Month: May 2007

Prospect magazine has an engaging article by psychologist Judith Rich Harris who argues, contrary to popular belief, that parents are not the most important influence in a child’s development.

Harris wrote a book called The Nurture Assumption, and more recently No Two Alike, that both took a similar line, suggesting that the influence of the home environment is relatively small in shaping a child’s personality.

She bases this on research suggesting that children can and do adapt their behaviour according to whether they’re with their parents, with others, in the home, or otherwise.

Harris suggests that child behaviours that remain the same across various environments are more likely to be influenced by genetics.

In other words, she argues that the idea we relate to others in specific ways because we’ve learnt certain core relationship styles with our parents is mistaken, and in fact, we develop context and person specific relationship patterns that can be seen even from an early age.

She gives the example of the classic distinction made between the personalities of first and last born children:

Firstborns and laterborns do behave in characteristic ways when they’re in the presence of their parents and siblings, but they drop these behaviours when they’re away from their family. Like James in [TV programme] Child of our Time, they adapt their behaviour to their setting. The firstborn who dominates his younger siblings at home doesn’t automatically assume that he will also be able to dominate his classmates. After all, even though he’s the largest child at home, he may turn out to be the smallest one in the playground. Research confirms that firstborn children are, on average, no more dominant in the playground than are laterborns. Nor do laterborns go through life permanently cowed. A laterborn who is pushed around by his older brother at home is fully capable of stepping into a dominant role with his peers.

Link to Prospect article ‘Why home doesn’t matter’.
Link to Wikipedia page on Judith Rich Harris with many links.

Zimbardo’s famous ‘Stanford Prison Experiment‘ is often cited as an example of where circumstances influence average people to take up abusive roles.

In a recent article in Personality and Social Psychology Bulletin, psychologists Thomas Carnahan and Sam McFarland tested the idea that the people who volunteer for this sort of study were truly ‘average’ and found that they had character traits that could encourage abuse.

To recruit participants, the researchers used the newspaper advert from the original Stanford Prison Experiment, as well as another advert that was identical, except for the mention of ‘prison life’.

They found that volunteers who responded to the advert that mentioned ‘prison life’ scored significantly higher on measures of the abuse-related dispositions of aggressiveness, authoritarianism, Machiavellianism, narcissism, and social dominance and lower on empathy and altruism.

This suggests that circumstances may not be the only factor in influencing the sort of behaviour seen in the original study, as some people may have particular attitudes that could make abuse more likely when the circumstances allow for it.

There is further commentary and analysis of the research over at the ever-excellent CrimePsychBlog.

Link to CrimePsychBlog on ‘Revisiting the Stanford Prison Experiment’.
Link to abstract of research study.

The current issue of the International Journal of Geriatric Psychiatry has a curious letter about a patient who had the delusional belief that emails were being delivered directly to her mind:

Dear Editor

We report the case of an elderly lady with no experience of using a personal computer or internet technology, whose delusional experiences included the direct personal receipt of email.

Ms T, an 84-year old female with a 40-year history of schizoaffective disorder, presented with a delusional belief that something precious and of value ‘for all people’ had been inserted into her body by a doctor in Germany in the 1950s. She had sought medical help because she believed that an abdominal operative procedure would be necessary to remove a “rat and a teddy bear made of diamonds” that she believed had grown within her.

Following admission, she remained highly guarded, distressed and preoccupied with the need of urgent surgery, which she demanded every time she met her medical team. When asked about the origins of this belief and her desire for surgery, she said that she had gained knowledge about this from a friend, whom she had seen last in 1945.

She explained that she received emails from this friend. These arrived in her mind, exactly like electronic mail, but were managed without a computer. Rather than receiving messages in text form, she received what she described as ‘an impression in my mind’, which conveyed an unequivocal meaning to her. She also believed that her friend had some valuable information for the medical team and that he would be able to contact the senior physician by a similar mechanism.

Following 4 weeks of treatment with risperidone 1.0 mg bd her mental state improved to the point where she stopped receiving the emails, gained insight into her primary belief and told us that she was satisfied that surgery was no longer needed.

There have been previous reports of delusions specific equipment components (Schmid-Siegel et al., 2004) and general activity in the internet (Tan et al., 2004). Most reported cases tend to be in young people, often with a particular experience in using the internet (Bell et al., 2005). To our knowledge, there have been no previous reports of the particular delusion of email receipt by the self. Our case shows that internet-based delusions are not restricted to the young or to those familiar with use of the internet.

Dr Malgorzata Raczek
Prof Robert Howard

Link to PubMed entry for letter.

Dr Petra Boyton casts a critical eye on recent media stories suggesting that sex on first date releases ‘brain hormones’ that increase trust and intimacy that might improve the long-term chances of a relationship. So what does neuroscience tell us about the link?

The claim is made by Dr Barry Gibb [insert Bee Gees joke here] in a new book The Rough Guide to the Brain.

The claim is likely based on the fact that the hormone oxytocin has been reported to increase trust in humans when deliberately administered by experimenters, and has been linked to sexual response in humans.

The trouble is, the evidence for a strong and consistent link with sexual response isn’t really there yet.

A recent review article examined the role of hormones in sexual arousal and looked specifically at oxytocin, noting that:

Carmichael et al. (1987) found that plasma OT [oxytocin] increased around the time of orgasm in men and women, remaining raised for at least 5 min after orgasm…. In a recent study of men, OT increased in some subjects following ejaculation, but the individual variability was such that the group effect was not significant (Kruger et al. 2003a).

Murphy et al. (1987) reported an increase in OT in men during sexual arousal, which persisted beyond ejaculation, but with no obvious increase at ejaculation. In a study of women, Blaicher et al.(1999) found an increase in OT 1 min after orgasm, but levels were close to baseline by 5 min post-orgasm.

It is difficult to draw clear conclusions from this literature on OT and sexual arousal. Whether the increase of OT around orgasm, which has been somewhat inconsistently observed in the human literature, has any specific function, rather than being an epiphenomenon of other changes, remains uncertain…

In other words, the evidence for oxytocin being released consistently during sex is mixed and its significance is unclear.

Even if sex and the oxytocin ‘trust boost’ was reliably linked, you would need to do a study looking at whether couples trust each other more after having sex for the first time to really be sure whether the effect actually had an impact.

Sex causes such a strong behavioural, psychological and neurochemical change that a small release of oxytocin might be completely insignificant among the storm of other effects.

So does sex on first date increase the chances of a long-term relationship?

We don’t know, and what we do know about the neuroscience of sexual response doesn’t really tell us either.

UPDATE: Susan Kuchinskas has added some insightful commentary to this post. Check the comments section.

Link to Dr Petra Boyton’s article.
Link to full text of scientific article ‘The endocrinology of sexual arousal’.