Processing of inner bodily signals: evidence and insight from adolescence

1 1 Processing of inner bodily signals: evidence and insight from adolescence 2 3 4 Silvia Canino 1*, Valentina Torchia2, Erica Dolce1, Irene Ruffo2, Teresa Iona1, 5 Simona Raimo1, Liana Palermo1* 6 7 1. Department of Medical and Surgical Sciences, Magna Graecia University of 8 Catanzaro, Catanzaro, Italy. 9 2. Department of Health Sciences, Magna Graecia University of Catanzaro, Catanzaro, 10 Italy. 11 12 13 14 * Corresponding author 15 E-mail: [email protected] (S.C.); [email protected] (L.P.) 16 17 18 19 20 21 22 23 24 25 .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 2 1 Abstract 2 Interoception, the sense of inner bodily signals, plays a key role in emotional 3 regulation, cognition and mental health. While its relevance in adulthood has been 4 extensively explored, less is known about how these abilities develop during 5 adolescence, a period characterised by significant physical and psychological changes. 6 This study aimed to investigate three distinct dimensions of interoception — accuracy, 7 sensitivity and awareness — in adolescents and adults to better understand the 8 developmental profile of this sense. 9 Fifty-four adolescents (aged 12–14) and 50 adults (aged 25–34) completed the 10 Heartbeat Monitoring Task to assess their actual ability to detect heartbeats, their 11 confidence in this ability, and the confidence-accuracy correspondence, and a 12 questionnaire on the tendency to focus on bodily sensations. The study also examined 13 where participants localised bodily sensations during the interoceptive task. 14 The results revealed no significant differences in interoceptive accuracy between the 15 two groups. Both age groups exhibited similar body localisation patterns, primarily 16 focusing on the chest during heartbeat detection. However, adolescents showed 17 significantly lower metacognitive awareness of their ability to perceive internal bodily 18 sensations, and higher focus on interoceptive sensations, as reflected in their higher 19 confidence ratings and questionnaire scores. No significant correlations emerged 20 among the three interoceptive dimensions in either group, which supports the view that 21 these dimensions represent independent components of interoception. These findings 22 suggest that, while basic interoceptive detection may be established by early 23 adolescence, the capacity to accurately reflect on these internal sensations continues 24 to mature into adulthood. The mismatch observed between adolescents' heightened .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 3 1 bodily focus and their limited metacognitive insight may partly help explain why 2 adolescence is a period of increased vulnerability to mental health difficulties. 3 4 Introduction 5 Interoception, the sense of the physiological condition of the inner body, is integral to 6 how we experience and interpret bodily signals [1,2]. This sense encompasses 7 sensations and representations of physiological signals, such as the heartbeat, itchiness 8 and air hunger [1]. Research has highlighted the importance of interoception in 9 emotional regulation, cognition and overall well-being [3-8]. 10 On a conscious level, interoception can be operationalized along three main 11 dimensions: (i) interoceptive accuracy (IAcc), which refers to performance on 12 objective tasks like heartbeat detection; (ii) interoceptive sensibility (ISe), which is the 13 self-evaluated tendency to focus on interoceptive signals, measured through 14 questionnaires; and (iii) interoceptive awareness (IAw), which is the metacognitive 15 ability to assess how accurately one perceives internal signals, evaluated through the 16 correspondence between confidence and actual performance [9]. This taxonomy is 17 further supported by evidence suggesting differential contributions of these 18 dimensions on cognition (e.g., [10, 3]) and their different relations with mental health 19 difficulties (e.g., [11, 12]). 20 Despite the growing recognition of interoception’s role in shaping psychological 21 functioning, as highlighted in a seminal review on interoceptive development by 22 Murphy et al. [13], our understanding of how interoception develops across the 23 lifespan remains limited. In particular, research explicitly investigating interoception 24 during typical adolescence is still scarce (for a similar argument, see also [14]). .