Looking into your eyes: observed pupil size influences approach-avoidance responses

Abstract

The eyes reveal important social messages, such as emotions and whether a person is aroused and interested or bored and fatigued. A growing body of research has also shown that individuals with large pupils are generally evaluated positively by observers, while those with small pupils are perceived negatively. Here, we examined whether observed pupil size influences approach-avoidance tendencies. Participants performed an Approach-Avoidance Task using faces with large and small pupil sizes. Results showed that pupil size influences the accuracy of arm movements. Specifically, individuals were less prone to approach a face with small pupils than a face with large pupils. Conversely, participants were less prone to avoid a face with large pupils than a face with small pupils. Collectively, these findings suggest that perceivers attend to a facial cue - pupil size - when interacting with others.

Pupils say more than a thousand words: Pupil size reflects how observed actions are interpreted

“…First, different studies demonstrated that eye-related cues are spontaneously considered when acting with a partner (De Stefani, Innocenti, Secchi, Papa, & Gentilucci, 2013;Ferri et al, 2011;Innocenti et al, 2012;Quesque & Coello, 2014). Second, recent works have shown that humans may use others' pupil changes to produce adaptive responses, without any training, when explicitly informed about their importance (Naber, Stoll, Einhäuser, & Carter, 2013) but also spontaneously in the absence of any instruction (Brambilla, Biella, & Kret, 2018;Kret & de Dreu, 2017;Kret et al, 2015;Van Breen et al, 2018). Whether potential partners may interpret high level social information as subtle as the one reported in the current study and adapt their behavior in response is however unknown and represent avenue for future research.…”

The power of pupils in predicting conforming behavior

“…In a seminal paper, Hess (1965) revealed that male individuals liked women with large pupils better than women with small pupils. In a similar vein, it has been shown that people are more willing to interact when partners have large rather than small pupils (Brambilla et al, 2019). Moreover, individuals with large pupils are judged to be sociable, and trustworthy, and those with small or constricting pupils cold, and untrustworthy (Kret & De Dreu, 2017;Kret, Fischer, & De Dreu, 2015).…”

“…To manipulate pupil size, we created two stimuli (see Figure 1): in one the image had pupils 40% larger than the standard pupil. In the second, the image had pupils 40% smaller than the standard pupil (see Brambilla et al, 2019;Kret et al, 2015).…”

“…Accordingly, there is good reason to expect that subtle variations in pupil size could alter conforming behavior. Combining research showing that conformity increases when the source of influence is liked (Carraro & Castelli, 2010;Paladino et al, 2010;Vaes et al, 2003) with findings showing that individuals with large pupil sizes are trusted and perceived positively (Brambilla et al, 2019;Hess, 1965;Kret & De Dreu, 2017;Kret et al, 2015), we expect that people would conform more strongly toward individuals with large pupils. We tested this prediction in two studies where we measured conformity toward a social target with different pupil size.…”

“…Moreover, a number of studies have examined how pupil size is interpreted, revealing that those with large pupils are generally perceived positively by their interaction partners (Brambilla, Biella, & Kret, 2019;Hess, 1965;Kret & De Dreu, 2017). In a seminal paper, Hess (1965) revealed that male individuals liked women with large pupils better than women with small pupils.…”