Personality Development in Emerging Adulthood: Integrating Evidence from Self- and Spouse-Ratings

We examined selfand spouse-ratings in a young adult newlywed sample across a 2-year interval. Rank-order stability correlations were consistently high and did not differ across the two types of ratings. As expected, self-ratings showed significant increases in conscientiousness and agreeableness—and declines in neuroticism/negative affectivity—over time. Spouse-ratings yielded a very different pattern, however, showing significant decreases in conscientiousness, agreeableness, extraversion and openness across the study interval. Spouse-ratings also showed evidence of a “honeymoon effect”, such that they tended to be more positive than self-ratings at Time 1. This effect had dissipated by the second assessment; in fact, the spouse-ratings now tended to be more negative at Time 2. Analyses of individual-level change revealed little convergence between selfand spouse-rated change, using both raw change scores and reliable change index (RCI) scores. Finally, correlational and regression analyses indicated that changes in spouse-ratings were significantly associated with changes in marital satisfaction; in contrast, changes in self-ratings essentially were unrelated to marital satisfaction. These results highlight the value of collecting multimethod data in studies of adult personality development. Personality Development 3 Personality Development in Emerging Adulthood: Integrating Evidence from Selfand Spouse-Ratings Classic models of trait psychology promoted a relatively static view of personality. These traditional models acknowledged that change was prevalent—indeed, even the norm—during childhood and adolescence. Once individuals reached adulthood, however, traits were viewed as essentially being “set in plaster” and highly resistant to change (see Costa & McCrae, 1994; Srivastava, John, Gosling & Potter, 2003; McCrae & Costa, 1990). As evidence has accumulated, however, it has become clear that a simple “plaster” model fails to capture the complexities of personality development across the lifespan. In fact, recent findings establish that personality traits are not static constructs, but rather show meaningful change well into middle age (Caspi, Roberts & Shiner, 2005; Clark & Watson, 1999; Fraley & Roberts, 2004; Roberts, Robins, Trzesniewski & Caspi, 2003; Roberts, Walton & Viechtbauer, 2006). Stability and Change in Adult Personality Rank-Order Stability In reviewing the prior literature on this topic, we will consider three basic types of evidence. The first type of evidence concerns rank-order stability, that is, the extent to which individuals maintain their relative position on the trait continuum over time. In other words, rank-order stability data establish the extent to which individual differences persist over time (e.g., whether a highly conscientious job applicant is likely to remain a highly conscientious employee several years after being hired). The data on this issue are highly consistent and yield several clear conclusions. First, stability correlations for personality traits are moderate to strong in magnitude, even when assessed in childhood and adolescence (Caspi et al., 2005; Roberts & DelVecchio, 2000). Personality Development 4 Second, stability correlations decline in magnitude as the elapsed time interval increases (Caspi et al., 2005; Roberts & DelVecchio, 2000; Watson, 2004). This consistent pattern has helped to establish the existence of true change in personality, given that change is more and more likely to occur with increasing retest intervals (see Watson, 2004). It must be emphasized, however, that stability correlations never approach . 00 and remain at least moderate in magnitude, even across intervals of several decades (Fraley & Roberts, 2004; see also Clark & Watson, 1999; Costa & McCrae, 1992). Third, stability correlations for personality increase systematically with age (Caspi et al., 2005; Clark & Watson, 1999; Roberts & DelVecchio, 2000). Older models of trait development assumed that most personality change occurred prior to the age of 30, after which stability correlations should be uniformly high (for discussions, see McCrae & Costa, 1990; Roberts & DelVecchio, 2000; Srivastava et al., 2003). However, the meta-analytic findings of Roberts and DelVecchio (2000) revealed that stability coefficients for personality continue to increase well into middle age. Fourth, stability estimates do not vary significantly by gender (Costa & McCrae, 1988; Roberts & DelVecchio, 2000; Schuerger, Zarrella & Hotz, 1989). Indeed, in their meta-analytic review, Roberts and DelVecchio obtained identical population estimates of overall trait stability in men and women (see their Table 4). Finally, some trait measures consistently show greater stability than others (Watson, 2004). In this regard, it is important to emphasize that the traits comprising the influential fivefactor model of personality—neuroticism, extraversion, openness, agreeableness, and conscientiousness—all show very similar levels of stability (see Roberts & DelVecchio, 2000, Table 5). In contrast, however, measures of trait affectivity consistently yield lower stability Personality Development 5 correlations (Watson, 2004). For instance, Vaidya, Gray, Haig and Watson (2002) followed a large sample of young adults across an average retest interval of slightly more than 2.5 years. They obtained stability correlations ranging from . 59 to . 72 (mean r = .64) on the Big Five traits, which were assessed using the Big Five Inventory (BFI; John & Srivastava, 1999); in contrast, trait affectivity scales from the Positive and Negative Affect Schedule (PANAS; Watson, Clark & Tellegen, 1988) yielded significantly lower stability correlations of . 51 (Positive Affect) and . 49 (Negative Affect). This pattern of differential stability was replicated in another sample that completed these same measures twice across a two-month interval (Watson, 2004). It is particularly striking that BFI Neuroticism showed significantly greater stability than the PANAS Negative Affect scale in both samples, despite the fact that the two scales assess very similar content and were strongly interrelated. We return to this issue of differential stability later.