Attraction runs in the family

The ‘incest taboo‘ is the aversion to being sexually attracted to our own family and evolutionary psychology has suggested it is an inherited adaptation to promote genetic diversity. A brilliant study just published in the journal Personality and Social Psychology Bulletin provides evidence that this is actually a cultural phenomenon, received wisdom if you like, because when awareness of the relationship is hidden, people find individuals who resemble their family more sexually attractive.

The debate about whether the incest taboo is an evolutionary adaptation or a cultural practice has quite a vintage as it became a point of contention between the followers of Edvard Westermarck, the Finnish anthropologist, and Sigmund Freud, the Austrian sex obsessive.

Westermarck believed the practice was an adaptation, based on the fact that it seems to occur universally, whereas Freud believed it was a cultural practice and that, actually, we all have incestuous desires that we typically repress – something now famous as the Oedipus complex.

More modern theories of incest avoidance have suggested that they rely on cognitive processes that judge how related someone might be based on our knowledge and our perception of similarity that may signify a genetic relationship.

However, the picture is a little muddied by the fact that recent psychology studies have shown that we are more likely to be attracted to people we are familiar with and that, to some extent, we are more attracted to people who are physically similar to us.

This new study, by psychologists Chris Fraley and Michael Marks, set out to tackle the issue by seeing how subliminal exposure to closely related people would affect sexual attraction.

In an initial experiment, participants were asked to provide a photo of their parent to the researchers. During the study, they were asked to simply rate the attractiveness of strangers’ faces presented to them on a computer.

What they didn’t know was that just before they saw each face, half of the participants had the photo of their opposite-sex parent quickly flashed up on-screen – so quickly, in fact, that it was too fast to take in consciously. The other half, were given a subliminal image of someone else’s parent.

Those who were subliminally shown their opposite-sex parent rated the subsequent face as significantly more attractive, suggesting that their sexual interest had been slightly raised by subliminal exposure to their mother or father.

The researchers decided to go further by seeing how attraction would be affected if the person was exposed to images of themselves – after all, someone who shares 100% of their genetic material.

For this study this they used a technique called morphing to make images that had been digitally manipulated to be composites of two distinct faces – the person’s own and a stranger’s – to varying amounts. The participants were asked to rate the attractiveness of the faces, each of which ranged from being 0% their own face to a blend of 45% their face and 55% stranger.

The mix was never enough so the participants could tell that the faces were blended with their own, but they consistently rated faces that had more of themselves as more attractive.

A final experiment did exactly the same, but with an additional group who were told their own faces had been blended into the photos and that the study was investigating incest and attraction to faces that are designed to resemble genetic relatives.

The group who were aware what was happening showed exactly the opposite behaviour, they were less sexually attracted to faces that they more closely resembled.

In other words, the aversion to people we have a relation to may be based in conscious awareness, not an unconscious evolutionary adaptation.

This suggests is that Freud may have been right when he suggested that there may be an element of attraction to people in our own family.

The researchers doubt that we need to accept the full ‘Oedipus complex’ theory to make sense of this, but simply that the psychology of familiarity, bonding and attraction begins to develop in the family environment and so we retain an element of attraction to people we learnt about love with.

However, for sensible reasons, as a society we need to make sure we form new romantic relationships with people outside our immediate families, and so have instilled this knowledge in our culture.

Link to PubMed entry for study.

There’s a party in my dream and everyone’s invited

The consistently amusing NCBI ROFL blog has found a fantastic case study, originally published in Sleep Medicine, of a woman who started sending emails during sleeping-walking episodes when her dose of sleeping pill zolpidem was increased.

As we’ve discussed previously, zolpidem has an association with unusual sleepwalking behaviours, but sending email invitations to dream parties is apparently a first.

Brilliantly, the case report contains copies of the emails (a bit strangely, both are printed out and scanned in). The party invite is just wonderful.

The case description is as follows:

We describe a case of a 44-year-old woman with idiopathic insomnia almost all her life. She tried various medications, psychotherapy and behavioral techniques for the treatment of her insomnia without any significant effects. She was started on Zolpidem 10 mg 4 years ago. She was able to sleep 4–5 h each night, but then the effects started wearing off. She increased the dose of Zolpidem by herself to 15 mg every night; she would take 10 mg tablet around 10 p.m. and 5 mg around 3 a.m.

