Westermarck effect: lack of desire towards childhood friends

Many people are interested in knowing what characteristics and behavior styles enhance attractiveness. personal, but there are fewer who also try to find out about the factors that kill at the root any possibility of attraction.

That is why it is not surprising that so little is known about the Westermarck effect, a hypothetical psychological phenomenon according to which human beings are predisposed not to feel sexual desire towards women people with whom we associate continuously during our early childhood, regardless of whether they are relatives or not.

Why might this curious trend occur? The explanation proposals that many researchers consider to solve the unknown of the Westermarck effect have to do with the phenomenon of incest.

Incest, universal taboo

In all modern societies there are taboos, that is to say, behaviors and ideas that are not socially accepted for reasons that have to do, at least in part, with the prevailing morality or the religious beliefs associated with that culture. Some of these taboos, such as intentional homicide or cannibalism, are easy to find inconvenient from a personal point of view. pragmatic, because if they become generalized, they could destabilize the social order and cause an escalation of violence, among other things things.

However, there is a universal taboo that we can find in practically all cultures throughout history but whose prohibition is difficult to rationally justify: incest.

Taking this into account, many researchers have wondered what is the origin of the omnipresent rejection generated by everything related to relationships between family members. Among all the hypotheses, there is one that has gained strength in recent decades and is based on a psychological effect based on the combination of genetic innateness and behaviors learned. This is the hypothesis of the Westermarck effect.

matter of probability

Edvard Alexander Westermarck he was a Finnish anthropologist born in the mid-19th century known for his theories on marriage, exogamy, and incest. Regarding the latter, Westermarck he proposed the idea that incest avoidance is the product of natural selection. For him, avoiding reproduction among relatives would be part of an adaptive mechanism that we carry in the genes and that would have spread through the population due to the advantageousness of this behavior in terms of evolutionary.

As the offspring resulting from incest can have serious health problems, the selection would have carved in our genetics a mechanism for us to feel aversion to it, which would in itself be an advantage adaptive.

Ultimately, Westermarck believed that natural selection has shaped the sexual tendencies of our entire species by preventing close family relationships.

Suppressing sexual attraction to avoid incest

But how would natural selection promote incest avoidance behaviors? After all, there is no feature by which we can recognize brothers and sisters with the naked eye. According to Westermarck, evolution has decided to use statistics to create a mechanism of aversion between relatives. Since people who see each other on a daily basis during the first years of life and belong to the same environment have many possibilities of being related, the criterion used to suppress sexual attraction is the existence or not of proximity during childhood.

This predisposition to not feel attraction for the people with whom we come into contact periodically during the first moments of our life would be of genetic bases and would suppose a evolutionary advantage; but, as a consequence of this, nor would we have sexual interest in old childhood friendships.

the anti-oedipus

To better understand the mechanism through which the Westermarck effect is articulated, it is useful to compare this hypothesis with the ideas about incest proposed by Sigmund Freud.

Freud identified the incest taboo as a social mechanism to repress sexual desire towards close relatives and thus make possible the "normal" functioning of society. He Oedipus complex would be, according to him, the way in which the subconscious fits this blow directed against the sexual inclinations of the individual, from which it follows that the only thing that makes the practice of incest something general is the existence of the taboo and the punishments associated with it.

The biologist's conception of the Westermarck effect, however, directly violates what is proposed in the Oedipus complex, since in his explanation of the facts the taboo is not the cause of sexual rejection, but the consequence. This is what makes some evolutionary psychologists hold the idea that it is evolution, more than culture, the one that speaks through our mouths when we express our opinion about the incest.

Some studies on the Westermarck effect

The Westermarck effect proposal is very old and has been buried by a barrage of criticism from anthropologists and psychologists who defend the important role of learned behaviors and cultural dynamics in the sexuality. However, little by little she has been raising her head to accumulate enough evidence in her favor.

When talking about the evidence that reinforces Westermarck's hypothesis, the first case that is mentioned is usually that of J. Sheper and her study of resident populations in kibbutz (communes based on the socialist tradition) of Israel, in which many unrelated girls and boys are raised together. Despite the fact that the contacts between these children are constant and last until they reach adulthood, Sheper concluded that the occasions in which these people get to have sexual relations are rare at some point in her life, making it much more likely that they will end up marrying others.

