Minds at rest? Social cognition as the default mode of cognizing and its putative relationship to the default system of the brain

The default system of the brain has been described as a set of regions which are 'activated' during rest and 'deactivated' during cognitively effortful tasks. To investigate the reliability of task-related deactivations, we performed a meta-analysis across 12 fMRI studies. Our results replicate previous findings by implicating medial frontal and parietal brain regions as part of the default system. However, the cognitive correlates of these deactivations remain unclear. In light of the importance of social cognitive abilities for human beings and their propensity to engage in such activities, we relate our results to findings from neuroimaging studies of social cognition. This demonstrates a remarkable overlap between the brain regions typically involved in social cognitive processes and the default system. We, henceforth, suggest that the physiological 'baseline' of the brain is intimately linked to a psychological 'baseline': human beings have a predisposition for social cognition as the default mode of cognizing which is implemented in the robust pattern of intrinsic brain activity known as the default system. (C) 2008 Elsevier Inc. All rights reserved.