With this regimen she started sleeping for 5 h every night and felt alert during the daytime. After increasing the dose, she began to have episodes of sleepwalking. During one such episode, she went to bed around 10 p.m., she woke up 2 h later, and walked to the next room on the same floor. She turned on the computer and connected to the internet. She logged in by typing her user ID and password to her email account. She sent three emails to her friend inviting her to come over for dinner and drinks. Her friend called her the next day to accept the invitation. She said that the emails had strange language. The patient was not aware of these emails. She checked her sent folder and found three emails sent at 11:47 p.m., 11:50 p.m. and 11:53 p.m. They were in upper and lower cases, not well formatted and had strange language. She was shocked when she saw these emails, as she did not recall writing them.

Link to NCBI ROFL post and copy of other sleep email.

A rare glimpse of childhood schizophrenia

The LA Times has an article and video about a young girl who has one of the very rare cases of childhood schizophrenia. In this instance, it is particularly unusual because the affected child is only six years old.

One of the biggest mysteries in psychiatry is why psychosis, the occurrence of delusions and hallucinations, doesn’t typically first appear until about 17 years of age for males and about 20 for females.

It’s curious because from a psychological perspective, all the things that are supposed to ‘go wrong’ – thinking, belief, perception, motivation, emotion – are already in place many years before.

To give a clumsy example, it would be like finding out that kids never broke their arms until they were teenagers, despite having perfectly functional limbs for years before.

There are some clues from studies of ‘neural migration’ that have shown that people with schizophrenia, on average, don’t show the same patterns of connections between cortical layers in the frontal lobes – which are built during brain development and continue maturing well in the early 20s.

However, these are still no more than clues, as no-one has a well worked-out idea of how this explains the fact that psychosis doesn’t typically appear until early adulthood.

In very rare cases, however, psychosis does seem to appear earlier – like in the early teenage years – and in rarer cases still, it appears in children younger than 12.

Clearly, kids have a rich fantasy life and imaginary friends are normal (and, in case you’re worrying, are usually associated with better adjustment later in life). In addition, some kids are just a bit eccentric. This can make it difficult to say for certain whether, for example, a child is hallucinating or just being whimsical.

But despite these difficulties, there are some kids who do seem to have persistent troubling delusions and hallucinations along similar lines to schizophrenia.

These occasional cases pose something of a challenge for psychiatrists, not least because the first-line treatment for schizophrenia, antipsychotic drugs, have some rather nasty side-effects, but also because very few studies have tested the effectiveness of these medications in children.

One study that has been doing this, however, is the Treatment of Early-Onset Schizophrenia Spectrum (TEOSS) study, which just reported it latest results.

Sadly, they are a huge disappointment for anyone hoping for a easy solution as they showed that the pills generally caused more problems than they solved, produced serious health risks, and were poorly in dampening down the delusions and hallucinations.

From a more personal angle, the LA Times piece is both a rare look at the condition and a rarer look into the emotional life of a family trying to make sense of their child’s unpredictable and sometimes distressing world.

Link to LA Times piece on childhood schizophrenia.

The blessed neuroscientist

Neurosurgery has an article on the 17th Century neuroanatomist Niels Stensen who not only made major contributions to our understanding of the brain but was beatified – the first step to becoming a saint – by Pope John Paul II in 1988.

His work was not restricted to the brain and was a founding figure in both geology and palaeontology, but his willingness to test received wisdom with regard to brain anatomy led him to overturn some key assumptions of the time:

Stensen contested the anatomic assumptions of Descartes’ description of the pineal gland. In L’Homme, Descartes depicted the human body as a machine controlled by the soul, the seat of which was the pineal gland. Descartes described the pineal gland as a mobile structure, surrounded by small arteries and suspended in the ventricles. Although Stensen admired Descartes’ philosophical method, his careful dissection neatly demonstrated the anatomic errors of Descartes on pineal gland, finally solving the ‚Äúmost famous anatomic dispute which this age has produced‚Äù.

Sadly, it was not his work on the pineal gland which earned his holy promotion but his decision to pack in science to become a bishop.

However, the final outcome was much the same as he died in poverty wandering from place to place trying to engage the public.

Link to Neurosurgery on Niels Stensen.

Purple haze: paint huffing hallucinations differ by hue

Photo by tanakawho. Click for sourceAdolescent solvent abusers reported that different colours of paint cause different types of hallucinations, according to a remarkable study just published in Drug and Alcohol Review.

The research, led by Michael Takagi from the University of Melbourne, was only a small study of 16 young people who sniffed spray paints, but the results are quite striking.

Although all users reported similar levels of pleasure, all those who preferred chrome paint (gold, chrome and silver) reported they used it for the vivid, detailed visual and auditory hallucinations while those who preferred non-chrome paint rarely experienced changes in perception.

