Are women and men forever destined to think differently?

By Tom Stafford, University of Sheffield

The headlines

The Australian: Male and female brains still unequal

The International Institute for Applied Systems Analysis: Gender disparities in cognition will not diminish

The Economist: A variation in the cognitive abilities of the two sexes may be more about social development than gender stereotypes

The story

Everybody has an opinion on men, women and the difference (or not) between them. Now a new study has used a massive and long-running European survey to investigate how differences in cognitive ability are changing. This is super smart, because it offers us an escape from arguing about whether men and women are different in how they think, allowing us some insight into how any such differences might develop.

What they actually did

Researchers led by Daniela Weber at Austria’s International Institute for Applied Systems Analysis analysed data collected as part of the European Survey of Health, Ageing and Retirement. This includes data analysed in this study from approximately 31,000 adults, men and women all aged older than 50. As well as answering demographic questions, the survey participants took short quizzes which tested their memory, numeracy and verbal fluency (this last item involved a classic test which asks people to name as many animals as they could in 60 seconds). Alongside each test score, we have the year the participant was born in, as well as measures of gender equality and economic development for the country where they grew up.

What they found

The results show that as a country develops economically, the differences in cognitive ability between men and women change. But the pattern isn’t straightforward. Differences in verbal fluency disappear (so that an advantage on this test for men born in the 1920s over women is not found for those born in the 1950s). Differences in numeracy diminish (so the male advantage is less) and differences in memory actually increase (so that a female advantage is accentuated).

Further analysis looked at the how these differences in cognitive performance related to the amount of education men and women got. In all regions women tended to have fewer years of education, on average, then men. But, importantly, the size of this difference varied. This allowed the researchers to gauge how differences in education affected cognitive performance.

For all three abilities tested, there was a relationship between the size of the differences in the amount of education and the size of the difference in cognitive performance: fewer years of education for women was associated with worse scores for women, as you’d expect.

What varied for the three abilities was in the researchers’ predictions for the situation where men and women spent an equal amount of time in education: for memory this scenario was associated with a distinct female advantage, for numeracy a male advantage and for verbal fluency, there was no difference.

What this means

The thing that dogs studies on gender differences in cognition is the question of why these differences exist. People have such strong expectations, that they often leap to the assumption that any observed difference must reflect something fundamental about men vs women. Here, consider the example of the Australian newspaper which headlined their take on this story as telling us something about “male and female brains”, the implication being that the unequalness was a fundamental, biological, difference. In fact, research often shows that gender differences in cognitive performance are small, and even then we don’t know why these differences exist.

The great thing about this study is that by looking at how gender differences evolve over time it promises insight into what drives those difference in the first place. The fact that the female memory advantage increases as women are allowed more access to education is, on the face of it, suggestive evidence that at least one cognitive difference between men and women may be unleashed by more equal societies, rather than removed by them.

Tom’s take

The most important thing to take from this research is – as the authors report – increasing gender equality disproportionately benefits women. This is because – no surprise! – gender inequality disproportionately disadvantages women. Even in the area of cognitive performance, this historical denial of opportunities, health and education to women means, at a population level, they have more potential to increase their scores on these tests.

Along with other research on things like IQ, this study found systemmatic improvements in cognitive performance across time for both men and women – as everyone’s opportunities and health increases, so does their cognitive function.

But the provocative suggestion of this study is that as societies develop we won’t necessarily see all gender differences go away. Some cognitive differences may actually increase when women are at less of a disadvantage.

You don’t leap to conclusions based on one study, but this is a neat contribution. One caveat is that even though indices such as “years in education” show diminished gender inequality in Europe, you’d be a fool to think that societies which educated men and women for an equal number of years treated them both equally and put equal expectations on them.

Even if you thought this was true for 2014, you wouldn’t think this was true for European societies of the 1950s (when the youngest of these study participants were growing up). There could be very strong societal influences on cognitive ability – such as expecting women to be good with words and bad with numbers – that simply aren’t captured by the data analysed here.

Personally, I find it interesting to observe how keen people are to seize on such evidence that “essential” gender differences definitely do exist (despite the known confounds of living in a sexist society). My preferred strategy would be to hold judgement and focus on the remaking the definitely sexist society. For certain, we’ll only get the truth when we have an account of how cognitive abilities develop within both biological and social contexts. Studies like this point the way, and suggest that whatever the truth is, it should have some surprises for everyone.

