We characterize Openness/Intellect as motivated cognitive flexibility, or cognitive exploration, and develop a neuropsychological model relating it to dopaminergic function and to the functions of the prefrontal cortex (PFC). Evidence is reviewed for sources of Openness/ Intellect shared with Extraversion and sources unique to Openness/Intellect. The hypothesis that the cognitive functions of the dorsolateral PFC are among the latter was tested using standard measures of cognitive ability and a battery of tasks associated with dorsolateral PFC function (N = 175). Dorsolateral PFC function, as well as both fluid and crystallized cognitive ability, was positively related to Openness/Intellect but no other personality trait. Additionally, facet level analysis supported the characterization of Openness/Intellect as a primarily cognitive trait.