anticipated the appearance of frightening stimuli. The importance of expectations was previously investigated by Devue et al. [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e] who showed that spider-fearful participants performed poorly in trials with potential spider stimuli but similarly well as the control group when they knew no spider could be expected. Higher alertness when potentially dangerous stimuli are suspected to appear is crucial for the quick activation of an appropriate physiological and behavioral response. Even though high fear of spiders and/or arachnophobia might not be adaptive themselves and are also often consciously considered \u0026ldquo;nonsensical\u0026rdquo;, they activate highly adaptive pathways.\u003c/p\u003e \u003cp\u003eSurprisingly, although crabs were not subjectively rated as fear- or disgust-eliciting by the spider-fearful participants, they distracted them similarly to spiders. We account for this to the high morphological similarity between crabs and spiders (specifically those selected here as stimuli) which made them easy to be confused by just a glance. From an adaptive point of view, the threshold for what is and what is not a feared stimulus has to change to secure as few false-negative responses (overlooked real signals) as possible when the participant\u0026rsquo;s attention is directed toward the animal-unrelated task. This, however, can be only done at the expense of false positives (responses to incorrect stimuli). Still, human attention is very fine-tuned for the spider stimuli because scorpions \u0026ndash; similar in appearance and biologically close relatives to spiders \u0026ndash; did not affect the success of solving the task. A similar result was also shown by New \u0026amp; German [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] where participants\u0026rsquo; responses to spiders and house flies differed in an inattentional blindness task.\u003c/p\u003e \u003cp\u003eInterestingly, the scorpion distractors\u0026rsquo; effect on the behavioral response did not resemble the effect of spider but rather snake distractors in our dataset. This was quite surprising because snakes have long been considered a special fear stimulus. This notion was supported by several studies (see Introduction) including the eye-tracking ones that showed faster or more accurate detection of snakes (e.g., see [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]). Later, this view was questioned. It was pointed out that snake detection could have been facilitated simply because they were compared to flowers and mushrooms and not to other animals [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. Later again though, the snake\u0026rsquo;s specificity was confirmed with regards to its distractor properties or when detection took place under challenging setups [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo the best of our knowledge, the current study is the first one that utilized scorpions as distractor stimuli and compared them to snakes. For participants with low fear of spiders (i.e., the general population), both snakes and scorpions triggered a behavioral response more than the control, fear-irrelevant stimulus \u0026ndash; the crab. This supports the hypothesis of the scorpion as the evolutionary fear-relevant stimulus similar to the snake (see [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] for details). However, the distractor effect of crabs increased with the participant\u0026rsquo;s SPQ score inevitably influencing the estimated crab-snake and crab-scorpion differences. Although we find the similarity between snakes and scorpions highly interesting, more research is certainly needed. Nonetheless, it seems that two types of generalization might occur: (1) Either the generalization is based on function, and in this case, associated emotions seem adaptive (i.e., both snakes and scorpions are objectively fear-relevant, therefore a fear-mediated behavioral response is generally advantageous). (2) Alternatively, the generalization is based on physical features (as we suspect was the case for spiders and crabs) which may be advantageous, disadvantageous, or neither of those depending on the situation. It is worth pointing out, though, that from the evolutionary perspective, it is also adaptive to allow some level of mistakes [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eEmotional response\u003c/h2\u003e \u003cp\u003eLastly, we predicted that the participants\u0026rsquo; mean and maximal pupil size would be wider when watching the presentation slide with subjectively more feared animal distractors. We found this effect for the maximal but not the mean pupil size. Further, we did not find any effect of perceived disgust on maximal or mean pupil size. It is generally agreed upon that emotional stimuli affect pupil diameter. Both positive and negative emotional stimuli are usually associated with pupil dilation [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e], however, pupil constriction was also noted in some cases. Specifically, pupil constriction was usually found in studies focusing on disgust [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e], which involves the activation of the parasympathetic nervous system [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. On the contrary, fear elicits a sympathetic activation, leading to pupil dilation [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. In this regard, the