The heritability of life history strategy: The k‐factor, covitality, and personality

Abstract

Archival data from the MIDUS survey (Brim et al., 2000), a nationally representative sample, on 309 MZ and 333 DZ twin pairs aged 25-74 years were used to test the psychometrics and behavioral genetics of life history strategy. We organized 253 of the originally administered 2,000 questions into 30 scales measuring life history traits (e.g., quality of family relationships and altruism towards kin), medical symptoms (e.g., thyroid problems), personality traits (e.g., neuroticism, extraversion, conscientiousness), and social background (e.g., financial security). A single higher-order factor, indicating a general life history strategy, composed of three lower-order factors, was replicated. Factor analyses were then performed on the genetic variance-covariance matrices. We found that (a) a single higher-order factor explained the preponderance of the genetic correlations among the scales and (b) this higher-order factor was itself 68 percent heritable and accounted for 82 percent of the genetic variance among the three component lower-order factors.

A Life-History Model of Human Fitness Indicators

“…Specifically, there was a significant relationship between the K-Factor and F-Factor. However, even this relationship was less robust than previous findings (see Figueredo, et al, 2004). Other results, indicated no relationship between either the KFactor and g-factor, the F-Factor and g-factor, or K-Factor-F-Factor interaction and gfactor.…”

“…However, as with the pilot data, this relationship is weaker than with previous samples (e.g. Figueredo et al, 2004). As an exploration of this finding, the correlation between each pair of factors was calculated separately for males and females.…”

“…For example, fecundity (Rodgers, Hughes, Kohler, Christensen, Doughty, & Rowe, 2001), pubertal timing and menarchal age (Rowe, 2000), and age of first reproduction and menopause (Kirk, Blomberg, Duffy, Heath, Owens, & Martin, 2001), have heritabilities ranging between (.23 -.50). More recently, work examining the K-Factor has reported a factor heritability of .65 (Figueredo, et al, 2004).…”

“…If evolution did shape a subset of individuals to develop the cognitive architecture to focus on long-term reproductive strategies for example, then it should have shaped bodies that are well-prepared to survive long-term (high intelligence, strong immune systems, lower indices of negative health), rather than having a motley assortment of traits that may work in an antagonistic fashion. Indeed, recent research has shown strong positive phenotypic and genetic relationships between the K-Factor, and a global health factor (denoted 'Covitality'; Figueredo et al, 2004;Figueredo, Vásquez, Brumbach, & Schneider, 2007;Figueredo, Vásquez, Brumbach, Sefcek, et al, 2005) Many traits associated with Differential-K theory are heritable in humans. For example, fecundity (Rodgers, Hughes, Kohler, Christensen, Doughty, & Rowe, 2001), pubertal timing and menarchal age (Rowe, 2000), and age of first reproduction and menopause (Kirk, Blomberg, Duffy, Heath, Owens, & Martin, 2001), have heritabilities ranging between (.23 -.50).…”

“…low fecundity, high parental investment, high inter-birth interval, delayed sexual maturity) that produce a few high-quality offspring in a relatively worry-free environment. Due to an evolutionary legacy within these varying environmental niche, traits associated with increased fitness, for that niche) will have become phenotypically and genetically correlated to each other in an overarching, observable, behavioral pattern (Figueredo, Vásquez, Brumbach, & Schneider, 2004).…”