Personality Development: Intentional Strategy or Automatic Adaptation?
Personality development, like many aspects of phenotypic development seen across species, can be viewed within the framework of flexible ontogeny (Hagen & Hammerstein, 2005). An individual’s behavioral patterns across time represent that individual’s context-dependent adaptive strategy for coping with the unique environmental challenges he or she faces. Development and expression of a given strategy involves a complex interplay between latent genetic dispositions and conditional learning; individuals can have evolved the capacity to implement a given strategy (i.e., encoded in their genes) and can flexibly employ this strategy only when inhabiting an environment in which the strategy will lead to adaptive outcomes (i.e., conditional learning). Indeed, personality theorists have increasingly begun to view traits as context-dependent reaction norms which are implemented through similar interactions between genetic predispositions and environmental triggers (Penke, Denissen, & Miller, 2007), and emerging evidence suggests that variation in state personality (i.e., a momentary instance of trait-relevant behavior) is explained in part by extant situational pressures (Fleeson, 2007).
The concept of conditional learning raises the issue of whether adaptive strategies are consciously implemented or whether they automatically arise due to environmental pressures to promote an individual’s survival. Consider the recent finding that individuals who enter military service after high school show relatively little increases in agreeableness over the subsequent six years compared to individuals who enter community service (Jackson, Thoemess, Jonkmann, Lüdtke, & Trautwein, 2012). Stated differently, high school graduates generally increase in agreeableness in the six years following high school, but those who enter the military do not show this developmental trend. The flexible ontogeny framework suggests that, whereas all individuals have the latent capacity to act in an agreeable manner as they enter young adulthood, environmental pressures of military service (e.g., the need to show callousness toward enemies in combat) curb this capacity and cause individuals to adopt a less agreeable strategy. Again, however, we do not know whether these individuals a) consciously chose to act less agreeable given the knowledge that such behavior would increase their likelihood of survival; or b) less agreeable behavior merely emerged due to day-to-day situational pressures inherent in the military. While consideration of these two possibilities risks rekindling the debate on whether behavior is more attributable to persons or situations, a better understanding of the mechanisms driving flexible ontogeny would help elucidate the how and why of personality development.