Stability

One issue of interest to temperament researchers has been the extent of stability in various temperament dimensions. Many studies have delineated patterns of continuity and discontinuity in trait measures of emotionality (Hagekull, 1989; Huttunen & Nyman, 1982). These studies suggest that instability is as much a part of development as stability is. There is evidence from personality development literature both in adulthood and childhood (Tellegen, 1988) which suggests that stability in any given individual difference dimension may also be construed as a meta-characteristic that cuts across content dimensions of social behavior. Thus, there are some individuals who appear to be stable in a number of personality characteristics, while there are others who appear to show fluctuations or discontinuities in a number of personality characteristics.

Persistence in the expression of “inappropriate behaviors,” construed in very general terms, is likely to be associated with continued risk for pathology. For example, persistence in aggressive behavior throughout childhood is associated with externalizing tendencies (Cole & Zahn-Waxier, 1994). Thus, our ability to model stability or change in traits over time would also increase our ability to predict and differentiate the dynamics in risk status. Such use of the concept of stability in trait measures has been examined in adult personality studies. Tellegen (1988) has suggested a regression-based approach to quantifying consistency in personality assessments in adult populations. This approach involves partialling the mean and the variability of an individual's score on a given trait measure, collected at multiple time points. Examining the interaction of these main effects (i.e., the mean and variability) is one way in which we can capture both change and stability as a meta-dimension.

The use of such approaches with measures of temperamental characteristics of at-risk children can allow us to capture such a meta-dimension in various

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emotional reactions. Examining stability and change would also help explain why some children's anger propensities in toddlerhood, for example, predict a later increase in externalizing tendencies for some individuals but not for others. In other words, stability as a meta-dimension on individual differences in emotionality may help show how context-inappropriate expressions of certain emotions can evolve into behaviors that meet diagnostic criteria for a variety of disorders. Similarly, instability in measures of emotionality may account for our decreased ability to predict the externalizing and/or internalizing tendencies of some children (Zahn-Waxler et al., 1990).