Action plans used in action observation

Abstract

How do we understand the actions of others? According to the direct matching hypothesis, action understanding results from a mechanism that maps an observed action onto motor representations of that action. Although supported by neurophysiological and brain-imaging studies, direct evidence for this hypothesis is sparse. In visually guided actions, task-specific proactive eye movements are crucial for planning and control. Because the eyes are free to move when observing such actions, the direct matching hypothesis predicts that subjects should produce eye movements similar to those produced when they perform the tasks. If an observer analyses action through purely visual means, however, eye movements will be linked reactively to the observed action. Here we show that when subjects observe a block stacking task, the coordination between their gaze and the actor's hand is predictive, rather than reactive, and is highly similar to the gaze-hand coordination when they perform the task themselves. These results indicate that during action observation subjects implement eye motor programs directed by motor representations of manual actions and thus provide strong evidence for the direct matching hypothesis.

How do speakers coordinate? Evidence for prediction in a joint word-replacement task

“…There is substantial evidence that observers predict actions (Kilner, Vargaa, Duval, Blakemore, & Sirigu, 2004;Ramnani & Miall, 2004;Flanagan & Johansson, 2003;Graf et al, 2007;see Wilson & Knoblich, 2005 for a review). For example, the readiness potential, that indexes the preparation of motor responses, is present from about 500ms prior the observation of a predictable hand action (Kilner et al, 2004).…”

Simulating and predicting others’ actions

“…An increasing body of research suggests that people run internal simulations based on their own motor repertoire when predicting the future course of other people's actions (Blakemore & Frith, 2005;Kilner, Marchant, & Frith, 2009;Wilson & Knoblich, 2005). For instance, eye movements during action observation are predictive (Flanagan & Johansson, 2003;Rotman, Troje, Johansson, & Flanagan, 2006), and motor regions of the brain are engaged when participants must predict upcoming action events (Kilner, Vargas, Duval, Blakemore, & Sirigu, 2004;Stadler et al, 2011). Earlier findings from monkey neurophysiological work revealed activation of mirror neurons within premotor cortex when the monkeys observed the relevant phase of an observed grasping movement being occluded (Umiltà et al, 2001).…”

Motor execution affects action prediction

“…Humans seem to run internal sensorimotor simulations when predicting the future course of observed actions (see Sebanz & Knoblich, 2009;Wilson & Knoblich, 2005, for reviews). Flanagan and Johansson (2003) showed that eye movements during action observation were predictive rather than reactive, and Kilner, Vargas, Duval, Blakemore, and Sirigu (2004) found that motor-related brain activity occurred prior to observing a predictable movement. Furthermore, increased premotor activation was found when observers predicted the future course of partly invisible action sequences (Stadler et al, in press), indicating that internal simulation is used for action prediction.…”