Other interesting examples

Since Sheper's article was published reviews have been made on the methodology used to measure sexual attraction without cultural or sociological factors interfering and, however, many other studies have also been published that reinforce the hypothesis of the effect Westermarck.

For example, an investigation based on questionnaires passed to the Moroccan population showed that the fact of having close and continuous contact with someone during the early childhood (regardless of whether she is related or not) makes it much more likely that as an adult he will dislike the idea of ​​marrying this person.

Lack of attraction present even in 'Westermarck marriages'

In addition, in cases where two people who have been raised together without sharing blood ties marry (for example, by adult imposition), tend not to leave offspring perhaps due to lack of attraction. This has been found in Taiwan, where traditionally there has been a custom among some families of letting the bride grow up in the house of the future husband (marriage Shim-pua).

The taboo is linked to continued coexistence

Evolutionary psychologist Debra Lieberman also helped bolster the Westermarck effect hypothesis through a study in which she asked a number of people to fill out a questionnaire. This file contained questions about her family, and also presented a series of reprehensible actions such as drug use or homicide. The volunteers had to order according to the degree with which they seemed wrong, from more to less morally reprehensible, so that they would be placed in a kind of ranking.

In the analysis of the data obtained, Lieberman found that the amount of time spent with a brother or sister during childhood was positively correlated with the degree to which incest was condemned. In fact, one could predict the extent to which a person would condemn incest just by looking at the degree of exposure to a sibling in childhood. Neither the attitude of the parents nor their degree of kinship with the brother or sister (were taken into account also adoptions) significantly affected the intensity of the rejection towards this practice.

many doubts to solve

We still know very little about the Westermarck effect. It is unknown, first of all, if it is a propensity that exists in all the societies of the planet, and if it is based or not on the existence of a partially genetic trait. Of course, nor is it known which genes might be involved in its functioningeither, and if it manifests itself differently in men and women.

The answers about the psychological and universal propensities typical of our species, as always, are waiting. Only decades of continuous research can bring to light these innate predispositions, buried in our bodies under thousands of years of adaptation to the environment.

Bibliographic references:

• Bergelson, V. (2013). Vice is Nice But Incest is Best: The Problem of a Moral Taboo. Criminal Law and Philosophy, 7(1), pp. 43 - 59.

• Bittles, A. h. (1983). The intensity of human breeding depression. Behavioral and Brain Sciences, 6(1), pp. 103 - 104.

• Bratt, C. S. (1984). Incest Statutes and the Fundamental Right of Marriage: Is Oedipus Free to Marry?. Family Law Quarterly, 18, p. 257 - 309.

• Lieberman, D., Tooby, J. and Cosmides, L. (2003). Does morality have a biological basis? An empirical test of the factors governing moral sentiments relating to incest. Proceedings of the Royal Society of London: Biological Sciences, 270(1517), pp. 819 - 826.

• Shepherd, J. (1971). Mate selection among second generation kibbutz adolescents and adults: incest avoidance and negative imprinting. Archives of Sexual Behavior, 1, pp. 293 - 307.

• Spiro, m. AND. (1958). Children of the Kibbutz. Cambridge: Harvard University Press. Cited in Antfolk, J., Karlsson, Bäckström, M. and Santtila, P. (2012). Disgust elicited by third-party incest: the roles of biological relatedness, co-residence, and family relationship. Evolution and Human Behavior, 33(3), pp. 217 - 223.

• Talmon, Y. (1964). Mate selection on collective settlements. American Sociological Review, 29(4), pp. 491 - 508.

• Walter, a. (1997). The evolutionary psychology of mate selection in Morocco. Human Nature, 8(2), p. 113 - 137.

• Westermarck, E. (1891). The history of human marriage. London: Macmillan. Cited in Antfolk, J., Karlsson, Bäckström, M. and Santtila, P. (2012). Disgust elicited by third-party incest: the roles of biological relatedness, co-residence, and family relationship. Evolution and Human Behavior, 33(3), pp. 217 - 223.

• Wolf, A. (1970). Childhood Association and Sexual Attraction: A Further Test of the Westermarck Hypothesis. American Anthropologist, 72(3), pp. 503 -515.