1. RIKEN Center for Brain Science TOYOTA Collaboration Center, Nagoya, Japan
2. School of Electronic Engineering and Computer Science, Queen Mary University of London, London, UK
3. Computer Science and Artificial Intelligence, University of Milano Biccoca, Milano, Italy
4. Graduate School of Engineering Science, Osaka University, Osaka, Japan
5. Cognitive Architecture for Collaborative Technologies Unit, Italian Institute of Technology, Genova, Italy
6. Department of Language and Information Sciences, University of Tokyo, Tokyo, Japan
7. Department of Human and Computer Intelligence, Ritsumeikan University, Shiga, Japan