Adult judgments and fine-grained analysis of infant facial expressions: Testing the validity of a priori coding formulas.

Abstract

Three studies tested whether infant facial expressions selected to fit Max formulas (Izard, 1983) for discrete emotions are recognizable signals of those emotions. Forced-choice emotion judgments (Study 1) and emotion ratings (Study 2) by naive Ss fit Max predictions for slides of infant joy, interest, surprise, and distress. But Max fear, anger, sadness, and disgust expressions in infants were judged as distress or as emotion blends in both studies. Ratings of adult facial expressions (Study 2 only) fit a priori classifications. In Study 3, we coded the facial muscle components of faces shown in Studies 1 and 2 with the Facial Action Coding System (FACS; Ekman & Friesen, 1978) and Baby FACS (Oster & Rosenstein, in press). Only 3 of the 19 Max-specified expressions of discrete negative emotions in infants fit adult prototypes