spider is a particular stimulus because it evokes both strong fear and disgust, even though fear is usually stronger [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]; see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea,b). Additionally, it was also shown that pupil dilation increased with a cognitive effort to solve the task. Emotions and cognition can also interact [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e]. In other words, pupil dilation might be the result of several processes and the extent to which each may affect the pupil diameter remains unclear. In this study, we mainly focused on the attentional and behavioral response and pupillometry was rather supplemental, hence the feasibility of some analyses was limited. Additional cautiousness should be executed when interpreting the results because while EyeLink1000 offers pupillometric characteristics, its primary purpose is different.\u003c/p\u003e \u003cp\u003eBased on the analysis of image ratings, all images of one type of animal were perceived similarly to each other but as distinct from images of different types of animals. This confirmed that the images were appropriately selected to represent one category and that their grouping into one factor of four levels in statistical modeling was justified. Unsurprisingly but importantly, we also confirmed that participants with a higher SPQ score rated spiders as more fear-eliciting and disgust-eliciting than participants with a lower SPQ score (see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This means that a subjective animal rating, a semi-objective SPQ score, and an objective behavioral response are in good concordance and give similar results. In research on the effect of fear elicited by spiders, participants are often divided into two groups which represent two extremes, meaning participants with medium fear or ambiguous emotions (the middle of the scale) are not represented [e.g., 49]. This approach has several advantages, e.g., thanks to the higher difference between the participants, smaller effects can be detected. However, we find relatively even coverage along the whole SPQ scale useful (see, Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec), as well, since it allows us to access the value of behavioral response for any SPQ score (within the included range).\u003c/p\u003e \u003cp\u003eWe further found that fear of snakes declined with higher SPQ scores (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec). This means that, in our sample, participants who were not afraid of spiders tended to fear snakes more than spider-fearful participants. However, we do not think that this result should be generalized to the population level as it is most probably a by-product of the experimental design (see also [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]). On the one hand, a high fear rating of snake stimuli should be expected since they were all highly venomous vipers [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. On the other hand, to spider-fearful participants, spiders are the most salient stimuli no matter the objective dangerousness of others and therefore snakes are rated as less frightening in comparison. Combined, this led to spider-fearful participants being seemingly less likely to fear snakes than the control group. Our explanation is also supported by the frequency of self-reported fear of snakes (yes or no answer to the question: \u0026ldquo;Are you afraid of snakes more than you consider usual?\u0026rdquo;). Ten (out of 55) participants from the control group and 13 (out of 50) spider-fearful participants reported being (also) afraid of snakes \u0026ndash; a rather similar proportion.\u003c/p\u003e \u003cp\u003eFinally, we found that fear of snakes and disgust of spiders and snakes increased with an increasing DS-R score, but the relationship was rather weak (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed). This is in concordance with Arrindell et al. [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e] who also found that disgust sensitivity held only little predictive value about animal fears.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this study, we replicated the general experimental design of several previous studies (i.e., the task-irrelevant distractor design; [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]) and found comparable results. However, we also modified the design in numerous important and new ways. First, we recruited participants covering quite evenly almost the full range of the SPQ scale. Second, we used rather large animal images (the distractors) and placed them in the center of the visual field to ensure that participants would gaze at them and enhance the potential distractor effect. Third, we added two new uninvestigated animal stimuli \u0026ndash; a crab and a scorpion. Interestingly, the effect of these two distractors proved to be very different from each other \u0026ndash; while the effect of the crab quite closely resembled the effect of the spider distractor, the scorpion was more similar to the snake distractor. We hypothesize that spider-fearful participants might have mistaken the crab for a spider because of their high morphological similarity in this stimulus set. In other words, spider-fearful participants generalized their reactions from spiders to crabs based on their shared physical characteristics. Contrary, participants with no fear of spiders were distracted the most by snakes and scorpions. No difference between snake and scorpion distractors was found supporting the notion that scorpions are also prioritized, evolutionary relevant stimuli. To conclude, subjectively feared spiders distracted participants from solving the task to a greater extent than objectively more fear-relevant snakes and scorpions. This supports the view of emotions as an important mediator in behavioral and physiological responses.