CHAPTER 6
The Course of Personality
Development inthe Individual
We have used the word stability repeatedly with the assumption that its
meaning is obvious. But in fact stability has several meanings, and a dis-cussion of them is a necessary prologue to a fuller look at the data onpersonality and aging. Different kinds of statistical tests and sometimesdifferent methods of collecting data are necessary when one is lookingfor different types of stability and change. Some kinds of stability arefrankly uninteresting; others form the basis for a whole new way ofthinking about the course of human lives.
Two Different Questions: Stability and Change in Groups
and in Individuals
In Chapter 4 we reviewed at some length the evidence of stability of
mean levels of personality traits. In the simplest case, the cross-sectional study , we found that old people generally scored neither muchhigher nor much lower than young adults on a variety of personalitymeasures. This failure to find marked change in personality contrastswith the evidence of age-related changes in a number of functions. Inchildhood, for example, intelligence, vocabulary , and physical size andstrength obviously increase through adolescence. In later adulthood,
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