title: Referential coding does not rely on location features: Evidence for a nonspatial joint Simon effect.
abstract: The joint Simon effect (JSE) shows that the presence of another agent can change one's representation of one's task and/or action. According to the spatial response coding approach, this is because another person in one's peri-personal space automatically induces the spatial coding of one's own action, which in turn invites spatial stimulus-response priming. According to the referential coding approach, the presence of another person or event creates response conflict, which the actor is assumed to solve by emphasizing response features that discriminate between one's own response and that of the other. The 2 approaches often make the same predictions, but the spatial response coding approach considers spatial location as the only dimension that can drive response coding, whereas the referential coding approach allows for other dimensions as well. To compare these approaches, the authors ran 2 experiments to see whether a nonspatial JSE can be demonstrated. Participants responded to the geometrical shape of a central colored stimulus by pressing a left or right button, while wearing gloves of the same or different color as the stimuli. Participants performed the task individually, either by responding to either stimulus shapes (Experiment 1) or by responding to only 1 of the 2 shapes (Experiment 2), and in the presence of a coactor. Congruence between stimulus and glove color affected performance in the 2-choice and the joint tasks but not in the individual go/no-go task. This demonstration of a nonspatial JSE is inconsistent with the spatial response coding approach but supports the referential coding approach.
authors.affiliation: Institute for Psychological Research, Leiden University.
authors.forename: Roberta
authors.initials: R
authors.lastname: Sellaro
authors.affiliation: Research Group: Heterogeneity and Inclusion, Faculty of Human Science, University of Potsdam.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dolk
authors.affiliation: Institute for Psychological Research, Leiden University.
authors.forename: Lorenza S
authors.initials: LS
authors.lastname: Colzato
authors.affiliation: Institute for Psychology, University of Muenster.
authors.forename: Roman
authors.initials: R
authors.lastname: Liepelt
authors.affiliation: Institute for Psychological Research, Leiden University.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hommel
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult