Comments on the original article "Patterns of Mean-Level Change in Personality Traits Across the Life Course: A Meta-Analysis of Longitudinal Studies," by B. W. Roberts, K. W. Walton, and W. Viechtbauer. Although Roberts et al depicted the present authors as proponents of the immutability of traits, in fact we have always acknowledged the possibility of change, and we are pleased that the results of their meta-analysis are consistent with our conclusions about modest change after age 30. We agree with B.W. Roberts et al that analyses should be conducted at the level of more specific traits, but prefer the 30 facets of the Revised NEO Personality Inventory to the Social Dominance-Social Vitality distinction. The origins of age changes might be found either in environmental influences common to all cultures or in biologically based intrinsic maturation; we offer some reasons for preferring the latter interpretation. Meta-analyses are useful but not definitive, and the resolution of the origin question lies in further research.