The shared signal hypothesis: effects of emotion-gaze congruency in infant and adult visual preferences.

In this study, 4-month-old infants' and adults' spontaneous preferences for emotional and neutral displays with direct and averted gaze are investigated using visual preference paradigms. Specifically, by presenting two approach-oriented emotions (happiness and anger) and two avoidance-oriented emotions (fear and sadness), we asked whether the pattern of emotion-gaze interaction suggested by the shared signal hypothesis (SSH) would also be found with this paradigm. Both age groups demonstrated an ability to discern the approach- and avoidance-oriented emotions, matching them with direct and averted gaze, respectively. Nonetheless, infants showed a greater sensitivity for the congruent emotion-gaze combination in the approach-oriented emotions, while adults were equally sensitive to the gaze-expression congruence for both the approach- and avoidance-oriented emotions. In a follow-up experiment, infants showed no preference for direct or averted gaze in the context of neutral faces. We conclude that the SSH may have validity from infancy, gradually extending from approach-oriented emotions to avoidance-oriented emotions over the course of development.