Abstract

In our daily lives, we gather a broad range of information about other agents by watching them move. A considerable body of research has been dedicated to understanding how the human brain makes sense of other agents in motion. Findings from work carried out with human and non-human primates implicate the involvement of parietal, premotor and occipitotemporal regions in automatic matching processes that link action with perception. Moreover, the consensus view is that these brain regions are biased toward familiar actions. This means that greater activity should emerge when observing actions that are familiar, executable, and performed by an agent similar to the perceiver. However, little is known about the neural correlates of action cognition in early ontogeny, nor how form and motion cues might interact when observing familiar vs. unfamiliar actions. In a series of experiments, we have addressed these questions with a population of healthy young adults (using fMRI) and four-month-old infants (using fNIRS). Contrary to current views of sensorimotor brain regions being biased toward familiar actions, we find evidence in both populations that these regions are flexibly engaged by novel motor patterns. Moreover, the data suggest that the brain processes engaged in motion analysis in adults become functionally specialised very early in development.