Let Your Eyes Predict

Abstract

This study investigates the prediction accuracy of anticipatory pupil dilation responses in humans prior to the random presentation of alerting or neutral sounds. The aim of this study was to test the hypothesis that the autonomous nervous system may react prior to the presentation of random stimuli. A total of 80 participants, who were matched according to gender to take into account individual differences, were asked to listen to a random sequence of 10 neutral and 10 alerting sounds. Their pupil dilation was continuously recorded and the diameter of their pupils was used to predict the category of sound, alerting, or neutral. The pupil dilation of both males and females predicted alerting sounds approximately 10% more accurately than would be expected by chance, whereas neutral sounds were predicted at the chance level. This result was confirmed using a frequentist and a Bayesian statistical approach. Following the results of the study, practical and theoretical implications of these results are discussed.