Copying the behaviour of others is important for forming social bonds with other people and for learning about the world. After seeing an actor demonstrate actions on a novel object, typically developing (TD) children faithfully copy both necessary and visibly unnecessary actions. This ‘overimitation’ is commonly described in terms of learning about the object, but may also reflect a social process such as the child’s motivation to affiliate with the demonstrator or to conform to perceived norms. Previous studies of overimitation do not separate object learning and social imitation because they use novel objects. Even though researchers consider these objects to be causally transparent in their mechanism, young children’s causal reasoning about novel objects is unclear. The present study measures the social component of overimitation by using familiar objects, which preclude the learning component of the task. Here we report a significant reduction in overimitation in children with autism spectrum conditions (ASC). This is coherent with reports that these children have profound difficulties with social engagement and do not spontaneously imitate action style (see also).