Read more

The original research: The changing face of cognitive gender differences in Europe

My previous column on gender differences: Are men better wired to read maps or is it a tired cliché?

Cordelia Fine’s book, Delusions of gender: how our minds, society, and neuro-sexism create difference

The Conversation

This article was originally published on The Conversation.
Read the original article.

Shuffle Your Mind: Short Film Screenings

If you’re around in London Saturday 2nd August I’m curating a showing of short films about psychosis, hallucinations and mental health as part of the fantastic Shuffle Festival.

The films include everything from a first-person view of voice hearing, to out-of-step behaviour in the urban sprawl, to a free-diver’s deep sea hallucinations.

There will be a discussion after the showing with film-makers and first-person visionaries about the challenges of depicting altered minds, other inner worlds and the limits of mental health.

Tickets are free but you have to book as there are only 40 seats.

If you want to join us, find the event on this page (which doesn’t list all the films, so prepare for some surprises) and click to book.

Seeing ourselves through the eyes of the machine

I’ve got an article in The Observer about how our inventions have profoundly shaped how we view ourselves because we’ve traditionally looked to technology for metaphors of human nature.

We tend to think that we understand ourselves and then create technologies to take advantage of that new knowledge but it usually happens the other way round – we invent something new and then use that as a metaphor to explain the mind and brain.

As history has moved on, the mind has been variously explained in terms of a wax tablets, a house with many rooms, pressures and fluids, phonograph recordings, telegraph signalling, and computing.

The idea that these are metaphors sometimes gets lost which, in some ways, is quite worrying.

It could be that we’ve reached “the end of history” as far as neuroscience goes and that everything we’ll ever say about the brain will be based on our current “brain as calculation” metaphors. But if this is not the case, there is a danger that we’ll sideline aspects of human nature that don’t easily fit the concept. Our subjective experience, emotions and the constantly varying awareness of our own minds have traditionally been much harder to understand as forms of “information processing”. Importantly, these aspects of mental life are exactly where things tend to go awry in mental illness, and it may be that our main approach for understanding the mind and brain is insufficient for tackling problems such as depression and psychosis. It could be we simply need more time with our current concepts, but history might show us that our destiny lies in another metaphor, perhaps from a future technology.

I mention Douwe Draaisma’s book Metaphors of Memory in the article but I also really recommend Alison Winter’s book Memory: Fragments of a Modern History which also covers the fascinating interaction between technological developments and how we understand ourselves.

You can read my full article at the link below.

Link to article in The Observer.

Awaiting a theory of neural weather

In a recent New York Times editorial, psychologist Gary Marcus noted that neuroscience is still awaiting a ‘bridging’ theory that elegantly connects neuroscience with psychology.

This reflects a common belief in cognitive science that there is a ‘missing law’ to be discovered that will tell us how mind and brain are linked – but it is quite possible there just isn’t one to be discovered.

Marcus, not arguing for the theory himself, describes it when he writes:

What we are really looking for is a bridge, some way of connecting two separate scientific languages — those of neuroscience and psychology.

Such bridges don’t come easily or often, maybe once in a generation, but when they do arrive, they can change everything. An example is the discovery of DNA, which allowed us to understand how genetic information could be represented and replicated in a physical structure. In one stroke, this bridge transformed biology from a mystery — in which the physical basis of life was almost entirely unknown — into a tractable if challenging set of problems, such as sequencing genes, working out the proteins that they encode and discerning the circumstances that govern their distribution in the body.

Neuroscience awaits a similar breakthrough. We know that there must be some lawful relation between assemblies of neurons and the elements of thought, but we are currently at a loss to describe those laws.

The idea of a DNA-like missing component that will allow us to connect theories of psychology and neuroscience is an attractive one, but it is equally as likely that the connection between mind and brain is more like the relationship between molecular interactions and the weather.

In this case, there is no ‘special theory’ that connects weather to molecules because different atmospheric phenomena are understood in multiple ways and across multiple models, each of which has a differing relationship to the scale at which the physical data is understood – fluid flows, as statistical models, atomic interactions and so on.

In explanatory terms, ‘psychology’ is probably a lot like the weather. The idea of their being a ‘psychological level’ is a human concept and its conceptual components won’t neatly relate to neural function in a uniform way.

