The ability to recognize the emotional state of another person or persons is an important social skill. Moreover, efficient emotional perception determines the appropriate response action. Although many studies have investigated the processes involved in investigating the perception of emotion from individual facial expressions or body postures, very little is known about how we perceive emotions from a crowd of individuals. Furthermore, our understanding of how the visual and auditory senses combine to influence the perception of the emotion of a crowd is poor.
We previously found that the emotion conveyed by a crowd can be accurately determined using vision only and that the visual categorization of a crowd is efficient even when the emotion is not consistent across the individuals in the crowd. In the current study we investigated the role of auditory information on the perception of the visual emotion of the crowds. Our stimuli comprised of audio-visual dynamic displays of crowds of varying levels of emotional consistency, from highly consistent to ambiguous. The emotions expressed were anger, fear, happiness and sadness. The auditory emotional cue was paired with each visual display such that it was consistent with one of the emotions visually displayed. We used a 4-AFC design and the participant’s task was to categorise the visual emotion but to ignore the auditory information. We found that the auditory emotion significantly biased the perception of the emotion in the visual crowd, particularly when the emotion was visually ambiguous (e.g. half of the individuals in a crowd were fearful whereas the other half were sad). Our findings suggest that auditory emotional information can modulate the visual perception of the emotion of a crowd and have important implications for our understanding of emotional cognition.