Brains at Work Neuroscience confirms the critical role of the prefrontal cortex in development of theory of mind. Adults and 4- to 6-year-olds were questioned on 40 theory-of-mind examples. The adults answered correctly, as did some 4- to 6-year-olds (passers), though not all (failers). The leftmost images are brain-wave patterns; the other images are fMRI scans—the middle ones represent brain activity when confronted with questions about social interaction (active brains in children and adults) and the rightmost ones show mental activity when distinguishing between reality and belief (needed to pass theory-of-mind questions). Adult brain waves show quick answers, and the contrast (right) shows that they answered quickly with little effort; but the child passers needed to think longer before they answered, and the child failers didn’t give the questions much thought, because they didn’t recognize the problem. The authors concluded that “social cognition and the brain develop together” (Liu et al., 2009, pp. 318, 325).