Some functions will have much more direct relationships – like basic sensory information and its representation in the brain’s ‘sensotopic maps’. A good example might be how visual information in space is represented in an equivalent retinotopic map in the brain.

Other functions will have more more indirect relationships but in great part because of how we define ‘functions’. Some have very empirical definitions – take iconic memory – whereas others will be cultural or folk concepts – think vicarious embarrassment or nostalgia.

So it’s unlikely we’re going to find an all-purpose theoretical bridge to connect psychology and neuroscience. Instead, we’ll probably end up with what Kenneth Kendler calls ‘patchy reductionism’ – making pragmatic links between mind and brain where possible using a variety of theories and descriptions.

A search for a general ‘bridging theory’ may be a fruitless one.

Link to NYT piece ‘The Trouble With Brain Science’.

Out on a limb too many

Two neuropsychologists have written a fascinating review article about the desire to amputate a perfectly healthy limb known variously as apotemnophilia, xenomelia or body integrity identity disorder

The article is published in the Journal of Neuropsychiatric Disease and Treatment although some who have these desires would probably disagree that it is a disease or disorder and are more likely to compare it to something akin to being transgender.

The article also discusses the two main themes in the research literature: an association with sexual fetish for limb aputation (most associated with the use of the name apotemnophilia) and an alteration in body image linked to differences in the function of the parietal lobe in the brain (most associated with the use of the name xenomelia).

It’s a fascinating review of what we know about this under-recognised form of human experience but it also has an interesting snippet about how this desire first came to light not in the scientific literature, but in the letters page of Penthouse magazine:

A first description of this condition traces back to a series of letters published in 1972 in the magazine Penthouse. These letters were from erotically-obsessed persons who wanted to become amputees themselves. However, the first scientific report of this desire only appeared in 1977: Money et al described two cases who had intense desire toward amputation of a healthy limb. Another milestone was a 2005 study by Michael First, an American psychiatrist, who published the first systematic attempt to describe individuals who desire amputation of a healthy limb. Thanks to this survey, which included 52 volunteers, a number of key features of the condition are identified: gender prevalence (most individuals are men), side preference (left-sided amputations are most frequently desired), and finally, a preference toward amputation of the leg versus the arm.

The review also discusses a potentially related experience which has recently been reported – the desire to be paralysed.

If you want a more journalistic account, Matter published an extensive piece on the condition last year.

Link to scientific review article on apotemnophilia / xenomelia.
Link to Matter article.

Towards a scientifically unified therapy

nature_scienceToday’s edition of Nature has an excellent article on the need to apply cognitive science to understanding how psychological therapies work.

Psychological therapies are often called ‘talking treatments’ but this is often a misleading name. Talking is essential, but it’s not where most of the change happens.

Like seeing a personal trainer in the gym, communication is key, but it’s the exercise which accounts for the changes.

In the same way, psychological therapy is only as effective as the experience of putting changes into practice, but we still know relatively little about the cognitive science behind this process.

Unfortunately, there is a traditional but unhelpful divide in psychology where some don’t see any sort of emotional problem as biological in any way, and the contrasting divide in psychiatry where biology is considered the only explanation in town.

The article in Nature argues that this is pointless and counter-productive:

It is time to use science to advance the psychological, not just the pharmaceutical, treatment of those with mental-health problems. Great strides can and must be made by focusing on concerns that are common to fields from psychology, psychiatry and pharmacology to genetics and molecular biology, neurology, neuroscience, cognitive and social sciences, computer science, and mathematics. Molecular and theoretical scientists need to engage with the challenges that face the clinical scientists who develop and deliver psychological treatments, and who evaluate their outcomes. And clinicians need to get involved in experimental science. Patients, mental-health-care providers and researchers of all stripes stand to benefit.

The piece tackles many good examples of why this is the case and sets out three steps for bridging the divide.

Essential reading.

Link to ‘Psychological treatments: A call for mental-health science’.

Why do we bite our nails?

It can ruin the appearance of your hands, could be unhygienic and can hurt if you take it too far. So why do people do it? Biter Tom Stafford investigates

What do ex-British prime minster Gordon Brown, Jackie Onassis, Britney Spears and I all have in common? We all are (or were) nail biters.

