How much do our personalities change over time?

According to this study, fundamental personality traits don’t change much from childhood to adulthood:

The continuity of personalityâs association with directly observed behavior is demonstrated across two contexts spanning four decades. During the 1960s, elementary school teachers rated personalities of members of the ethnically diverse Hawaii Personality and Health Cohort. The same individuals were interviewed in a medical clinic more than 40 years later. Trained coders viewed video recordings of a subset of these interviews (N = 144; 68 female, 76 male) and assessed the behavior they observed using the Riverside Behavioral Q-sort Version 3. Children rated by their teachers as âverbally fluentâ (defined as unrestrained talkativeness) showed dominant and socially adept behavior as middle-aged adults. Early âadaptabilityâ was associated with cheerful and intellectually curious behavior, early âimpulsivityâ was associated with later talkativeness and loud speech, and early-rated tendencies to âself-minimizeâ were related to adult expressions of insecurity and humility.

Source: “On the Contextual Independence of Personality: Teachersâ Assessments Predict Directly Observed Behavior After Four Decades” from Social Psychological and Personality Science