Motor activation during observation of unusual versus ordinary actions in infancy

Abstract

Infants make predictions about actions they observe already during the first year of life. To investigate the role of the motor system in predicting the end state of observed actions, 12-month-old infants were shown movies of ordinary and extraordinary object-directed actions. The stimuli displayed a female actor who picked up an everyday object (a cup or a phone) and brought it to either her mouth or her ear. In this way, a similar movement could be ordinary (e.g., cup to mouth) or extraordinary (e.g., phone to mouth) depending on the object used. Infants' EEG and eye movements were recorded. We found a significantly stronger motor activation, indicated by a stronger desynchronization in the mu-frequency band over fronto-central areas, during observation of extraordinary compared to ordinary actions. This is explained within the computational framework of Kilner, Friston, and Frith (2007), who suggest that the motor system is used to generate predictions about actions we observe. If the observed action deviates from the initially expected path, additional predictions have to be generated, resulting in a stronger motor activation during perception of extraordinary actions. In sum, it appears that from early in life, the motor system is involved in making predictions about how an observed action will end.

Extrapolation and direct matching mediate anticipation in infancy

“…This would demand more from the responsible neural networks in that they are trying to process, predict, and learn from actions that the observer has no prior (physical) experience with. This interpretation is in line with studies that show greater activity in motor areas for less familiar actions (Stapel, Hunnius, van Elk, & Bekkering, 2010) as well as for highly familiar actions (van Elk, van Schie, Hunnius, Vesper & Bekkering, 2008). In terms of the present results, this interpretation suggests that the motor system will always activate when processing human actions.…”

What are you doing? How active and observational experience shape infants' action understanding

“…Mostly, neural markers that have been well established in adult research are implemented to investigate how infants process actions they observe [28][29][30]. Based on the idea that during action observation, an internal motor representation of that same behaviour within the observer is activated [31,32], many studies have focused on measuring activation of the infant's motor system during action observation.…”

Embodied Simulation of Others Being Touched in 1-Year-Old Infants

“…This is in line with previous work with 12-month-old infants (Stapel, Hunnius, Van Elk, & Bekkering, 2010). Infants' EEG data were included if at least 9 trials per condition met the following criteria: a) attention to the stimuli, b) no limb movements, and c) no EEG artefacts (e.g., eye blinks, electrode drifts).…”