Assessing Deviations from Chance in a Spatial Guessing Task: Analytical Framework and Results from a Single Participant

Experimental parapsychology research has long examined whether individuals can identify hiddentargets without conventional sensory cues, typically using forced-choice or free-responseparadigms. This paper presents a computerized task in which participants attempt to guess thelocation of a hidden target on a screen, along with an analytical framework that evaluates whetherperformance exceeds chance. After describing the statistical approach, which uses a continuousmeasure of trial-wise response accuracy, we present data from a single participant whoseperformance was previously described as above chance in similar studies. Overall, performancedid not exceed chance; however, a trend toward higher accuracy, though not surviving correctionfor multiple comparisons, was observed in one condition. Subsequent analyses using Monte Carlosimulations indicated that subtle differences in the spatial distribution of the random targets partlyaccounted for this effect. We discuss how the present framework differs from conventional forced-choice guessing tasks and emphasize the importance of post hoc analyses for drawing validstatistical inferences.