Recent efforts to integrate psychometric and neurobiological data about personality have stimulated diverse interdisciplinary applications. The dissociation of major brain systems linked to procedural and propositional memory and learning has clarified the clinical distinction between two components of personality: temperament and character. Temperament can be defined in terms of individual differences in percept-based habits and skills (i.e. related to procedural memory and learning), which are regulated by the amygdala, hypothalamus, striatum, and other parts of the limbic system. In contrast, character can be defined in terms of individual differences in concept-based goals and values (i.e. related to propositional memory and learning), which are encoded by the hippocampal formation and cerebral neocortex. Recent descriptive, developmental, genetic, and neurobehavioral studies indicate that at least four dimensions of temperament and three dimensions of character can be uniquely described and functionally dissociated.