The areas of the brain that make up the default mode network—the medial temporal lobe, the medial prefrontal cortex, and the posterior cingulate cortex—are turned off when we engage in attention-demanding tasks. But they are very active in autobiographical memory (our personal archive of life experiences); theory of mind (essentially, our ability to imagine what others are thinking and feeling); and—this one’s a doozy—self-referential processing (basically, crafting a coherent sense of self).
