Hybrid Behavior-Genetic Models of the Confounding Gene-Environment Correlations in the Development of Life History Strategy: Two Convergent Approaches
Traditional theories of development and evolutionary developmental psychology propose that early environmental experiences shape an individual’s developmental trajectory. According to the Adaptive Calibration Model (ACM), for example, calibration of speed of life history strategy to ecological cues encountered during development contributes to behavior that is conditionally adaptive to the organism’s environment. These theories emphasize the role of environmental influences and typically do not use designs that control potential genetic confounds. To address this methodological problem, the current study used a genetically informative design to test whether the phenotypic associations of parental instability and abuse with a slow life history factor were confounded by common genetic factors. We analyzed twin and singleton data from the Midlife in the United States (MIDUS) Survey using two convergent structural equation modeling approaches. Both approaches suggest that, when accounting for shared genetic variance across instability, abuse, and slow life history, some hypothesized environmental pathways between the early environmental measures and slow life history were not required. Once genetic factors were controlled, only parental instability was directly related to slow life history, while other hypothesized environmental pathways were non-significant. This suggests that developmental models that emphasize environmental and contextual pathways should control for possible genetic confounds.
Keywords: Parental Instability, Behavioral Development, Early Adversity, Behavioral Genetics, Life History Theory