Infants’ facial input from 6 to 17 months rarely includes hypothesized expressive emotion prototypes

The facial configurations that infants encounter in typical interactions with caregivers and family members form a basis for their understanding of emotion. Studies to date have described or quantified these natural exposures to facial information, but descriptions of the emotional content of that input are still needed. We accomplished this by leveraging an existing, longitudinal corpus of video-recordings of 6- to 17-month-old infants’ interactions with close others.

We found that infants were generally exposed to far more partial than full faces, and that exposure to full faces, while low, increased over the time periods observed. Exposure to facial configurations hypothesized to serve as expressive prototypes for categories of emotion (e.g., happiness, anger) was extremely rare. When hypothesized expressive prototypes did occur, it was often in unexpected contexts, suggesting that they did not necessarily serve as a cue to the presumed emotional meaning.

Lastly, descriptive analyses of the facial movement data revealed that infants’ input was dominated by a few, mostly simple facial configurations that did not correspond fully or uniquely to hypothesized category prototypes. These results extend evidence that emotions are expressed heterogeneously in daily life, such that infants must learn much more than one-to-one mappings between facial configurations and context/behavior to acquire expressive vocabularies for emotion. Elika Bergelson for sharing the SEEDLingS data set with our research group.

V.L. was supported by the National Science Foundation Grant #2333886 and the Eunice Kennedy Shriver National Institute of Child Health and Human Development Grant 1R21HD112313-01A1. L.F.B. was supported by the Unlikely Collaborators Foundation. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Department of Psychology, University of Kansas, Lawrence, KS, USA Department of Psychology, Rutgers University, Newark, NJ, USA Marissa Ogren, Lauren Leotti & Vanessa LoBue Department of Psychology, Northeastern University, Boston, MA, USA Psychiatric Neuroimaging Division, Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA Center for Mind and Brain, University of California at Davis, Davis, CA, USA Department of Psychology, University of California at Davis, Davis, CA, USA The authors declare no competing interests. Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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