John P. Spencer is a Professor of Psychology at the University of Iowa and the founding Co-Director of the Iowa Center for Developmental and Learning Sciences. He received a Sc.B. with Honors from Brown University in 1991 and a Ph.D. in Experimental Psychology from Indiana University in 1998. He is the recipient of the Irving J. Saltzman and the J.R. Kantor Graduate Awards from Indiana University, the Early Research Contributions Award from the Society for Research in Child Development, and the Robert L. Fantz Memorial Award from the American Psychological Foundation. His research examines the development of visuo-spatial cognition, spatial language, working memory, and attention, with an emphasis on dynamical systems and neural network models of cognition and action. He has had continuous funding from the National Institutes of Health and the National Science Foundation since 2001. Michael S. C. Thomas is a Reader in Cognitive Neuropsychology at Birkbeck College, University of London, and the director of the Developmental Neurocognition Lab at the Centre for Brain and Cognitive Development. He is part of a team awarded the Queen's Anniversary Prize for Higher and Further Education in 2006. Dr. Thomas received his B.Sc. in psychology from the University of Exeter, an M.Sc. degree in cognitive science from the University of Birmingham, and a D.Phil. in Experimental Psychology (on behavioral and computational studies of bilingualism) at the University of Oxford, UK. His research focuses on language and cognitive development, and specifically neurocomputational explanations of the variability seen in typical children and in children with developmental disorders. His work combines behavioral methods, computational modeling, and structural and functional brain imaging (see www.psyc.bbk.ac.uk/research/DNL/). James L. McClelland received his Ph.D. in Cognitive Psychology from the University of Pennsylvania in 1975. He served on the faculty of the University of California, San Diego, before moving to Carnegie Mellon in 1984, where he became a University Professor and held the Walter Van Dyke Bingham Chair in Psychology and Cognitive Neuroscience. He was a founding Co-Director of the Center for the Neural Basis of Cognition, a joint project of Carnegie Mellon and the University of Pittsburgh. He served as Co-Director until 2006, when he moved to Stanford University, where he is now Professor of Psychology and is the founding Director of the Center for Mind, Brain and Computation.