Misconstruals Miss the Mark

Abstract

El Guindi and Read criticize our (Kushnick and Fessler 2011) exploration of Westermarckian phenomena on the grounds that (1) evidence in support of the Westermarck hypothesis (WH) is weak and (2) our characterization of Karo marriage preferences is misguided. Their critique, however, suffers from a selective use of the literature, a misconstrual of the hypothesis at issue, and factual errors. El Guindi and Read’s first position presumes that human psychology lacks evolved inbreeding-avoidance mechanisms—in their words, “Why should there be a natural aversion among siblings?” While this was a plausible question when Westermarck’s contemporaries challenged him over a century ago, it is an astounding position to adopt today. Voluminous evidence documents such mechanisms in other species (e.g., Pusey 2004), findings paralleled by psychological research in humans independent of the natural experiments that El Guindi and Read problematize (Lieberman et al. 2003, 2007; Fessler and Navarette 2004). Moreover, the evidence regarding natural experiments is far less equivocal than El Guindi and Read suggest. Humans’ detection of biological relatedness relies on a hierarchy of cues (Lieberman et al. 2007). When natural experiments are revisited in light of this (Lieberman 2009; Lieberman and Lobel 2012), the evidence in favor of the WH is substantially strengthened—indeed, contrary to the impression created by El Guindi and Read’s out-of-context quotation, Rantala and Marcinkowska (2011) made exactly this point in their review. El Guindi and Read discuss the prevalence of cousin marriage in Qatar, and point to Henrich and Henrich’s (2007) work among Chaldeans, as evidence of “the desirability of marriage among close kin.” However, the authors are (1) conflating a cultural preference for cousin marriage with the subjective experience of sexual attraction and (2) failing to grasp the role of cosocialization in the WH. There is nothing new in the observation that norms for cousin marriage are common—indeed, it was precisely this that motivated Westermarck’s original work, as the conflict he observed was between a prescription for cousin marriage and a subjective aversion resulting from cosocialization. Correspondingly, al-