Figure 1.
Examples of the four combinations ‘grip intention’ that participants encountered during the experiment, and that lead to ‘optimal’ or ‘suboptimal’ behaviors.
All combinations began with the demonstrator's static hand. The actor could then use either a ‘power’ or a ‘precision’ grip to achieve either the intention of Opening the box (O) or Switching the lights on (S). The combination between the kind of grip and the kind of final intention resulted in the complete action as being labeled biomechanically optimal (OPTIMAL) or suboptimal (SUBOPTIMAL). Whereas the complete action movies lasted until the achievement of the underlying intention for a total duration of 2000 msec, the incomplete action movies stopped 800 msec after the movement onset (when the demonstrator was about to grasp the tool) while the last displayed frame remained on the screen for a duration of 1200 msec, so that observers had information about the grip but no information (on that trial) about the demonstrator's intention.
Figure 2.
a) and c) represent the mean percentages of correct responses collected during complete and incomplete action movies for all three sessions. b) and d) represent the mean response times collected during complete and incomplete action movies for all three sessions. The green columns refer to the mean percentages of correct predictions for observed ‘optimal’ behaviors (pooled across ‘power’ and ‘precision’ grip). The orange columns refer to the mean percentages of correct predictions for observed ‘suboptimal’ behaviors (pooled across ‘power’ and ‘precision’ grip). Error bars denote the standard error of the mean.
Figure 3.
a) and b) represent the mean percentages of correct responses collected during complete and incomplete action movies for all three sessions. The green columns refer to the mean percentages of correct predictions for ‘optimal’ behaviors (pooled across ‘power’ and ‘precision’ grip). The orange columns refer to the mean percentages of correct predictions for ‘suboptimal’ behaviors (pooled across ‘power’ and ‘precision’ grip). Error bars denote the standard error of mean.