Introversion is a construct within personality psychology characterizing a fundamental dimension of individual differences in psychological orientation and energy focus. It investigates the degree to which an individual's attention and energy are directed inward towards subjective experiences, thoughts, and feelings, as opposed to outward towards external stimuli and social interaction. Key characteristics include a preference for solitude or small group interactions, introspection, and a tendency to feel drained by extensive social engagement or high levels of external stimulation, signifying its importance in explaining variability in social behavior, environmental preferences, and cognitive processing styles within personality research and differential psychology.