It’s not a habit I’m proud of. It’s pretty disgusting for other people to watch, ruins the appearance of my hands, is probably unhygienic and sometimes hurts if I take it too far. I’ve tried to quit many times, but have never managed to keep it up.

Lately I’ve been wondering what makes someone an inveterate nail-biter like me. Are we weaker willed? More neurotic? Hungrier? Perhaps, somewhere in the annals of psychological research there could be an answer to my question, and maybe even hints about how to cure myself of this unsavoury habit.

My first dip into the literature shows up the medical name for excessive nail biting: ‘onychophagia’. Psychiatrists classify it as an impulse control problem, alongside things like obsessive compulsive disorder. But this is for extreme cases, where psychiatric help is beneficial, as with other excessive grooming habits like skin picking or hair pulling. I’m not at that stage, falling instead among the majority of nail biters who carry on the habit without serious side effects. Up to 45% of teenagers bite their nails, for example; teenagers may be a handful but you wouldn’t argue that nearly half of them need medical intervention. I want to understand the ‘subclinical’ side of the phenomenon – nail biting that isn’t a major problem, but still enough of an issue for me to want to be rid of it.

It’s mother’s fault

Psychotherapists have had some theories about nail biting, of course. Sigmund Freud blamed it on arrested psycho-sexual development, at the oral stage (of course). Typical to Freudian theories, oral fixation is linked to myriad causes, such as under-feeding or over-feeding, breast-feeding too long, or problematic relationship with your mother. It also has a grab-bag of resulting symptoms: nail biting, of course, but also a sarcastic personality, smoking, alcoholism and love of oral sex. Other therapists have suggested nail-biting may be due to inward hostility – it is a form of self-mutilation after all – or nervous anxiety.

Like most psychodynamic theories these explanations could be true, but there’s no particular reason to believe they should be true. Most importantly for me, they don’t have any strong suggestions on how to cure myself of the habit. I’ve kind of missed the boat as far as extent of breast-feeding goes, and I bite my nails even when I’m at my most relaxed, so there doesn’t seem to be an easy fix there either. Needless to say, there’s no evidence that treatments based on these theories have any special success.

Unfortunately, after these speculations, the trail goes cold. A search of a scientific literature reveals only a handful of studies on treatment of nail-biting. One reports that any treatment which made people more aware of the habit seemed to help, but beyond that there is little evidence to report on the habit. Indeed, several of the few articles on nail-biting open by commenting on the surprising lack of literature on the topic.

Creature of habit

Given this lack of prior scientific treatment, I feel free to speculate for myself. So, here is my theory on why people bite their nails, and how to treat it.

Let’s call it the ‘anti-theory’ theory. I propose that there is no special cause of nail biting – not breastfeeding, chronic anxiety or a lack of motherly love. The advantage of this move is that we don’t need to find a particular connection between me, Gordon, Jackie and Britney. Rather, I suggest, nail biting is just the result of a number of factors which – due to random variation – combine in some people to create a bad habit.

First off, there is the fact that putting your fingers in your mouth is an easy thing to do. It is one of the basic functions for feeding and grooming, and so it is controlled by some pretty fundamental brain circuitry, meaning it can quickly develop into an automatic reaction. Added to this, there is a ‘tidying up’ element to nail biting – keeping them short – which means in the short term at least it can be pleasurable, even if the bigger picture is that you end up tearing your fingers to shreds. This reward element, combined with the ease with which the behaviour can be carried out, means that it is easy for a habit to develop; apart from touching yourself in the genitals it is hard to think of a more immediate way to give yourself a small moment of pleasure, and biting your nails has the advantage of being OK at school. Once established, the habit can become routine – there are many situations in everyone’s daily life where you have both your hands and your mouth available to use.

Understanding nail-biting as a habit has a bleak message for a cure, unfortunately, since we know how hard bad habits can be to break. Most people, at least once per day, will lose concentration on not biting their nails.

Nail-biting, in my view, isn’t some revealing personality characteristic, nor a maladaptive echo of some useful evolutionary behaviour. It is the product of the shape of our bodies, how hand-to-mouth behaviour is built into (and rewarded in) our brains and the psychology of habit.

And, yes, I did bite my nails while writing this column. Sometimes even a good theory doesn’t help.


This was my BBC Future column from last week