Human beings use facial expressions not only to express their own current feelings, but also to engage with the feelings of others. From very early age on people have a tendency to sometimes mimic others’ expressions, for example when a baby returns the smile of their parents. Many psychologists believe that such facial mimicry might make it easier for people to communicate our openness to engage and empathise with others. In the past it has been assumed that humans are born with a reflex-like tendency to imitate any expression they see independent of its meaning. But it might also be possible that children’s facial responses are already a sign of their ability to interpret the relevance of the expressions they see. Since appropriately engaging with others nonverbal behaviour is crucial for everyday social life, we want to find out more about the development of these fundamental processes.