Drawn together: When motor representations ground joint actions

Abstract

a b s t r a c tWhat enables individuals to act together? Recent discoveries suggest that a variety of mechanisms are involved. But something fundamental is yet to be investigated. In joint action, agents represent a collective goal, or so it is often assumed. But how, if at all, are collective goals represented in joint action and how do such representations impact performance? To investigate this question we adapted a bimanual paradigm, the circle-line drawing paradigm, to contrast two agents acting in parallel with two agents performing a joint action. Participants were required to draw lines or circles while observing circles or lines being drawn. The findings indicate that interpersonal motor coupling may occur in joint but not parallel action. This suggests that participants in joint actions can represent collective goals motorically.

Co-actors represent the order of each other’s actions

“…Acting alongside a co-actor was sufficient to trigger co-representation. Whereas this result is in line with earlier research on task co-representation (e.g., Sebanz et al, 2003 , Sebanz et al, 2005 ), it is less consistent with recent evidence demonstrating that co-actors need to conceive of their actions as joint to take each other’s actions into account ( della Gatta et al, 2017 ).…”

“…Again, this result pattern resembles findings earlier obtained in a bimanual version of the same task in which the limb without obstacle moved as if it were also clearing an obstacle ( Kelso, Putnam, & Goodman, 1983 ). Finally, della Gatta et al (2017 ) showed that when one person draws a line while the other draws a circle, the line trajectories tend to become ovalized. This corresponds to findings from the bimanual literature showing that the same interference occurs when drawing a circle with one hand while drawing a line with the other ( Franz, Zelaznik, & McCabe, 1991 ), indicating that the action representations of line and circle interfere with one another.…”

Can joint action goals reduce visuomotor interference effects from a partner’s incongruent actions?

“…For instance, it has been shown that under certain circumstances joint action goal representations can lead to an increase in this form of interference. In one study 15 This would be consistent with research showing the facilitatory effects of Lissajous plots on bimanual coordination 21,22 . In this research, participants are instructed to perform two separate rhythmic actions, one with each hand.…”

“…However, it does not appear to explain why the joint action frame would have reduced interference from physically incongruent movements. In principle, integrating representations of incongruent movements within a larger motor plan could have increased interference effects instead 15 . Figure 1: Two physically incongruent actions become part of a larger plan.…”

What's Shared in Movement Kinematics: Investigating Co-representation of Actions Through Movement

“…Recent literature suggests that common goals might not be fundamental for creating social interactions (Gallotti et al, 2017). At the same time, other evidence points to consider common goals at the heart of reciprocal motor influence (della Gatta et al, 2017). In order to disentangle these different perspectives, it could be useful to investigate, through the manipulation of the instructions, whether and how others' motor representations change as a function of the presence/absence of a common goal.…”