Incest Avoidance as a Function of Environment and Heredity [and Comments and Reply]

Incest Avoidance, the Incest Taboo, and Social Cohesion: Revisiting Westermarck and the Case of the Israeli Kibbutzim

“…Starting in the late 1960s, the hypothesis was revived as a growing body of sociobiologists, evolutionary psychologists, and anthropologists presented an accumulation of research that they claimed unequivocally supported Westermarck's ideas (e.g., Wolf 1966Wolf , 1968Wolf , 1970Shepher 1971Shepher , 1983Bishof 1972Bishof , 1975Alexander 1974Alexander , 1975Parker 1976;Van den Berghe 1980;Bixler 1981). These scholars criticized the Freudian approach for its questionable empirical evidence.…”

Sociobiological Explanations of Incest Avoidance: A Critical Review of Evidential Claims

“…Scholars such as Bischof (1975:37), Bixler (1981b:275), Demarest (1977:323), Parker (1976:285-289), and Shepher (1983:2) propose that human behaviors molded by natural selection are best identified in cultural universals such as the incest taboo. They reason that this taboo (and its underlying genetic mechanisms) resulted because of the deleterious effects produced by close inbreeding; that is, when harmful recessive genes pair in reproductive activities involving persons of common ancestry (Shepher 1983:85-104 [92,1990 den Berghe 1979Berghe :29, 1980van den Berghe and Mesher 1980:300;Bischof 1975;Bixler 1981aBixler , 1981bErickson 1989:267).' In addition, it is asserted that inbreeding leads to homozygosity of the gene pool, which limits the ability of populations to adapt to changing environments (van den Berghe 1983:29).…”

“…In the second case, human sociobiologists have argued that reported cases of incest are exceptional," occurring because of peculiar environmental circumstances that act to obviate the proposed biological mechanisms (van den Berghe 1979Berghe :78, 1980Berghe : 153-1 54, 1983van den Berghe and Mesher 1980;Shepher 1983: 129-130;Bixler 1982Bixler , 1981aBixler , 1981bErickson 1989:284-285). While this assertion may in fact be true, the inclusion of untested and unspecified environmental factors makes it impossible to determine what part of the incest rate is relevant for testing (or falsifying) this sociobiological hypothesis.…”

The incest taboo?

“…Sanderson (2001: 121), for example, specifically asserts that, '[t]he general avoidance of incest among humans, widely considered to be a human universal, is rooted in a biological tendency that exists because of incest's harmful biological consequences'. (Also see recently Bateson, 2005: 25;Pusey, 2005: 61-2; other earlier sources include Bischof, 1975;Bixler, 1981aBixler, , 1981bBixler, , 1981cBixler, , 1982Degler, 1991: 245-69;Erickson, 1989Erickson, , 2005Fox, 1980;Parker, 1976;van den Berghe, 1979van den Berghe, , 1980van den Berghe, , 1983van den Berghe, , 1987van den Berghe and Barash, 1977;van den Berghe and Mesher, 1980).…”