Doing It Your Way: How Individual Movement Styles Affect Action Prediction

Abstract

Individuals show significant variations in performing a motor act. Previous studies in the action observation literature have largely ignored this ubiquitous, if often unwanted, characteristic of motor performance, assuming movement patterns to be highly similar across repetitions and individuals. In the present study, we examined the possibility that individual variations in motor style directly influence the ability to understand and predict others’ actions. To this end, we first recorded grasping movements performed with different intents and used a two-step cluster analysis to identify quantitatively ‘clusters’ of movements performed with similar movement styles (Experiment 1). Next, using videos of the same movements, we proceeded to examine the influence of these styles on the ability to judge intention from action observation (Experiments 2 and 3). We found that motor styles directly influenced observers’ ability to ‘read’ others’ intention, with some styles always being less ‘readable’ than others. These results provide experimental support for the significance of motor variability for action prediction, suggesting that the ability to predict what another person is likely to do next directly depends on her individual movement style.

Your move or mine? Music training and kinematic compatibility modulate synchronization with self- versus other-generated dance movement

“…While at first sight this result seems at odds with the simulation hypothesis, a few reasons need to be considered to explain the lack of a direct self advantage: One critical difference in the present study, as compared to Keller et al (Keller et al 2007), is that we explicitly minimized the presence of intentional timing deviations in the stimuli through recruitment of non-experts and the performance of paced movements. As opposed to highly skilled experts whose (unpaced) actions are a result of precisely controlled motor sequencing, e.g., the expressive timing in musicians (Repp and Knoblich 2004) or the well-practiced choreograph in dancers (Calvo-Merino et al 2005), non-experts who have just learned the dance stepsperformed while being pacedlikely produced more unintended spatiotemporal variability in their movement (Koul et al 2016). That is, the individual timing cues were largely unintentional.…”

“…As the musicians in these cases played without a metronome, the rhythm they produced contained intentional idiosyncratic temporal deviations from a prescribed underlying periodicity, which were critical cues for simulation. Here we asked whether a similar advantage in synchronizing with self-generated stimuli would also generalize to actions without such intentional deviations, given that individual motor styles in everyday movementsalbeit unintendedcan already modulate action prediction (Koul et al 2016). Could unintentional timing deviations in the movement lead to a "self advantage" in synchronization?…”

Considering context and variability when observing other minds

“…Becchio and colleagues have previously shown [8] that there are considerable individual differences in action kinematics for the same action across actors. In other words, the mapping from a particular kinematic feature to a particular intention is not constant across actors.…”

Transient disruption of the inferior parietal lobule impairs action mindreading

“…A major difficulty in studying action mindreading is the ever-changing nature of movement kinematics 10,11 . Movement is “repetition without repetition” 12 .…”