Poster A12, Saturday, March 24, 1:30–3:30 pm, Exhibit Hall C
Sexually Dimorphic Pupillary Responses During Facial Trustworthiness Evaluation: A Study With Intranasal Oxytocin Administration
Fatma Gülhan Saraçaydın1, Didem Gökçay1; 1Middle East Technical University
It has been shown that oxytocin (OT) increases the trusting behavior in humans. In this study, we focused on the role of OT on processing of facial trustworthiness. We aimed to investigate the effects of OT on trustworthiness evaluation and associated pupil dilation. Possible sexual dimorphisms and physiological differences were also subject of interest. In a double-blind between-subjects design, 12 males and 12 females received either 24 IU intranasal OT or placebo (PLC). The participants were required to evaluate trustworthiness of face images with neutral expression. Ratings were collected along a 1 to 9 scale (1: not at all trustworthy; 9: very trustworthy). Changes in pupil diameter were assessed using the TOBII T120 eye-tracker. Intranasal OT resulted in an increase in trustworthiness ratings for both sexes (p< 0.001). However, the effect of OT supported sexual dimorphism in physiology: males receiving intranasal OT showed increased changes in pupil diameter (p=0.033) whereas the reverse situation was observed for females (p<0.001). Independent from the application of intranasal OT/PLC, participants exhibited largest pupil diameters for untrustworthy faces, and smallest pupil diameters for neutral faces (p<0.001). To the best of our knowledge, this is the first study that investigates the relationship between trustworthiness evaluation, task-evoked pupillary responses, and the effect of intranasal OT in both sexes. The results verify our current knowledge regarding OT’s crucial role in trusting behavior in humans, and our findings in physiological responses might open new research questions regarding the pivotal role of OT in prosocial behavior.
Topic Area: EMOTION & SOCIAL: Emotion-cognition interactions