Evolutionary Theory and Child Abuse in Stepfamilies

By far the most utilized theory on child abuse has been evolutionary theory. The so-called “Cinderella effect” (Daly & Wilson, 1998) is that stepparents are more likely to abuse and even kill stepchildren than parents are to harm their biologically related children because of discriminative parental solicitude, a phenomenon that inclines males and females to invest in their own offspring and to “avoid squandering valuable reproductive effort on someone else’s offspring” (Daly & Wilson, 1980, p. 279). Moreover, evolutionary theory also posits that stepchildren are at risk for sexual abuse by their stepparents because the incest taboo does not apply to them.

Although there have been several criticisms of evolutionary theory (e.g., Adler- Baeder, 2006; Giles-Sims, 1997; Mason, 2003), most abuse researchers continue to frame their work from an evolutionary perspective (e.g., Hilton, Harris, & Rice, 2015). For example, when critics have pointed out that most stepparents are not abusive or neglectful of stepchildren (Adler-Baeder, 2006) and that even among nonhuman species, from birds to primates, there are nurturing stepparents (Mason, 2003), evolutionary scholars counter that stepfathers’ and stepmothers’ investments in stepchildren fit with the theory. By being nice to their stepchildren and investing resources in them to ensure their survival, stepparents enhance the likelihood that the parents of their stepchildren will reproduce with them (Anderson, 2000). In short, stepparents’ investments in stepchildren are best understood from an evolutionary perspective as an investment in the children’s biological parent.