1. Institute of Archaeology, University College London31–34 Gordon Square, London WC1H 0PY, UK
2. Stone Age Institute1392 West Dittemore Road, Gosport, IN 47433, USA
3. Department of Anthropology and Cognitive Science Program, Indiana UniversityStudent Building 130, 701 East Kirkwood Avenue, Bloomington, IN 47405-7100, USA
4. Functional Imaging Lab, Institute of Neurology, University College London12 Queen Square, London WC1N 3BG, UK