Friday, 10 September 2010

Freud was right: we are attracted to our relatives

Freud said there'd be no need for incest to be such a powerful cultural taboo if people weren't sexually attracted to their relatives in the first place. Given that in-breeding is associated with increased mortality, he argued that the incest taboo had emerged as way to keep our dangerous incestuous desires in check. Evolutionary psychologists take a strikingly different view. Inspired by Edward Westermarck, the Finnish sociologist and anthropologist, they argue that we've evolved automatic psychological processes that lead us to find our relatives sexually aversive, not attractive, thus decreasing the likelihood of in-breeding occurring. Who's right - Freud or Westermarck?

Chris Fraley and Michael Marks asked 74 students to rate the sexual attractiveness of 100 strangers' faces. Crucially, for half the students, each face was preceded by a subliminal presentation of a family member. For the remaining control students, the subliminal presentation was of someone else's family member, i.e. a non-relative.

Westmarckian theory predicts that the non-conscious presentation of a relative will trigger the automatic system that makes relatives seem sexually unattractive, with the knock-on effect that the strangers' faces would be rated as less attractive. Contrary to this prediction, the students who were subliminally presented with a family member actually rated the strangers' faces as more attractive than did the control students.

In a second study, 40 students rated the sexual attractiveness of faces that either had or hadn't been morphed to varying degrees to resemble their own face (a way of simulating genetic relatedness). The students presented with the morphed faces rated them as more sexually attractive than did control students who viewed unaltered faces, and the greater the morphing, the greater the perceived attractiveness. This appears to be consistent with Freud's claim that we really are attracted to our relatives, and it also chimes with past research showing that we tend to marry people who look similar to ourselves - a phenomenon known as homogamy.

For the final study, a group of students once again rated the sexual attractiveness of strangers' faces. This time half the students were told falsely that some of the faces had been morphed to resemble them, as a way to simulate genetic relatedness. The students fed this lie subsequently rated the faces as less attractive than the control students who thought they were simply rating strangers' faces. The finding appears to support Freud's contention that it is the incest taboo that causes us to find people who we think we're related to, less attractive.

Fraley and Marks say their findings are largely in keeping with Freud's writings, whilst being at odds with Westermarckian evolutionary psychology. However, whereas Freud referred to unconscious desires, Fraley and Marks think our attraction to our relatives could be triggered by a kind of human sexual imprinting, according to which our sexual preferences are shaped by our early experiences, or by mere familiarity, or both. The point about familiarity refers to a well established finding in psychology that we tend to find things that are more familiar more appealing.

The influences of imprinting and familiarity are balanced out, Fraley and Marks suggest, by the cultural deterrent of the incest taboo and also by habituation - the tendency for excessive familiarity to breed indifference or contempt. Indeed, the deterring influence of taboo and habituation could explain the finding that people are less likely to mate with a person with whom they are reared, even if that person is unrelated (this is known as the Westermarck effect).

Fraley and Marks call their approach to this topic the evolutionary psychodynamic perspective. 'From this point of view,' the researchers said, 'one reason Oedipus longed for (and eventually married) his mother in the myth of Oedipus Rex is because she was related to him. His desire was possible, however, only because he was unaware of his true relationship to her.'

ResearchBlogging.orgFraley RC, & Marks MJ (2010). Westermarck, freud, and the incest taboo: does familial resemblance activate sexual attraction? Personality and social psychology bulletin, 36 (9), 1202-12 PMID: 20647594

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.


Jane said...

That adults who were adopted as infants and then meet their birth siblings not uncommonly find that there is a sexual attraction fits with Freud's view in that they are attracted to each other, but not being habituated because they were reared apart often find it difficult to obey the social taboo against incest. This is so common that awareness raising discussion of the possibility of sexual attraction is commonly part of the counselling offered to adoptees before contact is made with their birth family.

LemmusLemmus said...

Another article calling Westermarck into question:

Vitosh said...

Could the subliminal images of relatives have the anchoring effect on subjects?
Subjects would unconsciously compare the photos of strangers to their relatives. The stranger's faces are relatively rated as more attractive because the kin's faces are perceived as unattractive.

Nora Miller said...

It seems to me that this might stem from the imperative on "lower" animals to breed with members of their own species. When several similar species live in proxmity (sparrows, for example, or some of the smaller monkey species) you need to recognize the subtle cues that separate your species from the other. That, in combination with learning about self and other by watching "mom and dad" and others in our "clan", would seem to suggest that this preference for relatives goes way way back in our genetic makeup. Basically the rule for picking a mating partner would be "the more like me, the more likely to be my species." I would think it would have evolved long before humans even existed as a species, before the evolution of human brains that could and would learn to make even finer distinctions, between groups within our own species. Maybe?

Michael Meadon said...

A single study, with a tiny number of participants, the results of which have no one unambiguous presentation, a refutation of an entire research literature not make.

Paint me unimpressed.

Neuroskeptic said...

Isn't it also possible that the subliminal family members made people judge the test pics more positively, which they interpreted as sexual attraction (because they were asked to rate attractiveness)?

E.g. if you'd asked them to rate trustworthiness, or friendliness, or intelligence, or anything else "good", I bet you'd get the same result.

GamingLifer said...

@ Michael, Neuro: You didn't even read the article, did you?

Alex said...

Freud has a psychoanalytical mindset and a lot of people disagree with that. So I see why people would think he was wrong. He was also kind of a nutcase. Psychoanalytical studies are usually controversial and maybe there should have been more studies but the theory has been around for quite some time and it's always going to be something that people disagree with. I think people do subliminally have an attraction for family members or people resembling their family members, not only with looks but with personalities too. It was when we made incest a taboo that people denied those feelings of attraction.

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