Observer-Agent Kinematic Similarity Facilitates Action Intention Decoding

Abstract

it is well known that the kinematics of an action is modulated by the underlying motor intention. in turn, kinematics serves as a cue also during action observation, providing hints about the intention of the observed action. However, an open question is whether decoding others' intentions on the basis of their kinematics depends solely on how much the kinematics varies across different actions, or rather it is also influenced by its similarity with the observer motor repertoire. The execution of reach-to-grasp and place actions, differing for target size and context, was recorded in terms of upper-limb kinematics in 21 volunteers and in an actor. Volunteers had later to observe the sole reach-to-grasp phase of the actor's actions, and predict the underlying intention. The potential benefit of the kinematic actorparticipant similarity for recognition accuracy was evaluated. In execution, both target size and context modulated specific kinematic parameters. More importantly, although participants performed above chance in intention recognition, the similarity of motor patterns positively correlated with recognition accuracy. Overall, these data indicate that kinematic similarity exerts a facilitative role in intention recognition, providing further support to the view of action intention recognition as a visuo-motor process grounded in motor resonance.

Efficacy and Characteristics of the Stimuli of Action Observation Therapy in Subjects With Parkinson's Disease: A Systematic Review

“…Moreover, the brain response to observation of actions has been demonstrated to be influenced by personal motor repertoire, revealing greater MNS activity when the observed actions belong to motor expertise of observers (66,67). In addition, activity of the MNS seems to be modulated not only by the previous acquisition of motor skills (motor repertoire) but also by the visual familiarity with observed actions (visual practice) (68,69), where the similarity of the observed kinematics with the observer's own kinematics seems to enhance the resonance of motor brain areas (70,71).…”

Neurotypical individuals fail to understand action vitality form in children with autism spectrum disorder

“…On the one side, atypical kinematics in movement execution has been shown to be linked in ASD individuals to difficulty not only in categorizing biological movements ( 44 ), but also in identifying the motor intention underlying the observed action ( 47 – 52 ). On the other side, neurotypical individuals have been shown to be better in predicting the outcome of observed actions when these actions are kinematically similar to their own ( 53 – 56 ). Furthermore, skilled individuals outperform novices when asked to recognize observed actions, with motor expertise impacting on action understanding even in absence of a corresponding visual expertise ( 57 , 58 ).…”

Dancing in Your Head: An Interdisciplinary Review

“…The studies cited so far offer an important contribution in this research field and are well-known studies on action observation. Recently (De Marco et al, 2020 , p. 2) underlined how “observing motorically ‘familiar‘ actions relative to the own motor expertise determined a greater mirror motor activation (i.e., stronger motor resonance) and finer action prediction capability with respect to what happens while observing ‘unfamiliar‘ actions.” They considered other aspects beyond the classical conceptualization of the observation of the action, such as the kinematic characteristics of the movement (Hasson and Frith, 2016 ). As mirror neurons play an important role in the in understanding others' intentions (see for example Iacoboni, 2005 ; Gergely and Csibra, 2008 ; Ruggiero and Catmur, 2018 ) and also in clinical diseases (see for example Palermo et al, 2020 ).…”