Gender differences in human orgasm

An interesting excerpt from a recent scientific paper entitled “Toward an understanding of the cerebral substrates of woman’s orgasm”, published in the August edition of Neuropsychologia:

Since the pioneering research of Kinsey and then of Masters and Johnson, there has been considerable discussion about the differences between female and male orgasm. While orgasms are physiologically the same in males and females, it has often been assumed that there are two distinct and easily distinguishable kinds of subjective experiences (Vance & Wagner, 1976).

This assumption is mostly based on the basic physical disparities between male and female orgasm concerning the orgasm duration. For example, it is agreed that a man’s orgasm is often more sudden and explosive in nature while a woman’s orgasm is more prolonged and less violent (Meston et al., 2004; Vance & Wagner, 1976).

However, a study investigating the basic differences between a man’s and a woman’s orgasm experience by submitting 48 written descriptions of orgasm (24 men and 24 women) to 70 judges, demonstrated that subjective experience of orgasm do not differ by gender (Vance & Wagner, 1976).

In this study, the judges (obstetrician-gynecologists, psychologists, and medical students) had to sex-identify the descriptions and to discover whether sex differences could be detected. The judges could not correctly identify the sex of the person describing an orgasm. Furthermore, male judges did no better than female judges and vice versa.

This suggests that men and women share common mental [cognitive] experiences during orgasm. Whether this is the case at the neurological level is a matter for current neuroimaging data.

An interesting paper which I shall try and write about more when I get the chance.

Link to abstract of scientific paper.

Statistical self-defence over at idiolect.org.uk

Readers of mindhacks.com might be interested to read my review of the last chapter of Darrell Huff’s classic How To Lie With Statistics, over at my personal blog idiolect.org.uk. The last chapter gives Huff’s rules of thumb for interrogating statistics and I’ve provided some slim commentary on the workings of science, reason and whatnot. See you there!

Everywhere like such as

I just recorded an interview on psychology and the internet for ABC Radio National’s All in the Mind. Natasha Mitchell was completely charming, the questions informed and on target, but as for me, Miss South Carolina, I know how you feel.

Also, I’m off to the British Association of Cognitive Neuroscience conference for a couple of days, as I’ve kindly been asked to speak in the cognitive neuropsychiatry symposium in honour of the late great Prof Hadyn Ellis. Apologies if the updates are a bit patchy. Not sure how internet access is going to work out.

Brain scan entrepreneurs

The New York Times has an article on the burgeoning business of commercial fMRI brain scan services – that offer to do everything from detecting lies to managing pain.

fMRI is a type of scan that can map levels of oxygen-rich blood across the brain. As brain areas need more oxygen the harder they work, fMRI can produce a map of inferred activity.

fMRI is a relatively new technology. Although its now the most popular technique for tracking brain function, it only became widespread in the mid to late-1990s.

We’ve just got to the stage where commercial companies are beginning to sell fMRI-based services.

So far, the offerings are almost entirely based on experimental results that most scientists find interesting but preliminary, and to different degrees, the glitz of neuroscience, and impressive but scientifically meaningless publicity stunts.

This isn’t really a problem with the technology itself. It’s common for companies to sell their product while its still in development, but its worth bearing in mind when you hear the more outrageous claims for what it can do.

You might think that this business is so new and specialised as to be a target for easy-money investors, but it’s surprisingly cut-throat.

For example, VSM MedTech, makers of MEG brain scanners, seem to be running as a support only company after a serious nose dive.

However, this still leaves two other companies who can currently manufacture and install these multi-million pound devices.

The NYT article surveys the sorts of commercial brain scan services currently being offered, and has a critical commentary on some of the companies’ claims.

Link to NYT article ‘Mind Over Matter, With a Machine‚Äôs Help’ (via BB).

Encephalon 30 sends off Neurofuture

The 30th edition of the Encephalon psychology and neuroscience writing carnival has just hit the net – as the last ever post on brain blog Neurofuture.

Luckily, Neurofuture author Sandra is still going to be writing for Omni Brain, PsychCentral and print publications, so it’s less a departure and more a regrouping.

A couple of my favourites from this month’s edition include a post on the how hemispheres of the brain can be specialised for certain tasks, and a video discussion on ‘Is Consciousness Definable?’.

There’s more at the link below.

Link to Encephalon 30.

Girls with autism

The New York Times has an in-depth article on autism in girls, a topic largely neglected in the research literature owing to the fact that males are much more likely to be diagnosed with the condition.

It’s only recently that researchers have started to look in earnest into differences between boys and girls with autism.

Generally, the studies find that there are no major differences in the core aspects of autism between the sexes. But as a diagnosis of autism relies on these aspects, by definition, they’re going to be largely the same.

