Pupil dilation and infant cognition

Looking time data provide the main window into early cognitive abilities of human infants. With respect to advanced conceptual capabilities, research findings supporting such skills in infants using Violation-of-Expectations (VOE) methods have been met with sustained criticism. This paper proposes the introduce pupil dilation data as a complement to looking time measures. Pupil dilation is an autonomous response to arousal, and should be observed if and when infants are surprised by conceptually unusual events, as typically used in VOE tasks. This paper reports on analyses of pupil dilation data to VOE events involving an implausible change of object identity. The data show that while some aspects of pupil responses show fluctuations across trials, some important features that help in the interpretation looking time data remain stable. The discussion stresses the potential benefits of including pupil data analyses in the study of infant cognition.