Individual Differences in Temperament: Definition, Measurement, and Outcomes☆

The concept of temperament presumes a level of behavioral and emotional continuity that appears early in postnatal life and persists across the lifespan. Understanding the basis for individual differences in temperament has long been a focus of human inquiry. Initially, modern researchers relied on person-centered, psychological concepts and physiological measures to explain temperamental differences consistent with their theories. However, temperament is known to interact with the effects of environmental factors on development. In studies of neuroscience and genetics, investigators now examine the complex interplay between constitutional factors underlying temperament and environmental contingencies. This approach has shifted the field from descriptive accounts of temperament toward an understanding of its causal underpinnings.