The ability to interact with conspecifics is crucial in life, yet there is no consensus on the underlying cognitive and neural mechanisms beyond those associated with imitative behaviors. This project aims to define a coherent model of non-imitative (complementary) motor interactions. The investigators hypothesize that these might be substantially based on the ability to integrate one's own and a partner's action within a unitary, dual- person (dyadic), motor plan that incorporates a shared goal.

With a novel "minimally-joint" paradigm the investigators will test this hypothesis and measure with behavioral measures (i.e., reaction times) whether the supposedly automatic tendency to imitate others is modulated by the need to coordinate with a partner to achieve a shared goal.

This paradigm will be also applied during a functional MRI experiment to describe the underlying neurophysiological patterns; using dynamic causal modeling the investigators will measure how the brain regions relevant for dyadic motor control are functionally linked.

This converging experimental strategy will permit to compare competing psychological and neural models of motor interactions in healthy participants, opening new experimental avenues for studies in adult neuropsychological patients and in children with typical and atypical social development.

Inclusion Criteria:

• right handed; no contraindication to MRI

Exclusion Criteria:

• contraindication to MRI