  There is a significant feminist response to this research (see especially Travis 2003 edited volume). For example, Elisabeth Lloyd (2003) reveals gaps and unjustified assumptions in Thornhill and Palmer's evolutionary arguments. She points out that Thornhill and Palmer's view is problematically adaptationist, meaning that it exhibits an unjustified commitment to natural selection over other kinds of explanation (see Gould and Lewontin 1979 for the main explanation of, and argument against, adaptationism (see the entry on adaptationism), Further, Lloyd shows that they fail to demonstrate that the behavior in question is heritable or that it is the product of natural selection. Finally, Lloyd points out that Thornhill and Palmer make the unjustified assumption that rape is a unitary phenomenon in the face of the “striking disunity among the various acts that are classed as rape” (240).