1. Diagnostic testing confirms this relationship, finding intelligence and academic achievement to be intercorrelated within persons, so much so that weak intelligence-achievement correlations contribute toward the diagnosis of specific learning disorders.
- 2. The two forms of altruism discussed represent major additions to modern Darwinian Theory in that they explain the existence of altruism, which, from an evolutionary perspective, might at first seem paradoxical. W. D. Hamilton developed the concept of inclusive fitness, an instance of kin selection, showing that promoting the fitness of one’s relatives indirectly raises the proportions of one’s own genes within the population (Hamilton 1964; Campbell 1972; Williams 2008). Robert R. Trivers developed the concept of reciprocal altruism, explaining the fitness benefits derived from mutual aid where help at one time is repaid in kind at another (Trivers 1971, 2005).
- 3. Conscientiousness, along with Openness, Extraversion, Neuroticism, and Agreeableness, is part of the five factor model of personality derived from the factor analysis of adjectives used to describe human personality.
- 4. Each of the five factor traits described in the previous note are routinely divided into six facets by theory and on assessments of personality such as the NEO-PI-R and the NEO-FFI. Facets are very similar to factors in that their goal is to divide a larger construct into its component parts. Nevertheless, the factors discussed in the body of the text are derived from factor analysis derived from factor analytic studies.
- 5. Murray quotes James Wilson, who in turn quotes Cicero, on the foundational importance of marriage to all the higher-order social institutions that rest upon it. Tocqueville is further quoted, to demonstrate the propensity of early American women to defer marital bonds and to contract marriage with informed decision and selective discrimination. The freedom of choice exercised by women, which Tocqueville describes and admires as the superiority of American women, is nothing other than female choice, one of two forms of sexual selection driving male behavior. Studies of sexual selection and life history evolution suggest that ecology drives female choice, which in turn drives male evolution, with resultant effects on the mean life history of a population.