The briefly described experiences are as heartbreaking as they are curious:

For example, one young inhalant user had been removed from her home and placed in residential care. She found the situation difficult and did not assimilate well with her housemates, who had also been removed from their homes. Every day, she would go behind the fence of her residential unit and sniff CP [chrome paint]. She reported that faces would appear out of the wooden fence and talk with her, and she felt that these were her only friends. In contrast, another young inhalant user particularly enjoyed playing video games that were available in his residential unit. However, he was only allowed to play for specific amount of time each day. After sniffing CP, he would hallucinate that he was the hero of the video game.

Furthermore, all of the chrome paint users reported that the hallucinations they experienced differed between colours, whereas only a third of the non-chrome paint users said this was the case.

The study didn’t enquire exactly how the experiences differed between colours, and it can’t say how much the differing reported effects are due to different paint ingredients or simply due to their psychological associations, as it was just a survey of effects.

Link to study summary on PubMed.

The illusion of progress lights a fire

Psychologists have longed talked about ‘goal gradient’ which describes how we work harder to achieve a goal as we get closer to it. I just came across a fantastic study published in the Journal of Marketing Research which shows that we can be convinced to shift into a higher gear of work and spending, even when the perception of progress is a complete illusion.

The ‘goal gradient hypothesis’ was original discussed in the 1930s with regards to rats in mazes, based on the observation that the animals ran more quickly when they got nearer the end.

Ran Kivetz and colleagues wondered whether this would apply to shopping behaviour and ran a series of experiments to show that this was the case.

One was to see how quickly people with ‘coffee shop loyalty cards’ would fill up their cards as they got nearer to the ‘buy ten get one free’ goal. Sure enough, the last few stamps were acquired more quickly than the first ones.

But here’s the clever bit. They did an experiment where they gave some customers a ‘buy ten get one free’ card, while others got a ‘buy twelve get one free card’ but with the first two stamps already filled in.

In practical terms, the loyalty scheme was identical, but the customers bought coffees more quickly to full up the ‘buy twelve’ cards in less time – in line with ‘goal gradient hypothesis’ – despite the fact that the actual progress towards the goal was no different.

The researchers call this the ‘illusory goal progress’ effect and shows that our perception of how close we are to achieving something can be easily manipulated by shifting the goal posts.

The full study is available online as a pdf and Kivetz discusses the study (albeit in passing) on a recent ABC Radio National programme on ‘Reward, regret and consumer behaviour’.

Link to study summary.
pdf to scientific paper.
Link to ABC RN on ‘Reward, regret and consumer behaviour’.

An eccentric history of headache treatments

Neuroscience journal Brain has an amazing article on the history of non-drug treatments for headaches. What sounds like a dry article on the history of neurology is actually a remarkable romp through many of the most eccentric treatments in medicine.

The piece has just been published online and sadly is locked behind a paywall (keeps the riff-raff out) but here are a couple of interesting excerpts. The first, completely terrifying, the second, somewhat more calming.

To start, a scorching treatment for headache from Ancient Greek physician Aretaeus of Cappadocia:

‘Consequently, you have to shave off the hair (which yet on its own is good for the head) and cauterize [burn] superficially down to the muscles. If you wish to cauterize down to the bone, carry it out at a site where there are no muscles. For if you burn muscles, you will provoke cramps. Some physicians incise down to the bone on the forehead along the border of the hair. They abrade or chisel the bone down to the diploe and let flesh grow over the place. Others perforate the bone down to the meninges. These are hazardous treatments. You have to apply them when the headache persists after all that has been done; the patient keeps courage and the body is vigorous’

…and relax. Needless to say, there were also some slightly more gentle treatments from times gone past (assuming you’re not a mole).

Oribasius, mentioned above, advised the injection of soft oil into the ear. An interesting treatment for headache was that recommended by the 10th century astronomer and physician Ali ibn Isa (ca. 940–1010 CE), who recommended binding a dead mole to the head. If diseases of the head occur because of a faulty warm constitution, Maimonides advised bathing in comfortable warm sweet water, because it dissolved the sharp vapours that rose to the head and improved the body disposition. If headache was localized, it was most appropriate to apply massage with oil of roses

By the way, the image at the top of the post is an ‘nerve vibrator’ taken from Mortimer Granville’s 1883 book Nerve-Vibration and Excitation as Agents in the Treatment of Functional Disorder and Organic Disease.

The article is packed full of such snippets and is worth checking out if you can get hold of a copy through a library or by emailing the authors.

Link to DOI entry and summary.