Pupillary contagion is independent of the emotional expression of the face.

The concept of pupillary contagion refers to the automatic imitation of observed pupil size and reflects shared autonomic arousal. Previous studies have linked the experience of sadness to changes in pupil size. Accordingly, in a 2006 Social Cognitive and Affective Neuroscience article, Harrison, Singer, Rotshtein, Dolan, and Critchley found evidence for pupillary contagion when the observed face expressed sadness but not when it showed a neutral, happy, or angry expression. However, differences in eye movements might have influenced these results. Furthermore, the relatively small sample size of the study merits additional replication. In the current study, we modified the experimental design of Harrison et al. by requiring high attention toward the eye region of the face, which minimized differences in eye movements between facial expressions. In doing so, we demonstrate that the degree of pupillary contagion is independent of the observed emotional expression. Instead, pupil size and emotional expression of the shown face independently contribute to the observer's pupil size. The role of pupillary contagion for social communication is discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).