Evidence for the biological basis of incest aversion comes from the studies of children raised in Israeli kibbutzim and of sim-pua marriages in Taiwan (see below).
1. Archives of Sexual Behavior, Vol. 1, No. 4, 1971 Mate Selection Among Second Generation Kibbutz Adolescents and Adults: Incest Avoidance and Negative Imprinting Joseph Shepher Abstract Premarital sexual behavior and marriage patterns were investigated in Israeli kibbutzim. All adolescents and adults of the second generation (N = 65) in one kibbutz were studied. There were no cases of heterosexual activity between any two native adolescents of the same peer group and no cases of marriage between any two members of the same peer group. The avoidance was completely voluntary. Among 2769 marriages contracted by second generation adults in all kibbutzim, there were no cases of intra-peer group marriage. These findings could represent a case of negative imprinting whereby collective peer group education which includes an incessant exposure to peers from the first days of life and an unimpeded tactile relationship among the peers between ages 0-6 results in sexual avoidance and exogamy. 2. *Sexual Attraction and Childhood Association: A Chinese Brief for Edward Westermarck.* Arthur P. Wolf. Stanford University Press, 1995. ISBN: 08047-2426-1 (hardback) �45 Quote from review of this book by Alan Dixson of University of Cambridge: Wolf has made a painstaking and most valuable study of marriage customs among the Chinese. One custom concerned so called "sim-pua" brides; female infants adopted into families and raised side by side with the biological offspring in order to eventually marry a son in the household. Wolf compares the outcome of such sim-pua marriages with those in which girls did not meet their prospective husbands in advance of the wedding day. Sim-pua marriages had a high incidence of adultery, low birth rates and high divorce rates. Thus, marriage to a childhood associate was 2.65 times more likely to end in divorce than an arranged marriage to an unfamiliar partner and 1.24 times more likely to end in divorce than marriages based upon personal choice. Wolf carried out very thorough analyses of over 14000 Chinese women, reaching the conclusion that association during a sensitive period of infancy, spanning approximately the first 30 months, effectively inhibits the development of later sexual attraction. 3. Excerpt from �Consistency and Individual Differences in Facial Attractiveness Judgements: An Evolutionary Perspective�, by Ian Penton-Voak, David I. Perrett Social Research, Spring, 2000 http://www.findarticles.com/cf_0/m2267/1_67/62402556/print.jhtml The clearest example of early experience influencing later sexual behavior in humans is as a mechanism to avoid sibling incest as proposed by Westermarck at the end of the 19th century. From his studies in Morocco, the anthropologist argued that children have an innate tendency to develop a sexual aversion to individuals with whom they live closely in infancy and early childhood, i.e., siblings and parents in the vast majority of human families (Westermarck, 1894). Although his theory was greeted favorably at the time, the leading scholars of the day (including Freud, Durkheim & Malinowski) soon rejected Westermarck's hypothesis (Wolf, 1993), and proposed that a culturally imposed taboo was the major prevention of incest, and one of the defining characteristics of humanity. The "social science orthodoxy" that replaced Westermarck's theory of incest avoidance was built on erroneous assumptions; critically, that incestuous mating is the "natural" choice throughout the animal kingdom (and would be in humans without the intervention of culture), and that incest taboos are universal in humans (van den Berghe, 1983). Incestuous matings are clearly not the norm in non-human animals, and are avoided by various mechanisms such as dispersal or possibly an imprinted aversion to co-socialized peers as sexual partners (Murray & Smith, 1983, see also van den Berghe, 1983, and Bateson's work described briefly above). Excellent discussions of the strengths and weaknesses of Westermarckian and other theories of incest avoidance can be found in Wolf, 1993, and McCabe, 1983. Since the fifties, a series of ethnographic studies have formed "natural experiments" that seem to test, and support, Westermarck's theory. These studies share the common feature that infants and children are placed in intimate contact with other infants in a sibling-like relationship, and yet they are encouraged (or in some cases not prevented) to interact sexually later in life with these co-socialized individuals. The studies most cited in support of Westermarck have taken place in Kibbutzim in Israel (e.g., Shepher, 1971). The methods of child rearing in Kibbutzim provide an ideal test of the Westermarck hypothesis. Firstly, children are socialized from infancy in a mixed sex peer group (a kitah or kevutza), determined by age. They live separately from their parents in the kitah (although parents spend time with their children in the afternoons), in which group solidarity and cooperation between sabras (comrades) is encouraged. Thus, a situation is generated in which the relationship between sabras has much in common with siblings in other cultures (a lengthy period of intimate contact with other individuals during childhood) but also crucial differences (most importantly, the lack of a culturally imposed incest taboo). Westermarck's hypothesis predicts that despite this lack of an incest taboo, the innate predisposition against sexual interaction with co-socialized peers will prevent sabras interacting sexually. Overwhelming evidence appears to support Westermarck: In one detailed study there were no cases of heterosexual activity or marriage