Expressive handovers: neural and behavioral effects of different attitudes in humanoid actions

Interacting with others requires the ability to evaluate their attitudes based on how actions are performed. Even a simple everyday act as handing over an object acquires a different meaning if it is performed gently or harshly. This little difference can impact the whole evolution of a collaboration, as people tend to react aggressively to aggressive behaviors. Concerning human-robot interaction, it is important to be aware of the impact that robot motion features might have in the partner’s interpretation of their actions. The challenge we address in this research is to endow the iCub humanoid robot with the capacity to communicate intuitively positive and negative attitudes in its own actions. The results of a series of fMRI and interactive studies showed that robotic passing actions performed with kind and aggressive attitudes (or vitality forms) have a significant impact not only on how the brain processes the observed robotic action, but also on the way the human partners act in response to it.