Can Evolutionary Principles Explain Patterns of Family

Can Evolutionary Principles
Explain Patterns of Family
Archer, J. (2013). Can evolutionary principles explain
patterns of family violence?. Psychological Bulletin, 139(2),
403-440. doi:10.1037/a0029114
• “Violence within families is an extensive field of study whose
research has wide-ranging implications for social policy”
• Focus on violence, subset of aggression
• Application of evolutionary principles to research on family
• Kin Selection – Adaptive for animals to distinguish kin from non kin
Evolutionary Principles &
Family Violence
• Degree of shared kinship and Reproductive Value (RV)
• Age, resources, and offspring quality
• Resource Holding Power (RHP)
• Characteristics of individuals engaged in conflicts
Kin Selection
• Kin are more likely than unrelated individuals to cooperate
and less likely to compete, since altruistic behavior provides a
way of perpetuating shared genes (W.D. Hamilton)
• Inclusive Fitness
• Parents care for offspring because they share genes that are rare in
• Hamilton’s Rule
• Evolutionary costs and benefits
• Benefits of helping a relative X coefficient of relatedness = costs
• High rates of violence among step families
• Kin Recognition
• Animals must learn to differentiate kin
• Assessment of the degree of resemblance
• Facial resemblance = more cooperation and greater attraction
Reproductive Value (RV)
• RV is a measure of how likely individuals are to contribute to
future generations
• Offspring are more important to parents as a means of perpetuating
genes than parents are to offspring
• As offspring grow older, they become more valuable to parents
• As parents grow older, their RV drops
• Rates of violence
• Offspring most at risk early in life, parents at risk the older they come
Attachment & Selective
• Focus on offspring’s bond with his/her primary caretaker
• Family violence
• Attachment bond acts as an inhibitory influence on the
motivational system underlying aggression
Resource Holding Power
• Game theory model of the evolution of animal fighting
(Parker, 1974)
• Evaluating potential opponents fighting ability and act on
information – fight or flee
• Fighting ability = RHP
• Assessing RHP and acting accordingly are an evolutionarily stable
strategy (ESS; Maynard Smith, 1982)
• RHP throughout the lifespan
• Father son reversal of RHP
Violence Between Parents,
Offspring, and Siblings
• Parental violence to unrelated Children
• Reconstituted families are “crucibles for conflict” (Emlen, 1997)
• Inclusive fitness
• Degree of genetic relatedness
• Higher rates of physical violence to children with stepparent
across cultures
• Higher risks from stepparents for homicide (Daly and Wilon, 1988)
• Hostile rather than instrumental killings
• Beating vs. suffocation, drowning, strangling, shooting, followed by suicide
Violence between Parents,
Offspring, and Siblings Cont.
• Parental violence to genetic children
• Parent offspring conflict model (Trivers, 1974)
• Conflict will arise from offspring seeking more resources from parent
• RVp
• Reproductive value of parent decreases so parents value children
• Decline in parent abuse as parent grows older
• RVc
• Reproductive value of child is low early in life, but grows
• Risk of abuse and neglect by parents higher for offspring’s early
years, and then declines
• Paternity Uncertainty
• Facial resemblance
Violence Between Parents,
Offspring, and Siblings Cont.
• Offspring’s Violence to Parents
• As parents RV declines, offspring’s RV rises
• Parents contribution to offspring’s fitness decreases
• Parents RHP decreases as offspring’s RHP increases
• Aggression to parents is frequent at
young ages, but declines
• Children express themselves
physically, but learn to inhibit
• Increase in offspring to parent
homicide in 20’s
• Increase in offspring RHP
• More violence to stepfathers
Violence Between Parents,
Offspring, and Siblings Cont.
• Violence Between Siblings
• Inclusive Fitness
• Predicts that genetic siblings will have less conflict than unrelated
• Confirmed in one study, more research is needed
• Physical aggression is frequent between siblings, but generally at
low levels
• At young ages when aggression was common, older siblings
showed more of it
• Homicide most often occurs later in life between siblings
• Greater tendency for siblings to cooperate and kill unrelated people
Violence Between Partners
• Partner violence as mate guarding
• Paternity Uncertainty
• Male doesn’t want to raise child that is not potentially his
• Built in behavioral measures to maximize paternity certainty
• Absence of sex difference in physical aggression to partners
• Greater male – female violence found only in low gender
empowerment nations
• Findings support broader view – both sexes show mate guarding
• Men want to avoid raising an unrelated child, women don’t want to lose a
Summary & Conclusions
• Kin Selection
• Greater risk of violence toward stepchildren than genetic children
• Some parents showed abuse to stepchildren and not their genetic
• Weaker affective bonds with stepchildren
• Reproductive Value (RV)
• Violence by parents highest in infancy and decline through
• Supported for both violence and homicide
• Supported by cues to poor physical prospects for child and shortage
of resources
• Decline in parental RV with age
• Risk of violence to offspring declines
• Risk of violence from offspring increases
Summary and Conclusions
• Resource Holding Power (RHP)
• Older siblings generally initiate more physical aggression than
younger ones
• Boys moreso than girls
• Sibling with lower RHP seeks help from parents
• Reversal in parent-offspring violence in teenage years for boys
• Partially supported
• Increase in lethal violence in 20’s in case of sons to fathers
• What are your thoughts on the research?

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