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003eA total number of 114 participants were originally recruited for the experiment. Of these, 50 participants were undergraduate Czech or Erasmus students that participated for course credit in Ethology and sociobiology course. The remaining 64 participants were recruited from our database of Czech research volunteers based on their scores on the Spider Questionnaire (SPQ, [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e]). Seven participants finished the eye-tracking experiment but chose not to follow through with the image rating (two participants) or completion of the questionnaires (five participants), hence their data were excluded from the analyses. Due to technical difficulties during the eye-tracking data extraction, the data of two additional participants had to be excluded. Therefore, the final sample consisted of 105 participants, 84 women, and 21 men (mean age 25.70 years, range 18\u0026ndash;49). Based on their SPQ scores, 55 participants (38 women) had none to moderate fear of spiders (SPQ\u0026thinsp;\u0026lt;\u0026thinsp;16), while the remaining 50 participants (46 women) had high or very high fear of spiders (SPQ\u0026thinsp;\u0026ge;\u0026thinsp;16; [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]). All the participants had a normal or corrected-to-normal vision.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStimuli\u003c/h2\u003e \u003cp\u003eEach eye-tracking stimulus slide (1920 x 1080 pixels) was a color image of an animal (the distractor) surrounded by 19 dots (false targets) and 1 square (true target) placed on a neutral 20% grey background (see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The animal images were sourced from the internet or our database. Criteria for the selection were good resolution of the image, full-body depiction of the animal, and \u0026ldquo;neutral\u0026rdquo; body posture. The animal\u0026rsquo;s original background was cut off and it was placed and sized to fit into the central area of approx. 640 x 540 px. Animal images were of four categories \u0026ndash; crabs, scorpions, snakes, and spiders \u0026ndash; each represented by five different species. Dots had a diameter of 29 px and the side length of the squares was 26 px making the shapes comparable in size (their area, as well as width and height); all dots and squares were black. They were placed in a 6 by 4 grid with four central positions left out for the animal image. Target positions were of five types (levels) based on their distance from the center. Positions 3, 4, 17, and 18 were closest to the center while positions 1, 6, 15, and 20 were the most distant (see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb). A total of 20 unique experimental slides were created using each combination of the animal category and true target position level just once. Additionally, images of antelopes in the same layout were used to create five practice stimuli.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFor the eye-tracking analysis, 21 unique areas of interest (AOI) were defined. In the center, there was the animal AOI (640 x 540 px in size). Surrounding each of the 20 grid positions, there were the dot 01\u0026ndash;20 AOIs (each 320 x 270 px in size). The AOIs did not overlap and covered the whole slide (see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eProcedure\u003c/h2\u003e \u003cp\u003eFirst, each participant was briefed about the subsequent tasks and gave written consent for his/her participation in the research. The eye-tracking experiment followed. Then, they were instructed to rate the presented stimuli based on the level of elicited fear and disgust. Lastly, they completed two questionnaires: the Spider Questionnaire (SPQ; Czech translation by Pol\u0026aacute;k et al. [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]) and the Disgust Scale-Revised (DS-R; Czech translation by Pol\u0026aacute;k et al. [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]). If the participants already completed these questionnaires as a part of previous research (as was the case for all non-student and some student participants), this last step was skipped. All instructions and questionnaires were given in Czech to Czech and Slovak participants and in English to Erasmus student participants (originally from 8 other European countries).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eEye-tracking\u003c/h2\u003e \u003cp\u003eEye movements were recorded using the EyeLink1000 eye-tracking device; for measuring the reaction times, participants answered using a response box. The participants were seated in front of a 19-inch screen (Full HD resolution, refresh rate 60 Hz) and their head was fixed using a chinrest at a distance of 70 cm from the screen. In the beginning, they answered four questions: age, gender, handedness, and country of origin. Next, the device was calibrated using a standard nine-point calibration procedure, involving the fixation of ten target crosses presented on the computer screen positioned on a three-by-three grid (the first and last target cross was presented in the center). The calibration was subsequently validated with the average allowed error\u0026thinsp;\u0026le;\u0026thinsp;0.5\u0026deg; and maximally allowed error\u0026thinsp;\u0026le;\u0026thinsp;1\u0026deg; of the visual angle. If the error was higher, the device was adjusted, and calibration and validation were repeated. After successful validation, the experimental task was explained in detail. Participants were instructed to find the square as fast as possible, signal the finding by pressing any button of the response box, and keep their gaze on the square until the whole stimulus slide disappeared. Slides with stimuli presented for 5 seconds (trial) alternated with slides presenting a target cross in the center; the next stimulus slide was presented only after the participant fixated on the target cross. Firstly, five practice stimuli were presented to the participants to get familiar with the response box and the task. Following the practice stimuli, they were offered an opportunity to ask questions. Next, all 20 stimuli were presented in two series, each time in a random order (different for each participant). In total, the experiment consisted of 5 practice trials and 40 experimental trials. The experimental setup was designed using the SR-Research Experiment Builder.\u003c/p\u003e \u003cp\u003eUsing the DataViewer (SR-Research), we extracted the following variables. For the whole trial: reaction time (RT), trial dwell time, trial fixation count, median fixation duration, blink count, minimal pupil size, maximal pupil size, mean pupil size, saccade count, the total number of visited areas of interest, and sequence of visited areas of interest. For each area of interest (AOI), we additionally extracted AOI dwell time, AOI fixation count, and AOI latency of the first, second, and third fixation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eRating of images\u003c/h2\u003e \u003cp\u003eParticipants rated 21 animal images in total \u0026ndash; 20 experimental images and one image of an antelope used in the practice trial. We uploaded the images to a special web application available at \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e\u003ca href=\"http://www.krasazvirat.cz\" target=\"_blank\"\u003ewww.krasazvirat.cz\u003c/a\u003e\u003c/span\u003e\u003cspan address=\"http://www.krasazvirat.cz\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Each image was rated on perceived fear and disgust on a seven-point Likert scale (1 corresponded to no fear/disgust, 7 corresponded to very strong fear/disgust). The animals were rated on both emotions at once, and the order of the images was random and different for each participant. Before the rating, each participant filled in a short questionnaire regarding their age, gender, type, and level of education, and whether they considered themselves to be afraid of any animal(s) more than they perceived as usual.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eFirstly, we analyzed data accessed from the eye-tracking experiment; only data from experimental trials were analyzed. We used linear mixed-effects models (LMM) as implemented in the software RStudio [\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e], package nlme. In all models, we used the participant\u0026rsquo;s ID and target position (5 levels, see Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb) within the participant\u0026rsquo;s ID as the random effect. To test our attention and behavioral response-related hypotheses, we successively built models with latency in fixating the true target for the first time and the reaction time as response variables, and the Animal category, SPQ score, and Animal category \u0026ndash; SPQ score interaction as fixed effects. We also checked for the effect of Gender, Age, and Gender \u0026ndash; Age interaction. As neither of the response variables had a normal distribution, we used a natural logarithm transformation. In the emotional response set of models, mean and maximal pupil size were response variables, while fear and disgust respectively were used as fixed effects and the participant\u0026rsquo;s ID was used as a random effect. Fixed effects that did not prove significant were successively reduced. To avoid false-positive effects as a result of testing six variables from one dataset, we set α\u0026thinsp;=\u0026thinsp;0.0083 (Bonferroni correction).\u003c/p\u003e \u003cp\u003eSecondly, we analyzed the rating of images. To avoid multiple testing, we performed factor analysis (FA) separately for fear and disgust rating. We employed the principal component method, extracted four factors, and used the Varimax normalized rotation. For each factor, we extracted factor scores and hence defined eight new variables (factors). We used linear models (LM) as implemented in RStudio, to test the effect of SPQ score and DS-R score, as well as Gender, Age, and Gender \u0026ndash; Age interaction on the factor scores (participants\u0026rsquo; rating of images, eight models in total). Variables and their interactions that did not prove significant were successively reduced. We again implemented a Bonferroni correction and set α\u0026thinsp;=\u0026thinsp;0.00625 to avoid reporting false-positive effects.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eEthical note\u003c/h2\u003e \u003cp\u003eAll experimental protocols were approved by the Ethics Commission of the National Institute of Mental Health (approval no. 117/18, granted on 28 March 2018). The authors also confirm that all experiments were performed in accordance with relevant guidelines and regulations (such as the Declaration of Helsinki). Written informed consent was obtained from all participants included in the study.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in the Supplementary Information files (Supplementary Table S3). For stimuli slides, please contact the corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank Ms. Lilit Farsiyan for her support with data collection and all our volunteers who kindly agreed to take part in this research.\u0026nbsp;This project has been supported by the Czech Scientific Foundation (GAČR), project No. 19-07164S, awarded to EL.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: DF, EL, SR; data curation: I\u0026Scaron;, BV; formal analysis: I\u0026Scaron;, DF; funding acquisition: EL; investigation: I\u0026Scaron;, BV, KS; methodology: SR VB, MJ; project administration: MJ; supervision: El, DF; writing \u0026ndash; original draft: I\u0026Scaron;, EL, JP. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests Statement:\u0026nbsp;\u003c/strong\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eYorzinski, J. L., Penkunas, M. J., Platt, M. L. \u0026amp; Coss, R. G. Dangerous animals capture and maintain attention in humans. Evol. Psychol. 12, 534\u0026ndash;548 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u0026Ouml;hman, A., Flykt, A. \u0026amp; Esteves, F. Emotion drives attention: detecting the snake in the grass. J. Exp. Psychol. Gen. 130, 466\u0026ndash;478 (2001).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFox, E., Russo, R. \u0026amp; Dutton, K. 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Posit Software, PBC, Boston, MA. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.posit.co/\u003c/span\u003e\u003cspan address=\"http://www.posit.co/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-2734657/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2734657/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSpiders evoke significant fear and disgust in many people; such a complex response has been formed throughout human evolution. However, most spiders do not present a serious threat, so the evolutionary explanation is controversial. We suggest that other chelicerates, e.g., scorpions, might have been important in the formation and fixation of the spider-like category. In this eye-tracking study, we checked for some aspects of the attentional, behavioral, and emotional response to the spider, scorpion, snake, and crab stimuli used as task-irrelevant distractors. Results showed that spider-fearful participants were selectively distracted by spiders, but also by crabs which were not consciously rated as fear-eliciting. We hypothesize that spider-fearful participants might have mistaken crabs for spiders based on their shared physical characteristics. Contrary, participants with no fear of spiders were distracted the most by snakes and scorpions. No difference between snake and scorpion distractors was found supporting the notion that scorpions are also prioritized, evolutionary relevant stimuli. We conclude that scorpions are evolutionary fear-relevant stimuli, however, the generalization between scorpions and spiders was not supported in spider-fearful participants. This result might be important for a better understanding of the evolution of spider phobia.\u003c/p\u003e","manuscriptTitle":"Attentional, emotional, and behavioral response toward spiders, scorpions, crabs, and snakes: Do they all scare us?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-04-04 19:42:07","doi":"10.21203/rs.3.rs-2734657/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2023-08-16T07:32:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-08-15T08:45:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"fc5ec98b-6d84-4a10-b42f-0145bea8bde3","date":"2023-08-15T07:17:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-07-29T06:39:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"f38bd275-e3fa-407d-bba3-5bf1eb2e326a","date":"2023-07-28T04:24:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-05-03T08:41:47+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-04-25T12:52:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2023-04-01T08:13:09+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-04-01T07:59:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2023-03-25T07:18:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"58d923c4-2d1e-477c-acc5-523471176b69","owner":[],"postedDate":"April 4th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":20376084,"name":"Biological sciences/Psychology"},{"id":20376085,"name":"Biological sciences/Psychology/Human behaviour"}],"tags":[],"updatedAt":"2023-12-04T15:11:47+00:00","versionOfRecord":{"articleIdentity":"rs-2734657","link":"https://doi.org/10.1038/s41598-023-48229-8","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2023-11-28 15:01:09","publishedOnDateReadable":"November 28th, 2023"},"versionCreatedAt":"2023-04-04 19:42:07","video":"","vorDoi":"10.1038/s41598-023-48229-8","vorDoiUrl":"https://doi.org/10.1038/s41598-023-48229-8","workflowStages":[]},"version":"v1","identity":"rs-2734657","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2734657","identity":"rs-2734657","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}