Williams A, Gribble PL. Observed effector-independent motor learning by observing. J Neurophysiol 107: 1564 -1570, 2012. First published December 21, 2011 doi:10.1152/jn.00748.2011pelling idea in cognitive neuroscience links motor control and action observation. Recent work supports the idea that a link exists not just between action observation and action planning, but between observation and motor learning. Several studies support the idea that cortical regions that underlie active motor learning also play a role in motor learning by observing. The goal of the present study was to test whether motor learning by observing is effector dependent (as in active motor learning) or effector independent (as in studies of action observation and mirror neurons). Right-handed human subjects observed a video depicting another individual learning to reach to visual targets in a force field (FF). The video showed reaching in a clockwise FF (CWFF) or a counter-clockwise FF (CCWFF), and depicted an individual reaching with the right or left arm. After observation, all subjects were asked to reach in a CWFF, using their right arm. As in our prior studies, subjects who observed a CWFF prior to the CWFF test performed better than subjects who observed a CCWFF. We show here that this effect was seen both when observers watched others reach using their right arm, and when observers watched others learning to reach using the left arm. These results suggest that information about novel forces learned through observation is represented in an effector-independent coordinate frame, and are consistent with the idea that the brain links not only observation and movement, but motor learning as well, through abstract representations of actions.

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We compare two alternative measures for assessing people’s emotional reactions to political stimuli: the traditional self-report measure and facial expression analysis. We recruited participants to take part in a study examining reactions to a set of negative political commercials aired during the 2018 elections. We compare people’s self-reporting of their emotional reactions to negative political advertisements with their expressed emotion, according to the facial expression analysis. We find the discriminant validity of the facial expression analysis is higher than the self-report measure. Second, the self-report and facial expression measures of emotion have little convergent validity: we fail to find a consistent and strong positive correlation between the self-report and facial software measures of the same emotion and the same political advertisement. Third, the facial software measure has better predictive validity than the self-report measure, generating better predictions for the three dependent variables examined: changes in political interest, changes in people’s confidence in elected officials, and people’s assessment of the tone of the senate campaign.