Background and objectives: As the mother-offspring relationship is central to human reproduction, the high incidence of postpartum depression symptoms is difficult to explain in evolutionary terms. We proposed that postpartum depression might be the adverse result of evolutionary mother-offspring conflict over maternal investment, and investigated the association between postpartum depression symptoms, infant night waking, maternal sleep disturbance and breastfeeding frequency. Methodology: We conducted a cross-sectional analysis using survey responses at six months postpartum from 1598 Finnish mothers. We hypothesized that infant night waking at six months postpartum would be associated with postpartum depression symptoms, and that this association would be mediated by maternal sleep disturbance and a higher breastfeeding frequency.Results: Infant night waking was associated with postpartum depression symptoms, and this association was mediated by maternal sleep disturbance. Contrary to expectations, we found that the increased breastfeeding was associated with less postpartum depression symptoms. Conclusions and implications: We conclude that postpartum depression symptoms might be the result of increased maternal fatigue stemming from high offspring demands on maternal investment, but that this is not due to the metabolic strain from increased breastfeeding. Studying postpartum depression from the mother-offspring conflict perspective improves our understanding of the involved behavioral processes of both mother and offspring, and thus allows interventions designed to improve the well-being of both parties.
central tenet of nineteenth-century English naturalist Charles Darwin’s theory of evolution is the inheritance of traits from parent to offspring. These shared traits are—at least in part—the result of shared genetic material. To that end, natural selection favors genes that, when in a parent, are associated with optimizing their overall repro- ductive output. By contrast, genes in offspring have been selected to elicit a maximum amount of investment from their caregivers, even if this comes at a cost to the parents’ overall reproductive output. These unequal selective pres- sures result in the evolution of contrasting strategies in parents and their offspring; a phenomenon known as parent-offspring conflict.
Comparisons of children’s perceptions of lesbian mothers to children’s perceptions of heterosexual parents are limited. To investigate whether children’s descriptions of their parents vary by family type (lesbian versus heterosexual) and biological relatedness, we interviewed 29 Finnish children raised by lesbian mothers or heterosexual parents. Parents also completed surveys about division of childcare responsibilities and on six parenting dimensions. We found no systematic differences between the parent types. A clustering of parents based on the descriptions indicated neither family type, parent gender, or biological relatedness systematically explained the variation in children’s descriptions of parents. Implications of our findings are discussed. Contrary to earlier findings, perceptions were similar across parent types, suggesting that perceptions might be shaped primarily by parents’ actual behavior and not by social categories such as gender and relatedness.
Familicides have received relatively little attention and are mostly discussed in studies with broader aims. Here, we reviewed 67 studies from 18 countries on familicides, in which an offender killed or attempted to kill their current or former spouse/intimate partner and one or more of their biological or stepchildren. We conducted a systematic literature search in PubMed, PsycINFO, and Google Scholar. Eight studies investigated familicide specifically, while the remaining reported on familicide cases as a subsample. We retrieved data on offenders’ gender, age, and background, as well as on victims and their relationship to the offender. We also retrieved data on contextual factors and offense characteristics (i.e., modus operandi, offense location, premeditation, and whether or not the offender had committed suicide). We also coded methodological aspects of the studies. Familicides were almost exclusively committed by men and about half of the familicide cases led to the suicide of the offender. Mental health problems, relationship problems, and financial difficulties were prevalent. Because few studies reported population base rates of the investigated characteristics, it is difficult to draw conclusions about specific risk factors. Future research should further investigate typologies of familicide and examine risk factors for different types of familicides.
Good parenting qualities are commonly defined as parental behavior that increases a child’s chances of good health, happiness, and success. Such parental behaviors can include everything from the provision of fundamental resources, such as nutrition and shelter, to modeling good relationship skills and encouraging a healthy lifestyle. Depending on cultural context and values, parental behaviors can also include different forms of education, spiritual guidance, and informing children about expectations and norms that will help them navigate society later in life. Understandably, what is seen as being good parenting is often determined by the effects parental behavior have on the child’s personal development – the evaluation of which is, at least partly, defined by cultural norms and subject to variation over time.
Due to intense selection pressure, humans are thought to have psychological systems that regulate inbreeding. The difference between inbreeding situations where the self is participating and inbreeding among other relatives is only quantitative. Earlier research has not examined whether human inbreeding avoidance follows inclusivefitness theory. Using 27,364 responses from a large population-based sample of 2,353 respondents, we show that humans assess the costs of inbreeding irrespective of their self-involvement. When participants were asked to make forced-choices between different inbreeding situations, the estimated fitness costs explained 85% of the observed choices. The results were similar irrespectively of whether these costs where obtained through one self (i.e., direct inbreeding) or only through close kin (i.e., indirect inbreeding).We conclude that humans perceive also the indirect fitness costs of mating decisions made by close family members.
Introduction Although kin selection, inbreeding avoidance, and cooperation and conflict within the family do not necessitate an ability to identify another individual as a sibling, kin recognition is believed to be a central mechanism in the individual development of kin-directed social behavior in humans (e.g., Penn and Frommen 2004). Concerning siblings, two important kinship cues are co-residence and early maternal perinatal association. The Westermarck Effect Human kin recognition is thought to rest largely on environmental information, and this kin recognition can be direct (e.g., phenotype matching) or indirect. Co-residence and maternal perinatal association are two indirect kinship cues humans use to identify siblings. In 1891, Westermarck hypothesized that two individuals living closely together during childhood will...