Childhood adversity, attachment security, and adult relationships: A preliminary study

Several evolutionary theorists have linked early rearing context to later reproductive strategy, hypothesizing that strategies differentiate during development as functional responses to ecological characteristics, by individuals or through parental manipulation. Attachment security has been proposed as a mediator. In this study, 40 young adults were given a multidimensional assessment, including the Hazen and Shaver Adult Attachment Questionnaire. Twenty-four subjects were classified as having secure attachment styles, 16 as nonsecure. The magnitude and predictability of parental investment during childhood was classified as lower if there was a brief intersibling interval, parental divorce, fewer economic resources, or less nurturing parents (i.e., more childhood adversity). Several such indicators were present for 17 people, 12 of whom were nonsecure, compared to only 4 of the 23 others. The nonsecurely attached subjects were less likely to have attained enduring marriages. The 6/16 nonsecure who had a marriage or cohabitation began them at a younger age and after a shorter courtship period than did the 15/24 secure with such relationships. Separations or divorces had already occurred in the relationships of 4/6 nonsecure versus 5/15 secure. Attachment security was associated with childhood adversity and adult relationships for both men and women, when analyzed separately. A retrospective study cannot address cause and effect, because poor adult relationship outcomes might bias recall of parental behavior. However, results are consistent with theories that unpredictable early environments foster short-term rather than long-term mating strategies, possibly through affecting attachment styles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31362/1/0000274.pd

Culture theory: The developing synthesis from biology

We believe that a useful, complete theory of culture is simpler than the dichotomies promoted by the coevolutionary approach suggest. Culture can be regarded as an aspect of the environment into which each human is born and must succeed or fail, developed gradually by the succession of humans who have lived throughout history. We hypothesize that culture results from the inclusive-fitness-maximizing efforts of all humans who have lived. We think the evidence suggests that cultural traits are, in general, vehicles of genic survival, and that the heritability of cultural traits depends on the judgments (conscious and unconscious) of individuals with regard to their effects on the individual's inclusive fitness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44477/1/10745_2005_Article_BF01531192.pd

Contemporary abortion patterns: A life history approach

This paper applies an ecological model of reproductive choice, life history theory, to humans. It models a tension among further investment in self, in present offspring, and later investment in future offspring. Some reproductive decisions for men and women in modern societies may fit this type of "now vs later" analysis; we model the decision of a woman to have an elective abortion. This theory assumes a knowledge of the returns from parental investment (in terms of the child's future mating) and somatic investment (in terms of one's own future mating). Predictions about this decision can be made if the relevant parameters can be estimated: the probability of a child's future reproduction when reared by one or two parents and the probabilities for each of the parents of mating again. We find evidence that abortion decisions are affected by age and previous parity of the mother, and by expectations of available investment by the father or other sources. Still, researchers are left with determining the shape of the trade-off curve between allocations to one's own mating or to a given child's, and with better specifying the effects of variations in resource parameters.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30264/1/0000665.pd

The political psychology of reproductive strategies

We argue that several reproductive strategies that parental investment theory suggests are adaptive for men and for women are in fact most adaptive for individuals able and willing to use power in dominance relationships. We tested whether people's support for social dominance mediates their willingness to use these reproductive strategies. We hypothesized that the strategies of multiple simultaneous mating, resistance to caring for children as one's own, and sexual jealousy will be appealing especially to men who approve of social dominance, and that finding a high-status, high-earning mate will appeal especially to women who approve of social dominance. Support for the hypotheses using multiple samples and multiple measures was found, and theoretical issues are discussed

Sociosexually unrestricted parents have more sons: A further application of the generalized Trivers-Willard hypothesis (gTWH)

Background: The generalized Trivers–Willard hypothesis (gTWH) proposes that parents who possess any heritable trait which increases male reproductive success at a greater rate than female reproductive success in a given environment will have a higher-than-expected offspring sex ratio, and parents who possess any heritable trait which increases the female reproductive success at a greater rate than male reproductive success in a given environment will have a lower-than-expected offspring sex ratio. Aim: One heritable trait which increases the reproductive success of sons much more than that of daughters is unrestricted sociosexual orientation. We therefore predict that parents with unrestricted sociosexual orientation (measured by the number of sexual partners, frequency of sex, and attitudes toward relationship commitment and sexual exclusivity) have a higher-than-expected offspring sex ratio (more sons). Subjects and method: We analyse the US General Social Surveys and the National Longitudinal Study of Adolescent Health (Add Health), both with large nationally representative samples. Results: Our analyses support the prediction from the gTWH. Conclusion: One standard deviation increase in unrestrictedness of sociosexual orientation increases the odds of having a son by 12–19% in the representative American samples