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 4 1 Adolescence, however, is a period of life that can be particularly relevant for 2 interoceptive learning, as it is characterised by significant body changes [13, 15]. 3 Adolescence is also marked by significant maturation of neural circuits involved in 4 processing internal bodily signals, influencing how adolescents perceive and respond 5 to internal states such as hunger, fatigue, and emotional arousal [16]. The maturation 6 of interoceptive processes during this period seems to be linked to the development of 7 self-regulation and emotional resilience [17]. Also, disruptions in interoceptive 8 processing during adolescence can contribute to the onset of mental health disorders, 9 such as anxiety and depression [6]. 10 Recent neurophysiological studies have started to explore how interoception manifests 11 in the adolescent brain. For example, Mai et al. [18] showed that heartbeat-evoked 12 potentials (HEPs), a neural marker of interoceptive processing, are associated with an 13 IAcc measure but not with an ISe measure in adolescents, providing objective evidence 14 of the neurocognitive underpinnings of bodily awareness in this age group. 15 However, not only have very few studies directly investigated interoceptive 16 dimensions in samples of healthy adolescents and adults, but the existing evidence is 17 also mixed (for an overview, see [13, 14]). For example, May et al. [19] reported 18 different neural activity but no differences at the behavioural level between 16 19 adolescents (15-17 yrs), 19 young adults (20-28 yrs) and 19 mature adults (29-55 yrs) 20 in an interoceptive task probing soft touch. Yang et al. [20], instead, found higher 21 interoceptive accuracy in a sample of 50 adolescents (12-16 yrs) as compared to a 22 sample of 50 adults (23-54 yrs), a finding that is in contrast with the idea that there is 23 a disruption of interoception during adolescence [14]. However, considering that 24 physiological ageing is associated with a reduction in interoception [13,14, 21] and 25 that this last study included a sample of adults with a broad age range, it is difficult to .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 5 1 determine whether adolescents truly performed better on the task, or whether the effect 2 was due to the inclusion of middle-aged adults in the comparison group. In this study, 3 a subsample of participants (35 adolescents and 21 adults) was also given a measure 4 of ISe (i.e., Multidimensional Assessment of Interoceptive Awareness; [22]), and, in 5 this case, adolescents showed a lower tendency to actively listen to the body for 6 insight. 7 Qualitative findings also suggest that adolescents may experience body awareness in 8 highly individualised ways, shaped by both bodily changes and psychological 9 development. For instance, Pérez-Peña et al. [23] found that adolescents and young 10 adults described their interoceptive experiences as fluctuating and context-dependent, 11 often reflecting their struggles in interpreting bodily cues during times of emotional 12 stress or social pressure. Such subjective accounts further emphasize the need to 13 investigate interoceptive development through both quantitative and qualitative lenses. 14 Thus, to advance our understanding of interoception development, the current study 15 investigated multiple interoceptive dimensions during adolescence, analysing possible 16 differences from the adult pattern of development. To these aims, healthy adolescents, 17 whose ages ranged between 12 and 14 years, and adults, whose ages ranged between 18 25 and 34 years, performed a protocol that included measures of IAcc, ISe and IAw. 19 Adults in this age range represent an optimal comparison group, avoiding confounding 20 effects related to ageing processes. Indeed, several studies have suggested a regular 21 decline in several cognitive skills (e.g., speed of processing, working memory, and 22 long-term memory) starting from the 20s (see [24-26]), including interoceptive 23 processing (for an overview see [21]). 24 .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 6 1 Materials and Methods 2 Participants 3 Fifty-four typically developing adolescents (33 female participants, 21 male 4 participants; mean age = 13.3 years, SD =0.75, range 12-14 years) and fifty adults (24 5 female participants, 26 male participants; mean age = 27.7 years, SD = 2.6, range 25- 6 34 years) participated in this study. 