Pupil mimicry in infants and parents

ABSTRACT

Changes in pupil size can reflect social interest or affect, and tend to get mimicked by observers during eye contact. Pupil mimicry has recently been observed in young infants, whereas it is unknown whether the extent and the speed of infants’ pupil mimicry response are identical to that of adults. Moreover, the question of whether pupil mimicry in infants is modulated by the race of the observed other remains to be explored. In two studies, pupil mimicry was investigated in infants and their parents. In the first study, 6-, 12- and 18-month-olds (n = 194) and their parents (n = 192) observed eyes with dynamically dilating, constricting, or static pupils. Infants mimicked the pupil sizes of the observed eyes like their parents, but responded slower. Study 2 replicated these findings in a new sample of infants (n = 55, 12-month-olds) and parents (n = 64), and further showed that the pupil mimicry response was not significantly modulated by the race of the observed partner neither in infants nor in parents. We conclude that pupil mimicry is an ancient bonding mechanism that helps to connect people.

KEYWORDS:

• Pupillometry
• synchronisation
• development
• infancy
• own-race bias

Acknowledgements

The authors are grateful to parents and infants who contributed to the study.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Data Availability

The data for the current study are available by request to the corresponding author.

Additional information

Funding

The contribution of Evin Aktar and Mariska E. Kret were supported by the Dutch National Science Foundation (Nederlandse Organisatie voor Wetenschappelijk Onderzoek, #016.Veni.195.285, #016.Vidi.185.036). The contribution of Mariska E. Kret was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 (H2020 European Research Council) Program for Research and Innovation Grant (#804582).