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.

KEYWORDS:

• Pupil size
• approach
• avoidance
• social cognition
• eye signals

Acknowledgments

M. Brambilla, M. Biella, and M. Kret conceived the study idea. M. Brambilla and M Biella ran the study. M. Biella conducted the data analysis. M. Brambilla drafted the first version of the manuscript, while M. Biella and M. Kret read and commented on it.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Marco Brambilla http://orcid.org/0000-0002-4774-3309

Marco Biella http://orcid.org//0000-0002-8039-0170

Mariska E. Kret http://orcid.org/0000-0002-3197-5084

Notes

1 We considered only the left eye, as the pilot study (supplementary materials) did not reveal any effect of the side of the square (left vs. right) on the task by pupil size interaction. Moreover, additional data collected in our Lab (N = 77; unpublished) revealed that the social implications of pupils size tend to be better captured when the left side of the visual field is taken into account.

2 Preliminary analyses revealed that the approach-avoidance task as a function of pupil size was not influenced by the block (p = .42).