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11:00 - 12:30
Parallel sessions 2
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11:00 - 12:30
Room: HSZ - N3
Chair/s:
Miriam Gade, Pamela Baess
The Simon effect – characterized by quicker responses when the location of the imperative stimulus corresponds to the position of the required response – has been recognized for decades (Simon, 1969) and is considered a valuable window into fundamental mechanisms of information processing. Simon effects have been found to vary depending on both spatial arrangement of stimuli and participants’ intentions, highlighting that the underlying cognitive processes are flexible and subject to modulation. Traditionally, Simon tasks are administered to individuals working in isolation, which does not reflect the inherently social nature of humans.
Therefore, this symposium spotlights the role of social information in modulating the Simon effect. Across four presentations and an integrative discussion, speakers will examine how agency attributions, perspective taking, and the presence of a co-actor influences performance in the Simon task. The findings will illuminate the social foundations of the classic Simon task.

Discussant: Roman Liepelt
Submission 611
Social Offloading in the Simon Task: Assigning Distractors to a Partner Reduces Interference
SymposiumTalk-02
Presented by: Anna K. Kuhlen
Miles Tufft 1, Anna K. Kuhlen 2
1 Department of Experimental Psychology, University College London, United Kingdom
2 Institute of Psychology, RWTH Aachen University, Germany
The Joint Simon task (Sebanz et al., 2003) is typically taken to show a default tendency to track others’ actions. We test how dividing task responsibilities modulates interference in the Joint Simon task. In the classic version, partners divide responsibility by assigning responses to one or the other target dimension in a go/no-go fashion. This division typically produces interference from the partner’s actions, consistent with the notion of partner co-representation. In contrast, a joint version of a related semantic compatibility task, the picture–word interference (PWI) task, shows that dividing responsibilities across targets and distractors (one person processes targets, the other distractors) can attenuate interference (Kuhlen & Abdel-Rahman, 2022; Tufft & Richardson, 2020). In this study (N = 48), we adopted that division-of-labor logic in the Simon task: participants responded to both target mappings while believing a co-actor handled the spatially defined distractors. Assigning responsibility for distractor processing to the partner eliminated the typical Simon interference. We interpret this reduction as social offloading: delegating distractor processing to a partner allows deprioritization of irrelevant spatial codes, facilitating more efficient action selection in distributed settings (cf. Tufft & Richardson, 2020). By reframing the Joint Simon task, we show how dividing responsibilities across partners can reveal when interference is sustained versus alleviated, offering a sharper view of the social foundations of the Simon effect.