7 A total of 50 adults and 54 adolescents were recruited based on sample sizes used in 8 previous studies (e.g.,[20]). Additionally, a sensitivity power analysis was performed 9 in G*Power 3.1.9.7 [27] for a two-sample t test, two-tailed, with α = .05 and desired 10 power = .80. The analysis showed that the study was powered to detect effects as small 11 as d = 0.56. Thus, any medium-to-large differences between adolescents and adults 12 should have been detectable. 13 All participants were native Italians from an urban context in southern Italy. 14 Adolescents were recruited from state schools in Calabria (Italy), while young adults 15 were recruited by word of mouth. 16 All recruited participants showed normal reasoning ability according to the Italian 17 norms of the Raven’s Colored Progressive Matrices (RCPM, [28,29]) or of Raven’s 18 Standard Progressive Matrices (RSPM, for participants aged from 12 to 13 years; 19 [30]) and had normal or corrected to normal vision and no history of neurological or 20 psychiatric conditions. 21 Before taking part in the study, all adult participants provided written informed 22 consent. Adolescents' assent was received before the investigation, and their parents 23 gave written informed consent. Participants were recruited between 9 April 2022 and 24 22 December 2023. The study was approved by the local ethics committee (Calabria .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 7 1 Region Ethical Committee, Catanzaro, Italy) in accordance with the criteria laid down 2 in the 1964 Declaration of Helsinki. 3 4 Behavioral Testing 5 Assessment of the Interoceptive Accuracy 6 A Heartbeat Monitoring Task (HMT) [31] was used to assess IAcc. Participants, 7 placed in a comfortable position, were invited to relax, close their eyes, and focus on 8 bodily sensations, and were told: "When you hear a voice say "go" start counting your 9 heartbeats silently; when you hear "stop", stop counting and tell me the exact number 10 of heartbeats you counted". They were also instructed not to move during the task and 11 not to perform physical manipulations that could facilitate the detection of the pulse 12 (for example, feeling the beat by testing the pulse). This task was repeated six times, 13 using, for the adult group, time intervals of 25, 35 and 45 seconds separated by two 14 standard rest periods of 20 seconds; shorter intervals of 15, 20 and 18 seconds were 15 used for the adolescents [32]. 16 To be sure that the instructions given to participants were clear, they were given a short 17 training interval (10 seconds). 18 Meantime, real heart activity was recorded using a Bluetooth heart rate monitor (Polar 19 Verity sense, Kempele, Finland), a mobile device that allows easy and non-invasive 20 recording. The heartbeat signals of each participant were recorded and, through 21 comparison with their count made by the participant, the IAcc was calculated. For each 22 trial, an accuracy score was derived (using the formula of Garfinkel et al. [9]): 1 - (|n 23 real beats - n counted beats|) / ((n real beats + n counted beats)/2). The accuracy scores 24 obtained were calculated as the average of the six trials, producing an average value .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 8 1 for each participant [33]. The inclusion of the reported values (n counted beats) within 2 the denominator prevented an overestimation of the accuracy of performance in people 3 who showed high variance, particularly when more heartbeats were reported than 4 recorded [9]. 5 At the end of the task, participants were asked, "In which part of your body did you 6 feel your heartbeat during the previous task?". Then, an image of a body map was 7 presented (adapted from [34]), and participants were asked to indicate the relevant 8 body areas by circling them. The image also includes a box above the head with the 9 label “nowhere”. Nine body districts were identified: head, right ear, left ear, neck, 10 chest, abdomen, right hand and wrist, left hand and wrist and legs; each body district 11 was assigned 1 when the participant indicated that a specific part associated with the 12 perception of the heartbeat. Zero was assigned to those body districts that were not 13 selected by the participants. 14 15 Assessment of the Interoceptive Awareness 16 IAw was assessed by the correlation between the measure of IAcc and the degree of 17 confidence in one’s ability to estimate the number of heartbeats in the HMT, expressed 18 by the participant at the end of each trial, on a scale from 0 to 10, where 0 indicated 19 “no perception of heartbeat” and 10 indicated “full perception of heartbeat” (for such 20 methodology see [9]). 