Kinematics fingerprints of leader and follower role-taking during cooperative joint actions

Abstract

Performing online complementary motor adjustments is quintessential to joint actions since it allows interacting people to coordinate efficiently and achieve a common goal. We sought to determine whether, during dyadic interactions, signaling strategies and simulative processes are differentially implemented on the basis of the interactional role played by each partner. To this aim, we recorded the kinematics of the right hand of pairs of individuals who were asked to grasp as synchronously as possible a bottle-shaped object according to an imitative or complementary action schedule. Task requirements implied an asymmetric role assignment so that participants performed the task acting either as (1) Leader (i.e., receiving auditory information regarding the goal of the task with indications about where to grasp the object) or (2) Follower (i.e., receiving instructions to coordinate their movements with their partner's by performing imitative or complementary actions). Results showed that, when acting as Leader, participants used signaling strategies to enhance the predictability of their movements. In particular, they selectively emphasized kinematic parameters and reduced movement variability to provide the partner with implicit cues regarding the action to be jointly performed. Thus, Leaders make their movements more "communicative" even when not explicitly instructed to do so. Moreover, only when acting in the role of Follower did participants tend to imitate the Leader, even in complementary actions where imitation is detrimental to joint performance. Our results show that mimicking and signaling are implemented in joint actions according to the interactional role of the agent, which in turn is reflected in the kinematics of each partner.

Frontal alpha oscillations distinguish leaders from followers: Multivariate decoding of mutually interacting brains

“…Leader-follower dynamics have been investigated in behavioural studies before (Noy et al, 2011, Sacheli et al, 2013, Wing et al, 2014, and previous work on agency has addressed the roles of imitators (i.e. followers) and initiators (i.e.…”

“…It has been shown that both symmetrical and complementary motor adaptation of interacting partners is used when working toward a common goal (Kokal et al, 2009, Masumoto and Inui, 2013, Sacheli et al, 2013. However, the neural mechanisms underlying interpersonal real-time coordination remain largely unknown, as the methodological frameworks to study them have been underdeveloped Roepstorff, 2012, Hari et al, 2013).…”

Interactional leader–follower sensorimotor communication strategies during repetitive joint actions

“…This model M6 takes into account the value of the variable A t at the same trial t of L t (table 2). Results showed no significant main effect of baseline session (baseline1 versus baseline2) [F (1,14) ¼ 1.130, p ¼ 0.306], indicating participants achieved the same level of performance in baseline1 and baseline2. Thus, we averaged the two sessions and used their mean to normalize (i.e.…”

“…This analysis showed a main effect of test session [F (1,14) Given our specific hypotheses of signalling and imitation regarded the comparison between test1 and test2, the kinematic analyses were performed only on these two sessions. Table 1.…”

“…In this perspective, the asymmetric allocation of information between two partners (e.g. leader-follower) is known to shape the kinematics of their movements [14,[17][18][19][20][21]. Role assignment gives the agents the possibility to support coordination by implementing so-called signalling strategies [22,23], for example by systematically making the trajectory of their movements less variable and hence more predictable [14,24,25].…”