What’s Shared in Sharing Tasks and Actions? Processes and Representations Underlying Joint Performance

The last decade has seen a surge of interest in experimental studies of joint task performance. These studies have suggested that actors who share a single task not only perform it together, but also share a mental representation of the whole task; that is, actors represent both their and their co-actors portion of the task. Initial evidence supporting this proposal was garnered through the joint Simon task, wherein pairs of actors divide the work involved in performing a choice reaction task.

In the standard version of the Simon task with a single actor, response times are shorter when the responses spatially correspond to the location of stimuli (e.g., pressing a left key to circles on the left side of a computer monitor) than when they do not (pressing a left key to circles on the right). This Simon effect disappears if the task setting is altered in such a way that spatial attributes of stimuli or choice of responses are eliminated. For example, in a go/nogo version of the task, the actor responds to a type of stimulus (e.g., red circles) by pressing one key and withholds responding to another type of stimulus (green circles). The Simon effect disappears in this task context because only a single response is involved in the task, so the spatial attribute is no longer used to represent the response and there is no response conflict to resolve.

However, the Simon effect re-emerges when two actors perform the go/nogo version of the task together. In this joint Simon task, each co-actor operates one of the two response keys to respond to one type of stimulus, but ignore the other that is assigned to their partner. Critically, response times are still shorter if stimuli occur on the same side as the response location than if they occur on the opposite side. This finding was used to argue that co-acting individuals co-represent (or share a mental representation of) the task. The joint Simon effect has been replicated many times in different laboratories, and similar joint tasks have been tested (e.g., SNARC task, flanker task, Stroop task, inhibition of return, task-switching). Although many researchers have employed a co-representation approach to interpret their findings, others have raised doubt and offered alternative explanations.

The aim of this Research Topic is to assemble a collection of empirical findings and theoretical perspectives on the question of what co-actors share in joint action situations. The collection focuses particularly on neurocognitive processes and representations of joint action and performance. The scope encompasses such topics as, but not limited to, social attention, interpersonal interaction, automatic imitation, and self-agency, in healthy and special populations. This Research Topic will shed light on what lies beneath effective and ineffective collaborative actions among co-actors.