21 22 Assessment of the Interoceptive Sensibility .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 9 1 ISe was evaluated considering measures targeting both momentary, state-like beliefs 2 (i.e., confidence ratings), and global, trait-like interoceptive beliefs (i.e., ISe 3 questionnaires; see [35]). 4 Specifically, for what attains the state-like beliefs, at the end of each HMT trial, the 5 participants rated their confidence in their perceived accuracy of response on a scale 6 from 0 to 10, where 0 indicated “no perception of heartbeat” and 10 indicated “full 7 perception of heartbeat”. The task included six trials, and a mean confidence score was 8 computed for each participant by averaging the confidence ratings across the six trials. 9 Participants also completed an ISe questionnaire. Specifically, adult participants 10 completed the Self-Awareness Questionnaire (SAQ; [36]), while adolescents 11 completed the SAQ-C, an adaptation of the SAQ for children and adolescents [37]. 12 The SAQ and the SAQ-C are self-report questionnaires composed of 35 items 13 developed specifically to evaluate the frequency of common body feelings. Both 14 versions have been validated in Italian. Items are clustered into two domains, one 15 related to visceral feelings (e.g., “I feel my heart beat in my ears”) and the other to 16 somatosensory feelings (e.g., “I feel my palms sweaty”). 17 Participants were asked to read each item carefully and to evaluate how often they 18 experienced the described sensation; responses were reported on a five-point Likert 19 scale ranging from never to always (0 = never; 1 = sometimes; 2 = often; 3 = very 20 often; 4 = always). The total score is given by the sum of the responses of all items, 21 providing a score range of 0 to 140. Higher scores indicate higher levels of ISe. 22 23 24 .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 10 1 Statistical analyses 2 To verify the normality of data distribution for accuracy scores, we used the Shapiro- 3 Wilk test. Given the non-normal distribution observed in experimental variables, such 4 as the score of the heartbeat monitoring task, and considering that the questionnaire 5 probing interoceptive sensibility (SAQ) used Likert-style response items, providing 6 ordinal data, non-parametric statistical analyses were performed. 7 Specifically, comparisons between the two age groups (adolescents: 12 to 14 years old 8 vs. adults: 25 to 34 years old) on IAcc, IAw and ISe scores were performed using the 9 Mann-Whitney U test. Effect sizes for Mann–Whitney U tests were reported using the 10 rank-biserial correlation coefficient r rb. 11 A Chi-squared test was applied to analyse which part of the body was most used during 12 the IAcc task. 13 Finally, correlation analyses were conducted to explore the relationship between 14 various interoceptive dimensions within the adolescent and young adult groups. 15 Specifically, Spearman’s correlations were performed to examine the associations 16 between IAcc (Heartbeat Monitoring Task), IAw and ISe (i.e., mean confidence in the 17 HMT and SAQ total score) scores within each age group. 18 19 Results 20 Descriptive statistics for IAcc, IAw and ISe measures are reported in Table 1. 21 Concerning IAcc, the Mann–Whitney U tests revealed only a marginal difference 22 between the group of adolescents and adults in counting their heartbeats (U = 1055, p 23 = .055; r rb = .22), with adults exhibiting numerically higher IAcc on average (see Table 24 1). Instaed, adolescents exhibited a statistically significantly lower metacognitive .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 11 1 awareness of their interoceptive ability compared to adults (U= 981, p= .033; r rb = .23). 2 Concerning the ISe, the Mann-Whitney U test showed a significant effect of age group 3 on both the SAQ (U= 843, p < .001; r rb =0.38) and on the average confidence in the 4 HMT ( U= 911, p = .004; r rb =0.33), with adolescents reporting significantly higher 5 scores than adults. 6 Correlation analyses showed no significant associations between the different 7 interoceptive dimensions in both age groups (for adolescents, see Table 2; for adults, 8 see Table 3). 9 Concerning the two ISe measures, we found no significant associations between the 10 SAQ and the confidence rating in the HMT, both in adolescents (ISe-SAQ and Ise- 11 confidance, r rho = .05, p= .517) and in adults (ISe-SAQ and Ise-confidance, rrho = .104, 12 p= .471). 