Emotion matters: Face ensemble perception is affected by emotional states.

Ensemble coding is the ability of the visual system to extract a summary statistic from a set of stimuli. For example, observers often spontaneously extract an average face identity from a set of faces. Ensemble coding is known to operate in the frame of a distributed/global attention model. Because both attention and holistic processing are modulated by emotion - where positive emotions broaden the scope of attention and facilitate global processing, whereas negative emotions narrow the scope of attention and promote local processing - the current research explored whether emotional states could affect visual averaging of multiple face identities. Participants completed an ensemble-coding task before and after their emotion was induced via film clips. In the ensemble-coding task, a set of four face identities was shown briefly, followed by a probe face. Participants judged whether the probe face was presented in the preceding set. Evidence for ensemble coding was indexed by responses that treated an average face of the preceding set as a member of that set. The results showed that the tendency to choose this average was modulated by emotional states. Visual averaging increased after seeing positive film clips, but decreased after seeing negative film clips. These results support Frederickson's broaden-and-built theory, and extended its application to ensemble perception.