• The erections of rapists and nonrapists were measured during audio descriptions of rape and nonrape sexual scenes. On the basis of their erection measures, rapists were separated from nonrapists in that the former developed erections to rape descriptions while the latter did not. The method also discriminated those rapists with the highest frequency of rape, those who had injured their victim, and those who chose children as victims.
Abel GG, Barlow DH, Blanchard EB, Guild D. The Components of Rapists' Sexual Arousal. Arch Gen Psychiatry. 1977;34(8):895-903. doi:10.1001/archpsyc.1977.01770200033002