A recent meta-analysis by Roberts, Walton and Viechtbauer published in Psychological Bulletin demonstrate that personality traits change over time. Some things that change over time includes our social interactions, they find, as well as our emotional stability. It would be most interesting to see how these findings relate to our normal sense of self, i.e. our feeling that we are the same person over time.
Here is the abstract:
Patterns of mean-level change in personality traits across the life course: a meta-analysis of longitudinal studies.
Roberts BW, Walton KE, Viechtbauer W in Psychol Bull. 2006 Jan ; 132(1): 1-25
The present study used meta-analytic techniques (number of samples = 92) to determine the patterns of mean-level change in personality traits across the life course. Results showed that people increase in measures of social dominance (a facet of extraversion), conscientiousness, and emotional stability, especially in young adulthood (age 20 to 40). In contrast, people increase on measures of social vitality (a 2nd facet of extraversion) and openness in adolescence but then decrease in both of these domains in old age. Agreeableness changed only in old age. Of the 6 trait categories, 4 demonstrated significant change in middle and old age. Gender and attrition had minimal effects on change, whereas longer studies and studies based on younger cohorts showed greater change. ((c) 2006 APA, all rights reserved).