1. UCL Institute of Cognitive Neuroscience, University College London, Alexandra House, London WC1N 3AR, UK
2. Interacting Minds Project, Institute of Anthropology, Archaeology, Linguistics, Aarhus University, and Centre of Functionally Integrative Neuroscience, Aarhus University Hospital, 8000 Aarhus C, Denmark
3. Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK
4. Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, UK