When two actors perform different tasks: Still no evidence for shared task-sets in joint task switching.

Motonori Yamaguchi,Bernhard Hommel,Husnain H Shah

doi:10.1177/17470218211031545

Motonori Yamaguchi, Bernhard Hommel + Show 1 more

Open Access

https://doi.org/10.1177/17470218211031545

Copy DOI

Abstract

Two different variations of joint task switching led to different conclusions as to whether co-acting individuals share the same task-sets. The present study aimed at bridging this gap by replicating the version in which two actors performed two different tasks. Experiment 1 showed switch costs across two actors in a joint condition, which agreed with previous studies, but also yielded even larger switch costs in a solo condition, which contradicted the claim that actors represent an alternative task as their own when it is carried out by the co-actor but not when no one carries it out. Experiments 2 and 3 further examined switch costs in the solo condition with the aim to rule out possible influences of task instructions for and experiences with the other task that was not assigned to the actor. Before participants were instructed on the second of the two tasks, switch costs were still obtained without a co-actor when explicit task names (“COLOUR” and “SHAPE”) served as go/nogo signals (Experiment 2), but not when arbitrary symbols (“XXXX” and “++++”) served as go/nogo signals (Experiment 3). The results thus imply that switch costs depend on participants’ knowledge of task cues being assigned to two different tasks, but not on whether the other task is performed by a co-actor. These findings undermine the assumption that switch costs in the joint conditions reflect shared task-sets between co-actors in this procedure.

Highlights

Numerous models and theories have been suggested to account for human performance in isolation but only little is known about how individuals perceive and act in the presence of, or in interaction with, other individuals (Knoblich & Sebanz, 2006)
The results showed task-switch costs (TSCs) when the preceding trial was performed by the same actor as the actor on the current trial, but they were abolished when the preceding trial was performed by a different actor than the current actor
Note that this finding of TSCs in the solo condition appears inconsistent with findings in many previous studies, in which TSCs were abolished after nogo trials (e.g., Lenartowicz et al, 2011; Schuch & Koch, 2003; Verbruggen et al, 2005), but Dudarev and Hassin’s procedure differed from those used in the previous studies: given that each participant performed only one of the two tasks, trials following nogo trials were always switch trials

Summary

Introduction

Numerous models and theories have been suggested to account for human performance in isolation but only little is known about how individuals perceive and act in the presence of, or in interaction with, other individuals (Knoblich & Sebanz, 2006) This lack of knowledge has, among other things, motivated studies in which individual performance in classical experimental tasks is compared with performance in conditions where the task is shared with a co-actor. The outcomes were comparable to those in a solo condition in which the actors performed a go/nogo procedure without a co-actor (Schuch & Koch, 2003) These results were replicated in subsequent studies (Yamaguchi et al, 2017a, 2019) and suggest that actors do not represent the task of their co-actor. Note that this finding of TSCs in the solo condition appears inconsistent with findings in many previous studies, in which TSCs were abolished after nogo trials (e.g., Lenartowicz et al, 2011; Schuch & Koch, 2003; Verbruggen et al, 2005), but Dudarev and Hassin’s procedure differed from those used in the previous studies: given that each participant performed only one of the two tasks, trials following nogo trials were always switch trials

Objectives

Methods

Results