Studies looking at brain structure, cognitive abilities, and other types of everyday problem and emotional disturbance, have found some key differences though, and it seems they sometimes affect girls particularly negatively:

No doubt part of the problem for autistic girls is the rising level of social interaction that comes in middle school. Girls’ networks become intricate and demanding, and friendships often hinge on attention to feelings and lots of rapid and nuanced communication ‚Äî in person, by cellphone or Instant Messenger. No matter how much they want to connect, autistic girls are not good at empathy and conversation, and they find themselves locked out, seemingly even more than boys do. At the University of Texas Medical School, Katherine Loveland, a psychiatry professor, recently compared 700 autistic boys and 300 autistic girls and found that while the boys’ “abnormal communications” decreased as I.Q. scores rose, the girls’ did not. “Girls will have more trouble with social networks if they’re having greater difficulty with communication and language,” she says.

The article is a well-researched tour through some of the latest research on girls with autism, but also has some wonderful illustrations of how girls with autism experience the complex world of social interaction.

Link to NYT article ‘What Autistic Girls Are Made Of’.

Addicted to food?

Scientific American has an interview with neurobiology of addiction tsar Dr Nora Volkow discussing whether we can understand overeating as a form of addiction.

Volkow describes how the reward system, of which the dopamine rich mesolimbic pathway is particularly important, is involved in signalling desire and predicting pleasure.

Needless to say, it plays a key role in addiction. But as it’s involved whenever we do anything pleasurable, from taking drugs to eating to laughing, it’s also central to many non-pathological situations.

In fact, we presume it kicks in when we desire anything pleasurable, to any degree.

So it may be crucial to understand what happens in this pathway in people who have difficulties with over-eating.

Volkow mentions that people with obesity tend to have fewer D2 dopamine receptors in the striatum, perhaps suggesting more food is needed for the same pleasurable response, which could promote over-eating.

A similar thing has been found in addicted drug users, which raises the question, is obesity a ‘food addiction’?

Although not without controversy, drug addiction is usually described as having three main components (the ‘three Cs’): Compulsive use (wanting to do it again), loss of Control (feeling you can’t stop yourself), and continued use despite adverse Consequences (even when you know it’s damaging).

The difficulty is, normal eating fulfils all three criteria. We’re compelled to eat, stopping ourselves is incredibly difficult, and we all continue to eat things we know are bad for us, even when our health suffers.

Notably, Volkow is careful not to describe obesity as an addiction in the interview, although the magazine is quite happy to label it a ‘food addiction’.

Increasingly, we’re finding that problems labelled as separate in the diagnostic manuals can actually have some core features in common.

In this case, similar differences in the reward system in addiction and obesity seem to be important.

However, we always have to beware of over-simplifying complex problems.

Obesity, like high-blood pressure, is simple to define, but is caused by many different things acting together.

Highlighting overlaps can be incredibly powerful, but inappropriately lumping problems together often means missing the other factors which may be equally important.

Scientists are usually pretty good at this, typically discussing the similarities or talking about shared factors, but it’s worth looking out for when the message gets simplified when retold in the press.

Link to SciAm interview on obesity and addiction.

Read this, you sex machine: the birth of PR

I’ve just found a concise piece from NPR radio on Edward Bernays, the nephew of Sigmund Freud, who used his uncle’s ideas on the unconscious to transform advertising into its current form.

Bernays pretty much invented the idea that you can sell products, not by making their practical advantages known, but by associating them with the satisfaction of desires – to be sexy, successful, a good husband or wife, the need to feel safe, well-regarded and so on.

Every time you see razors sold as babe magnets, or perfume sold as booty dust, that’s Bernays’ ideas at work.

He also invented the idea that marketing was more than just adverts. It could also be presented as ‘education’ that had no direct connection with a product but made people more receptive to other marketing.

Almost any sponsored survey or research you see in press, especially if masquerading as science, is based on this idea.

For example, Pfizer fund a survey that says people over 40 are having the best sex. People over 40 not having great sex wonder what they could do about it.

Hey, that’s my favourite B-list celebrity! And he’s telling me that Pfizer sell a pill aimed at the over-40s that claims to improve my sex life. My problem solved, through the power of science!

Of course, it’s not just hard-on pills [note to self: that’s not a phrase I get to use often enough]. It’s now a tried and tested technique that has been used for selling everything from igloos to ideologies.

Indeed, Bernays was personally involved in selling political ideas as well as commercial products. Notably, in his book Propoganda, he argues that this form of manipulation is essential for managing the inherent chaos and destructive forces of society.

Film-maker Adam Curtis cited Bernays as one of the most influential people of the 20th century in his persuasive, if not slightly polemic, four-part series Century of the Self (available online: 1, 2, 3, 4). It contains many more examples of Bernays’ often ingenious PR campaigns.

The NPR piece is a short 10 minute introduction to Bernays’ life and work, and the site has a some additional audio clips of Bernays himself discussing his ideas.

Link to ‘Freud’s Nephew and the Origins of Public Relations’.
Parts one, two, three, four of Century of the Self.
Link to online Bernays exhibit from the Museum of Public Relations.

Pink slip, feeling blue

Ben Goldacre over at Bad Science has written a great analysis of a recent study that suggested we have the traditional ‘pink for girls, blue for boys’ because of evolutionary differences in colour preference.

However, it seems not only are the study’s findings not strong enough to make an evolutionary claim, but that the ‘pink for girls, blue for boys’ idea is relatively recent and hardly as traditional as we like to think.

The data itself is interesting if not a little unspectacular. Men and women from the UK showed different colour preference curves with men showing a preference for bluer shades over women.

In a sample of Chinese participants the preference was much less pronounced and peaked at more redder shades overall.

One of the curses of evolutionary psychology, the science that attempts to work out whether any of our psychological preferences are the result of natural or sexual selection, is that any sex difference is fodder for an evolutionary explanation.

Actually, we know there are definite differences in colour perception between men and women. There’s a great paper that summarises the scientific evidence which available online as a pdf.

There are sex-linked differences in specific genes that are linked to colour perception, which is why men are more likely to be colour blind and perhaps 1% of women may have four, rather than three, colour receptors in the retina.

But as Ben points out, simply finding a sex difference in colour preference really doesn’t tell us anything about genetics or evolution. It could easily just be an effect of culture or fashion.

Link to Bad Science on pink-blue study.
pdf of paper on genetics, sex differences and colour perception.

Dennett on chess and artificial intelligence

Technology Review has published an article by philosopher Daniel Dennett looking at what the development of computer chess tells us about the quest for artificial intelligence.

AI and chess have an interesting and intertwined conceptual history.

It used to be said that if computers could play chess, it would be a genuine example of artificial intelligence, because chess seemed to be a uniquely human game of strategy and tactics.

As soon as computers became good at chess, it was dismissed as a valid example because, ironically, computers could do it. A classic example of moving the goalposts.

Similarly, I’ve recently heard a few people say “If computers could beat us at poker, that would be a genuine example of artificial intelligence”. Recently, a poker playing computer narrowly lost to two pros.

Presumably, ‘genuine intelligence’ is just whatever computers can’t do yet.

Dennett is a big proponent of the “if it looks like a duck and quacks like a duck, it’s a duck” school of behaviour.

In other words, if something can perform a certain task (like playing chess), then objections about it not using the same mechanism as humans to do the task are irrelevant as to whether its doing the task ‘genuinely’ or not.

One of his related ideas is the intentional stance. It says that things like belief, intention and intelligence are not properties of a creature, computer or human, they’re just theories we use to understand how it works.

So if it makes sense for us to interpret a chess computer as having the belief that “taking the queen will give an advantage”, then that’s a good theory for us to work on, but it doesn’t necessarily tell us anything about how that behaviour is implemented in the system.

Link to TechReview article ‘Higher Games’ (via BoingBoing).

Ancient Egyptian post-mortem neurosurgery

Retrospectacle has a great post that describes how the Ancient Egyptians removed the brains of the dead before mummification and notes some of their neurological knowledge.

The Ancient Egyptians described a range of neurological and psychiatric disorders in their writing that would be recognisable today.

One major source is the Edwin Smith papyrus, another is the Ebers papyrus which has quite a significant section on psychiatric disorders, including what we would now class as depression, dementia and psychosis.

Needless to say, the remedies were often magical in nature, but the observation of the clinical features can be quite astute.

The article on Retrospectacle has some great brain scan images and a link to a video of how embalmers would remove the brain through the nose, using a metal tool to go up into the frontal lobes.

Link to Retrospectacle article.

2007-08-24 Spike activity

Quick links from the past week in mind and brain news:

Why are visual memories so vivid when visual memory is so limited? Cognitive Daily has another fantastic breakdown.

Science and Consciousness Review has a new feature article on whether language is necessary for self-awareness.

The New York Times has an article on the potential of physical exercise to boost memory and cognitive processing speed. Pure Pedantry picks up on its off-kilter interpretation.

The BPS Research Digest looks at why we’re rubbish at predicting how what happens will affect us emotionally.

Read the latest and ‘in progress’ research on cognitive training and brain fitness at Sharp Brains.

Apparently, we have taste receptors in the gut!

Drug company AstraZenenca have been whitewashing the entries for their drugs on Wikipedia. Bears still shitting in woods.

PsyBlog notes that pessimists have good reason to be pessimistic. People prefer optimists and realists!

The New York Times discusses the importance of getting a therapist you click with to get the most out of psychological treatment.

Mr. Freeze, the Iced-Time Demon. A thought-provoking thought experiment from philosopher Pete Mandik

Is there anything good about men? Psychologist Roy Baumeister’s speech notes that males are much less likely to reproduce than females, and wonders what evolutionary effect this has had on gender psychology.

Jose Padilla’s conviction raises questions about whether detainees who undergo extreme isolation can be given fair trials, according to In These Times.

More on the wonderful ACHOO syndrome that won our AAICS competition.

Induced out-of-body experiences: Do try this at home

Science has just published two short papers where researchers induced a touch sensation that that seemed to be felt in a ‘fake’ body that appeared to be several metres in front – similar to an ‘out-of-body-experience’.

The two studies were developed independently but both involved the same idea. In one study, the person was filmed from behind while they had their back stroked. They also wore a special head-mounted display that showed them what the video camera saw.

In other words, they saw their back being stroked as if they were sitting behind themselves and their body was in front of them. After a while, the sensation seemed to be move from their own back to be located in the projected body in front.

Neurophilosopher has found a fantastic video of Prof Olaf Blanke explaining the experiment, which is a wonderful introduction.

The other study did something very similar but used touches to the chest.

While these two studies have demonstrated the effect in a most striking way, the effect isn’t new, as it’s often been demonstrated with the ‘rubber hand illusion‘.

In fact, you can do something similar at home, and make touch sensations seem as if they are located in inanimate objects:

This is taken from Hack #64 (‘Mold your Body Schema’ [pdf]) from the Mind Hacks book, but was originally inspired by a similar exercise in Ramanchandran and Blakesee’s book Phantoms in the Brain:

Sit at a table with a friend at your side. Put one hand on your knee, out of sight under the table. Your friend‚Äôs job is to tap, touch, and stoke your hidden hand and‚Äîwith identical movements using her other hand‚Äîto tap the top of the table directly above. Do this for a couple of minutes. It helps if you concentrate on the table where your friend is touching, and it’s important you don’t get hints of how your friend is touching your hidden hand. The more irregular the pattern and the better synchronized the movements on your hand and on the table, the greater the chance this will work for you. About 50% of people begin to feel as if the tapping sensation is arising from the table, where they can see the tapping happening before their very eyes. If you’re lucky, the simultaneous touching and visual input have led the table to be incorporated into your body image.

All of these experiments synchronise the touch with visual movement, but put these perceptions in conflict with visual information about where the synchronisation is happening.

The brain attempts to resolve this conflict by prioritising the visual system, which is relatively information rich in comparison to our other senses.

Notably, these new studies are the first to demonstrate something akin to an ‘out-of-body-experience’.

It’s not really the same as the classic experience where you see your body in front of you, perhaps as you float above it, something known as autoscopy or heautoscopy in the medical literature.

However, as we reported last year, Prof Olaf Blanke’s team have studied various types of ‘out-of-body’ and ‘projected self’ experiences, either caused by direct brain stimulation, or after neurological disorder.

The lab’s publications page has many of their papers available as full-text articles if you want more detail.

Link to video interview and explanation of experiment.
Link to New Scientist write-up.
Link to previous Mind Hacks article on Blanke’s and colleagues studies.
pdf to Hack #64 ‘Mold your Body Schema’.

Drug testing whole cities

USA Today is reporting that a toxicology team have developed a method for drug testing a city’s water supply, indicating the level at which certain drugs are being used by the population.

The study was reportedly led by environmental toxicologist Prof Jennifer Field and was presented at the 2006 American Chemical Society conference.

The technique apparently involves taking a sample of water from the city’s sewer plant, and so doesn’t identify individuals, but can estimate the proportions of different drugs in the water to give a guide to which drugs are being used in what quantities.

The science behind the testing is simple. Nearly every drug — legal and illicit — that people take leaves the body. That waste goes into toilets and then into wastewater treatment plants.

“Wastewater facilities are wonderful places to understand what humans consume and excrete,” Field said.

In the study presented Tuesday, one teaspoon of untreated sewage water from each of the cities was tested for 15 different drugs. Field said researchers can’t calculate how many people in a town are using drugs.

She said that one fairly affluent community scored low for illicit drugs except for cocaine. Cocaine and ecstasy tended to peak on weekends and drop on weekdays, she said, while methamphetamine and prescription drugs were steady throughout the week.

Field said her study suggests that a key tool currently used by drug abuse researchers — self-reported drug questionnaires — underestimates drug use.

“We have so few indicators of current use,” said Jane Maxwell of the Addiction Research Institute at the University of Texas, who wasn’t part of the study. “This could be a very interesting new indicator.”

Unfortunately, it seems the American Chemical Society charge for access to the summaries of their conference presentations, but Scientific American has a little more detail on the procedure.

The news is reminiscent of a 2004 Environmental Agency study that found Prozac in UK sewage (incorrectly reported as the ‘Prozac found in drinking water’ story).

Link to USA Today article (via AADT).
Link to SciAm write-up.