title: Seeing the Big Picture: Size Perception Is More Context Sensitive in the Presence of Others.
abstract: This paper tests the hypothesis that social presence influences size perception by increasing context sensitivity. Consistent with Allport's prediction, we expected to find greater context sensitivity in participants who perform a visual task in the presence of other people (i.e., in co-action) than in participants who perform the task in isolation. Supporting this hypothesis, participants performing an Ebbinghaus illusion-based task in co-action showed greater size illusions than those performing the task in isolation. Specifically, participants in a social context had greater difficulty perceiving the correct size of a target circle and ignoring its surroundings. Analyses of delta plot functions suggest a mechanism of interference monitoring, since that when individuals take longer to respond, they are better able to ignore the surrounding circles. However, this type of monitoring interference was not moderated by social presence. We discuss how this lack of moderation might be the reason why the impact of social presence on context sensitivity is able to be detected in tasks such as the Ebbinghaus illusion.
authors.affiliation: Department of Social and Organizational Psychology, ISPA- Instituto Universitário, Lisbon, Portugal.|William James Center of Research, ISPA-IU, Lisbon, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Garcia-Marques
authors.affiliation: Department of Social and Organizational Psychology, ISPA- Instituto Universitário, Lisbon, Portugal.|William James Center of Research, ISPA-IU, Lisbon, Portugal.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fernandes
authors.affiliation: Department of Social and Organizational Psychology, ISCTE-Instituto Universitário de Lisboa, Lisbon, Portugal.|Centro de Investigação e Intervenção Social-Instituto Universitário de Lisboa (Cis-IUL), Lisbon, Portugal.
authors.forename: Marília
authors.initials: M
authors.lastname: Prada
authors.affiliation: William James Center of Research, ISPA-IU, Lisbon, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fonseca
authors.affiliation: Faculdade de Psicologia da Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Hagá
mesh_terms: D000704:Analysis of Variance; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009903:Optical Illusions / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011581:Psychological Tests; D011897:Random Allocation; D012858:Size Perception / Q000502:physiology*; D012919:Social Behavior; D012931:Social Environment; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult