1. iCub Facility, Istituto Italiano di Tecnologia, Genoa 16163, Italy
2. Vision Institute, INSERM, University Pierre and Marie Curie, 75252 Paris, France
3. Center for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, 38068, Rovereto, Italy, and Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, G12 8QB, U.K.