Enthusiasts contra pessimists

Pervin's target article is an excellent and serious criticism of the current status of the trait concept, especially of one increasingly accepted model of trait structure-the Big Five factors of personality. Pervin applauds the progress being made in trait research but criticizes, for example, that "many trait enthusiasts" have equated "progress in trait theory and research . with a 'consensus' concerning the 'structure' of personality, thereby virtually equating a particular trait model with trait theory and trait theory with the field of personality. " He seems to equate the progress being made with a spectacular breakthrough large enough to explain most of the problems that have bothered personality psychology from its beginning. However, is it not going too far to claim that the five-factor model (FFM) of personality should be able to predict single life criteria, should account for the pattern and organization of individual traits, should specify all the factors that account for stability and change in various aspects of personality functioning, and so forth? Consensus is growing only slowly with regard to the very broadest dimensions of personality description-their structure, stability, and global determinants. But, usually, this consensus quickly disappears and gives way to lively debates as soon as the more specific facets or determinants of personality become the focus of discussion. Contrary to Pervin's assumption, the evidence in support of the heritability of personality seems not to vary "considerably from characteristic to characteristic, being strongest for traits associated with temperament . and weakest for attitudes and beliefs. " Of course, the evidence is strongest for traits if strong means the number of studies that have examined the heritability of traits. However, results from studies conducted by Martin et al. (1986) and Waller, Kojetin, Bouchard, Lykken, and Tellegen (1990) have shown that social attitudes, values, and even religious interests may be genetically influenced to a quite similar extent. In a comparison of genetic and environmental effects on Big Five measures, Loehlin (1992) found the largest heritability for a set of Factor V variables that included two interest scales (see also Bergeman et al., 1993). Accepting the above evidence, it seems unrealistic to assume that belief-type variables are generally more changeable than temperament-type variables. A similar conclusion can be drawn from a comparison of the temporal stability of traits, values, and interests. The stability of general interests (e.g., vocational interests) often exceeds the stability of traits (Strong, 1951; Swanson & Hansen, 1988). Pervin seems to interpret the high stability of individual differences and the importance of genetic factors in the sense that personality change is largely impossible. However, important genetic influences and a high stability of individual differences do not rule out personality development and change. Before searching for relevant factors that cause development and change, it is important to know roughly in which domains most change is taking place. It is one of the strengths of longitudinal genetic studies that they can identify such global domains (e.g., family, adolescence).