Evolutionary theory and reproductive responses to father absence: implications of kin selection and the reproductive returns to mating and parenting effort

Evolutionary theorists are in the business of seeking ultimate explanations for behavior. Ultimate explanations concern why a behavior or trait would have evolved by Darwinian natural or sexual selection and would therefore be adaptive in particular environments. This is in contrast to what is termed proximate explanation, which is usually about more immediate types of motivation, an example being understanding the hormonal underpinnings of a behavior. The topic of father absence due to divorce has not escaped the attention of evolutionary theorists seeking ultimate explanation for its patterns and effects. Many readers may initially pose the question, “Why apply evolutionary theory to father absence?” One answer is that evolutionary theorists were bound to find father absence interesting because reproductive life-history parameters of children from father-absent homes tend to be affected. Variation in life-history parameters, such as age at first reproduction, are known to be major determinants of lifetime reproductive output and of genetic fitness (genetic contribution to future generations). Hence, father absence appears to be associated with the very traits that are the fundamental focus of study for evolutionary research, and due to this, it is likely that researchers working in evolutionary psychology, anthropology, and human biology will continue to try to understand it from an evolutionary perspective.