title: Processing of Individual Items during Ensemble Coding of Facial Expressions.
abstract: There is growing evidence that human observers are able to extract the mean emotion or other type of information from a set of faces. The most intriguing aspect of this phenomenon is that observers often fail to identify or form a representation for individual faces in a face set. However, most of these results were based on judgments under limited processing resource. We examined a wider range of exposure time and observed how the relationship between the extraction of a mean and representation of individual facial expressions would change. The results showed that with an exposure time of 50 ms for the faces, observers were more sensitive to mean representation over individual representation, replicating the typical findings in the literature. With longer exposure time, however, observers were able to extract both individual and mean representation more accurately. Furthermore, diffusion model analysis revealed that the mean representation is also more prone to suffer from the noise accumulated in redundant processing time and leads to a more conservative decision bias, whereas individual representations seem more resistant to this noise. Results suggest that the encoding of emotional information from multiple faces may take two forms: single face processing and crowd face processing.
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of SciencesBeijing, China; University of Chinese Academy of SciencesBeijing, China.
authors.forename: Huiyun
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Experimental Clinical and Health Psychology, Ghent University Ghent, Belgium.
authors.forename: Luyan
authors.initials: L
authors.lastname: Ji
authors.affiliation: Department of Psychology, University of South Florida, Tampa FL, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Tong
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of SciencesBeijing, China; University of Chinese Academy of SciencesBeijing, China.
authors.forename: Naixin
authors.initials: N
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Psychology, Bournemouth University Poole, UK.
authors.forename: Chang Hong
authors.initials: CH
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Fu
keywords: diffusion model; emotion; ensemble representation; facial expression; individual representation; processing resource