The neuroscience of social interaction

The increasing refinement of fMRI has given neuroscientists insights into how the living cortex participates in a host of human scenarios. This approach has had a dramatic impact on the study of social interactions. Suddenly fields as diverse as robotics, primate behaviour, neuroanatomy, neurophysiology and child psychology have a dynamic relationship to socially crippling conditions such as autism. New information has emerged about segregation of function, even at the level of the cognitive and perceptual machinery that serves human interactions. In crafting the theories and challenges that enrich what must surely be one of the greatest mysteries of the human condition, it is difficult to imagine a better mix of articles than those in this collection. The book has three sections. In the first, Biological motion: decoding social signals, Puce and Perrett present an excellent review of the historical origins of, and cortical participation in, the representation of biological motion, revealing the manner in which the movement of living things penetrates specific aspects of human consciousness there to play a fundamental role in the creation of social strategies. The utilization of this information is taken up in the next article by Csibra, who argues that human infants inherently respond to the goals apparent in the movements of animated shapes, the ‘body language’ of living agents, in a manner that does not necessarily implicate cognitive processes. The Friths then present an insightful review of the involvement of thought in the social interactions of humans as young as 18 months, comprehensively reviewing recent fMRI studies on a host of psychosocial scenarios. These implicate several post-prefrontal areas in the representation of emotion and body language, also the medial prefrontal cortex (Brodmann’s area 9) in social cognition. Their article provides a provocative introduction to that of Rittscher et al., which reports attempts to design machines able to read body language, a problem which is primarily visual but also requiring the utilization of ‘motion primitives’ as a means of quantitatively representing and interpreting the nuances of human behaviour. In the second section, Mirror neurons: imitating the behavior of others, Meltzoff and Decety present their classical work on imitation in postnatal infants and describe their more recent attempts to use machines to test whether, in imitating complex actions, older infants focus on the goals, or the means of achieving them, or the identity of the agent. At the end of their article they cite the fascinating theory that the inferior parietal cortex may be unique to humans and apes, thus accounting for the oft-mentioned inability of monkeys to imitate. Wohlschlager et al. then discuss their theory of goal-directed imitation wherein Book Reviews