Personality and temperament
This chapter will summarize work relating to the inheritance of personality and temperament. As with the heredity of intelligence, evidence in this area has been accumulating for a long time and covers an astonishingly wide range of personality dimensions. Before examining this material we shall discuss briefly the various meanings of personality and temperament. Many of the problems which we shall consider have already been encountered in the chapter on intelligence.
Theories of personality have a long history ( McClelland, 1951). All through the ages man has asked the question "What am I?" But it was not until the nineteenth century that the problem was attacked in an empirical manner. Freud and his followers were among the first to open up the field of inquiry, though it should be emphasized that Galton played an important role. Since this early work, a great deal has been written on the subject, more, in fact, than can be summarized here. A number of excellent source books are available that discuss thoroughly the various approaches that have been taken over the last fifty years ( Allport, 1937; Cattell, 1946; Eysenck, 1947; Murphy, 1947; Brand, 1954; Hall and Lindzey, 1957). It is pertinent, however, to establish an orientation in this chapter by considering briefly the dimensions with which we shall deal. Personality tests range from verbal responses to Rorschach inkblots to finger-tapping rates. Any reaction may be looked upon as reflecting some aspect of personality and temperament, insofar as it relates to the emotional responsiveness of an individual. By "emotional" we refer not only to violent changes or disturbances in behavior, but also to the relatively mild states involved in dislikes or likes of particular objects or events. The words given by a subject in free-association experiments, the responses made to a Thematic Apperception Test card, or the way a question-