13 A chi-squared goodness of fit test was performed separately for adolescents and adults 14 to examine which body parts were used most frequently during the IAcc task. 15 For adolescents, the distribution of selected body parts was significantly different from 16 a uniform distribution (χ²(9) = 146, p < .001). The most commonly used body part was 17 the chest (49.35%), followed by the right hand/wrist (14.29%) and the neck (10.39%). 18 A similar pattern emerged for adults, χ²(9) = 88.0, p < .001, with the chest again being 19 the most frequently selected body part (36.25%), followed by the right hand/wrist 20 (17.5%) and left hand/wrist (16.25%). 21 To compare the distribution of body part selection between the two age groups 22 (adolescent vs. adults), a Chi-squared test of independence was performed. Body-part 23 selection did not differ significantly across age groups (χ²(8) = 8.63, p = .374). This 24 suggests that the body parts used during the HMT was not significantly different 25 between adolescents and adults. .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 12 1 Table 1. Descriptive statistics for the interoceptive measures in the groups of 2 adolescents and adults 3 Note: HMT, Heartbeat monitoring task; SAQ, Self-Awareness Questionnaire. 4 5 6 7 8 Adolescent group Interoceptive Accuracy Interoceptive Awareness Interoceptive Sensibility HMT ACCURACY-CONFIDENCE CORRELATION SAQ CONFIDENCE- HMT Mean (SD) 0.36 (0.4) 0.002 (0.5) 44.8 (19) 7.53 (1.25) Min -Max -0.95 – 0.91 -1 – 0.96 12-94 4.8 – 10 Adult group Interoceptive Accuracy Interoceptive Awareness Interoceptive Sensibility HMT ACCURACY-CONFIDENCE CORRELATION SAQ CONFIDENCE- HMT Mean (SD) 0.50 (0.4) 0.24 (0.4) 33.3 (14.3) 6.57 (1.6) Min- Max -0.54 – 0.95 -0.86 – 0.97 10-73 2.50– 9.33 .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 13 1 Table 2. Spearman correlation coefficients between the interoceptive measures in 2 the adolescent group 3 Note: HMT, Heartbeat monitoring task; SAQ, Self-Awareness Questionnaire. 4 5 Table 3. Spearman correlation coefficients between the interoceptive measures in 6 the adult group 7 Note: HMT, Heartbeat monitoring task; SAQ, Self-Awareness Questionnaire. 8 9 10 Adolescent group Interoceptive Accuracy Interoceptive Awareness Interoceptive Sensibility HMT ACCURACY- CONFIDENCE CORRELATION SAQ CONFIDENCE- HMT Interoceptive Accuracy rrho p - -0.07 .62 -0.06 .68 0.18 .20 Interoceptive Awareness rrho p - - 0.16 .27 -0.04 .81 Adult group Interoceptive Accuracy Interoceptive Awareness Interoceptive Sensibility HMT ACCURACY- CONFIDENCE CORRELATION SAQ CONFIDENCE- HMT Interoceptive Accuracy rrho p - 0.17 .24 -0.26 .06 0.28 .05 Interoceptive Awareness rrho p - - -0.20 .17 -0.09 .55 .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 14 1 Discussion 2 The study examined interoceptive functioning across three distinct dimensions - 3 accuracy, sensibility and awareness - in adolescents, with a focus on potential 4 developmental differences when compared to adults. 5 While no significant group differences emerged in IAcc, there was a marginal trend 6 suggesting slightly better performance in adults. More robust was the difference in 7 IAw, with adults demonstrating significantly higher metacognitive insight into their 8 bodily signals. On the other hand, adolescents scored higher on both measures of ISe: 9 the SAQ and on confidence ratings during the heartbeat task. This pattern highlights a 10 dissociation between the subjective experience of bodily awareness and the 11 metacognitive ability to evaluate it. 12 The absence of a clear group difference in IAcc contrasts with previous findings by 13 Yang et al. [20], who reported a higher level of accuracy in adolescents. This difference 14 may be due to the broader age range of the adult sample by [20], which included 15 individuals into middle adulthood, where interoceptive accuracy is thought to decline. 16 By limiting our adult cohort to 25–34 years, we minimised this age-related confound 17 and found that heartbeat-counting accuracy is comparable across late adolescence and 18 early adulthood. Methodological differences (e.g., kind of task) may also have 19 contributed to the discrepant results. 20 Regarding IAw, the finding of lower metacognitive insight in adolescents is in line 21 with developmental models of metacognition (e.g., [38]) and supports the idea that 22 IAw matures later than the basic ability to detect bodily signals. Conversely, the higher 23 self-reported ISe in adolescents may reflect the heightened bodily attention 24 characteristic of adolescence due to pubertal changes [13] or psychosocial factors. This .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 15 1 finding is also interesting in light of studies that suggested that an exaggerated 2 interoceptive sensibility can be dysfunctional (see [11]). Indeed, this increased 3 tendency to notice internal bodily signals may be physiological, but can become fertile 4 ground for the onset of mental health disorders (e.g., anxiety and depression). 5 The lack of significant correlations between interoceptive dimensions in both age 6 groups replicates previous findings (for adolescents see [18]; for adults see [9]), and 7 lends further support to the three-dimensional model of interoception proposed by [9]. 8 Our data reinforce the idea that these dimensions are relatively independent and should 9 not be interpreted as reflecting a unified construct. 10 In our data, even within each age group, objective performance did not correlate with 11 subjective sensibility or metacognitive awareness, confirming that metacognitive or 12 subjective insight into internal states does not necessarily align with actual IAcc. This 13 underscores the need for a more nuanced approach when assessing interoceptive 14 abilities. 15 Additionally, our findings revealed no correlation between the two ISe measures, that 16 is, the SAQ scores and confidence ratings, within either group, in line with the idea 17 that these measures probe different ISe aspects [35]. Indeed, while the SAQ captures 18 a general, habitual focus on bodily signals, confidence ratings may reflect a 19 momentary, context-dependent judgment of interoceptive certainty [35]. In 20 developmental contexts, this is particularly relevant, as adolescents might report 21 increased general interoceptive sensibility due to physical and emotional changes, 22 without this necessarily translating into higher confidence in specific interoceptive 23 tasks. 24 Regarding body localisation during the IAcc task, both adolescents and adults most 25 frequently relied on the chest, followed by the wrists and neck. These patterns .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 16 1 significantly deviated from a uniform distribution, indicating consistent preferences 2 for certain bodily areas. However, the similarity between age groups in body part 3 selection suggests that both adolescents and adults use comparable perceptual 4 strategies when attending to internal sensations. This may reflect shared physiological 5 or conceptual representations of interoceptive cues, such as the heartbeat, regardless 6 of developmental stage. 7 Altogether, the findings contribute to a more comprehensive understanding of 8 interoception in adolescence. They indicate that while basic detection of bodily signals 9 may already be well established, the ability to reflect on or interpret these sensations 10 continues to develop. The observed mismatch between heightened bodily focus (ISe) 11 and lower metacognitive awareness (IAcc) in adolescents may have implications for 12 emotional processing and vulnerability to psychological distress. 13 Given the role of interoception in emotion regulation and psychopathology, these 14 results suggest that interventions aimed at adolescents could benefit from fostering the 15 ability to accurately evaluate and understand internal states. 16 Despite its contributions, this study has some limitations. The cross-sectional design 17 prevents us from inferring developmental trajectories, and our sample size, although 18 adequate, could be increased to improve statistical power. The validity of the HMT 19 has been questioned, as it may reflect participants’ estimation of their heart rate rather 20 than their actual ability to feel the heartbeats [39 – 41]. Also, our IAcc and IAw 21 measures exclusively targeted the cardiac modality. 22 Future studies should consider longitudinal designs and additional interoceptive 23 measures that consider different organ systems, including the cardiac, gastric, and 24 respiratory systems (for an overview, see [42]), to enhance our understanding of 25 interoceptive development. .CC-BY 4.0 International licensemade available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprintthis version posted August 3, 2025. ; https://doi.org/10.1101/2025.08.01.668055doi: bioRxiv preprint 17 1 References 2 1. Craig AD. How do you feel? Interoception: the sense of the physiological condition 3 of the body. 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