Changing Minds, Changing Brains

Measures of brain function are used today in many areas of psychological research, and developmental psychology is no exception. The infusion of cognitive neuroscience into psychology has been met variably with enthusiasm, skepticism, and opposition. The most productive attitude towards this sea change, I maintain, consists of a healthy dose of both enthusiasm and skepticism [see also Kagan, 2006]. The business of a developmental psychologist is to understand age-related changes in cognition, but measures of overt behavior alone do not provide a complete account of mental processes. Below, I discuss four ways in which neuroscientific methods, like noninvasive brain-imaging techniques, can complement behavioral techniques in the study of the developing mind [for a summary of these and other neuroscientific techniques, see Bunge & Kahn, 2008]. First, neuroscientific methods can provide a deeper mechanistic understanding of developmental changes in behavior. Do we perform a particular task better as adults than as children because of increased efficiency of one or more cognitive processes? If so, children and adults should recruit the same brain network while performing this task, but adults should engage it less strongly. Or, do we perform the task better as adults because an additional, or different, cognitive process is involved? If so, adults should engage additional or distinct brain regions with respect to children. Second, even in the absence of substantial behavioral changes, neuroscientific methods can uncover informative changes in brain function. On the basis of the unexpected finding that children engaged the left frontal lobe whereas adults involved the right frontal lobe while performing a cognitive task, we hypothesized that children adopted a verbal strategy, whereas adults adopted a visuospatial strategy. We subsequently obtained behavioral evidence for this brain-based prediction. Another example of changes in brain function without large changes in behavior comes from the aging literature. Older adults exhibit bilateral frontal activation on tasks for which younger adults recruit only the left or right frontal cortex [Bunge et al., 2002]. Thus, older adults achieve similar levels of performance to younger adults by recruiting additional brain regions.