between members of the same kitah (Shepher, 1971). Shepher reports that the lack of sexual attraction between peers and the subsequent voluntary avoidance of sexual interaction is actually regretted by those involved. Shepher also summarizes impressive census data in support of Westermarck: Out of 2769 marriages involving individuals raised in kibbutzim "there is not a single case of true intra-peer group marriage to be found" (p. 297). The second commonly reported body of data in support of the Westermarckian thesis is reported in Wolf�s studies of sim-pua marriages in Taiwan (Wolf, 1993). Until the mid-1940s women in much of China and Taiwan gave away their infant daughters, and instead raised other women's daughters as future wives for their sons. The future husband and wife are raised together, sharing sleeping mats in the same fashion as siblings. Westermarck would predict that, at sexual maturity, the husband and wife should have developed an aversion to consummating the marriage due to their intimate childhood association. An excellent natural control group is available to compare the relative success of these forced unions to marriages without co-socialization of partners; the alternative to sim-pua marriage was to marry a mature son to a post-pubescent girl from another family in what was referred to as "major marriage." Such couples had often not met until the marriage ceremony, thus precluding any Westermarckian aversion to sexual activity. Wolf reports that childhood associates are extremely reluctant to consummate their legal bond--the marriage ceremony is itself referred to as "pushing them together". Husbands in sim-pua marriages were three times as likely to visit "dark rooms" (brothels) as men married in the major fashion, an observation that Wolf interpreted as a lack of satisfaction with the sexual aspect of their marriages. Later census studies of more than 14,000 marriages indicate that 2.5 sim-pua marriages end in divorce for every "major" marriage that does so, and the fertility of major marriages is 25% higher than sim-pua marriages (Wolf 1993). The differences in fertility between marriage types are unlikely to be caused by "adoption trauma" or maltreatment of the adoptee. Girls raised for a sim-pua marriage that did not occur (often due to the death of the prospective husband), but instead married other men, had the same fertility and divorce rates in their marriages as women in major marriages. In addition, Wolf ruled out links between socioeconomic status and the low fertility of sim-pua marriages (poorer families tended to prefer such marriages), by considering the taxable value of the husband's estate in his analysis. Wolf also claims to have discovered a "critical period" in which the aversion between the individuals in sim-pua marriages develops. He notes that the age at which the bride moves into the husband's home is crucial; "Brides adopted before age three display sharply reduced fertility and a markedly higher probability of divorce; those adopted after age three do not." (Wolf, 1993). When he reanalyzed the data considering only minor marriages in which the brides moved into the husbands' residences before three years of age, he found that the relative minor/major marriage divorce rate increased to 3:1, and that major marriages were 45% more fertile. The Chinese data complement the findings of the kibbutz studies. Firstly, kibbutz children are never forced to marry peers--the aversion they feel to each other may be depthless, and easily overcome once sex has been made a part of the previously platonic relationship. In the Chinese case the childhood associates are compelled to marry by extremely strong social pressures. Studies of marriage patterns in Israel, Taiwan and elsewhere (e.g., the Lebanon, McCabe, 1983) seems to indicate that childhood association causes later sexual disinterest between peers. Interestingly, theorists seem to propose a "critical" or "sensitive" period of life during which co-socialization must occur to develop these aversive sexual feelings towards certain individuals later in life, analogous to imprinting processes in non-human animals (e.g., Shepher, 1971). Is there, however, a tendency for people to become attracted to individuals similar to those that they are raised with that could be the result of positive imprinting in humans? Other references: Erickson, M. (1989). Incest avoidance and familial bonding. Journal of Anthropological Research, 45, 267-289. This is the earlier of the Erikson articles. In this one he outlines the logic behind his familial bonding theory. He discusses Westermarck's natural aversion theory, animal evidence, the evidence of natural aversion in humans (including a discussion of Sim-pau and Kibbutz), and finally he outlines his familial bonding theory. Erickson, M. T. (1993). Rethinking Oedipus: An evolutionary perspective of incest avoidance. American Journal of Psychiatry, 150, 411-416. In this article Erickson restates the evidence that point to the logic of the familial bonding theory this includes literature from biology, ethology, anthropology, and clinical research. However, he states his predictions that, in light of familial bonding theory, Incest will be: 1) least likely between individual with a secure family bond. 2) somewhat likely to occur between individuals who have a weak or insecure family bond. 3) most likely to occur between individuals with no family bond. He also predicts that incest avoidance should be found when altruistic behavior is present. Allen Esterson Former lecturer, Science Department Southwark College, London [EMAIL PROTECTED] http://www.human-nature.com/esterson/index.html http://www.butterfliesandwheels.com/articleprint.php?num=10 --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
