Linking differences in action perception with differences in action execution

Abstract

Successful human social interactions depend upon the transmission of verbal and non-verbal signals from one individual to another. Non-verbal social communication is realized through our ability to read and understand information present in other people's actions. It has been proposed that employing the same motor programs, we use to execute an action when observing the same action underlies this action understanding. The main prediction of this framework is that action perception should be strongly correlated with parameters of action execution. Here, we demonstrate that subjects' sensitivity to observed movement speeds is dependent upon how quickly they themselves executed the observed action. This result is consistent with the motor theory of social cognition and suggests that failures in non-verbal social interactions between individuals may in part result from differences in how those individuals move.

Keywords: action observation; action perception; mirror neurons; movement disorders; perception deficits.

Fig. 1

Through the whole figure blue shows data from the young healthy controls, red the movement disorder patients and green the age matched healthy controls. (a) shows the relationship between observed movement speed and relative change in inferred confidence. The black dots show the actual confidence of the person being observed and the grey line shows the linear fit of this data. Note that the data for each subject was mean corrected prior to averaging. (b) show the average sensitivity to the observed movement speed for the different groups. (c) shows the average movement speed of the subjects during action execution. (d) show the correlation of the execution time against observed movement sensitivity for all subjects. The black line shows that the results of a linear regression between these two variables. All error bars are standard errors of the mean. *, indicate significant differences at P < 0.05.

Fig. 2

Through the whole figure blue shows data from the young healthy controls, red the movement disorder patients and green the age matched healthy controls. (a) show the average sensitivity to the observed movement speed for the different groups. (b) shows the correlation of the execution time against observed movement sensitivity for all subjects. The black line shows that the results of a linear regression between these two variables (c) show the correlation of estimated time of dot reappearance and actual time of dot reappearance for all three groups. (d) shows the average slope of the regression between actual time of reappearance and estimated time of reappearance for each subject in the different groups. (e) shows the average sensitivity to the observed movement speed and the observed movement speed for the different groups. Note that this data has been normalized prior o plotting such that the mean was equal to one and the standard deviation equal to one. All error bars are standard errors of the mean. *, indicate significant differences at P < 0.05.