Skeptics in the Pub June 2015

Professor Sophie Scott comes to The Canalhouse to talk to Nottingham Skeptics in the Pub about getting brain sex wrong.

The timing is perfect, coming in the same week that Nobel laureate Tim Hunt claimed that “girls” shouldn’t work in labs. He claimed that “three things happen when they are in a lab; you fall in love with them, they fall in love with you and when you criticize them, they cry”

This clearly feeds into the beginning of the talk where Sophie asks, “what is normal?” How is “normal” defined by our cultural expectations and our social knowledge?

First up, some questions on stereotypes:

1. Who talks more? Men or women?
2. Who plays more computer games? Men or women?
3. Who is more aroused be erotic stimuli? Men or women?
4. Who gossips more? Men or women?
5. Is it more expensive to raise a boy or a girl?

1) Men 2) Women 3) Women 4) Same 5) Boys are 20% more expensive

All of which brings us onto brain sex theory. Those who believe in it say that since the embryo is effected at different stages by exposure to hormones, then this must also effect the brain. Surely those same hormones have an impact on brain structure and brain function. Well, it actually turns out that men’s brains are larger than women’s brains but women’s brains contain more grey matter (the brain’s processing power)

However, there are differences in behaviour between men and women. For example men perform better at spatial tasks while women perform better at language-based ones. Having said that, you need large populations before you can see these differences. There is also more variation within either population than there is between them.

So there are more differences among the men then there are between the men and women. Of course there can’t be complete differentiation due to our genetic make-up.

But why are there differences? Are our brains different? Or is it just down to different experiences? If brain sex theory is correct then the differences should rest in brain differences. So, maybe women are differently lateralised for language. However, language usually derives in the left hemisphere, even for left-handed people.

In fact there is very little difference in lateralisation between men and women. Research shows that age and reading strategy are the most prominent sources of difference in ability for reading familiar words aloud.

If there was a difference in lateralisation, you might expect there to be a difference following brain damage but women do not recover better from strokes than men. This is the case even if you look at post-stroke language tasks. In fact, due to women having lower haemoglobin levels, women are more adversely effected by strokes.

Recent research, which even made it as far as a BBC documentary, showed that women have more cross-hemisphere connections in their brains while men’s connections are more in the same hemisphere. This was announced with great fanfare as proof that women are better at multi-tasking than men. However, there is no behavioural data showing differences between men and women when it comes to multi-tasking. In fact the research was carried out on just 11 people (6 men and 5 women)

However, there are people who do have different brains – phoneticians. It turns out that an MRI can find differences in the brains of those people who can speak multiple languages compared to those who cannot. But what are the developmental effects that have caused this? Is it similar to Katie Alcock’s research in Tanzania where she showed that locals have improved spatial memory?

Back to the differences between men and women – why are there so few women in computer science. Only 18% of undergraduates are female. Up until the mid-1980’s the numbers were increasing year-on-year until they suddenly fell off a cliff. This coincides with the explosion of home computing. It seems that once they were available in the home, they were seen as things for boys rather than girls.

We also see a huge discrepancy in the UK prison population. There are less than 10,000 women in prison against over 80,000 men. Is this purely because they’re men? Is it because women can’t commit crime?

Even Nigel Short, the English chess grandmaster has weighed in on the gender debate, claiming that women can’t paly chess. The thing is, neither can most men.

This all leads back to idea of what society considers to be “normal” behaviour. Men with computers, men in jail, women not playing chess are all considered to be normal these days. However, you only need to go back to the 1960s to see behaviour that would have gotten you committed back then, is now considered to be completely normal.

Finally, Sophie talks about gay sheep. Around 10% of adult male sheep are gay and this can have financial implications for farmers, hence there has been quite a lot of research into it (although there hasn’t been any research into female sheep) People have been comparing the brains of sheep to see if there are any differences that may drive sexuality.

Well, it turns out that straight male sheep have a larger anterior hypothalamus than female sheep. Gay male sheep have a smaller one than straight male sheep. So, do this mean that gay male sheep have a brain that is more similar to female sheep? No – actually, gay male sheep behave differently to female sheep. So, the research has to continue since only around 50% of males sheep are actually straight (yes, you can get bisexual and asexual sheep)

During an excellent Q and A session, Sophie re-iterates the fact that experience is a much larger driver in the differences in brains than gender is. Our brains are the same as early mankind who were able to spread out across the globe and survive. It’s such a flexible organ that it would make no sense for it to be different in men and women.

There’s also some more debunking – there are not more autistic men than autistic women. Similarly, autistic women are not more likely to be similar to non-autistic men.

However, there is one final societal change that we have seen over the last 40 years and it’s nothing to do with brain sex theory – the pitches of women’s voices has lowered since they became more active in the workplace alongside men. Maybe they just want to fit in with Tim Hunt…

Nottingham Skeptics in the Pub will return on 7th of July at 7:30 in The Canalhouse where Michael Marshall will be talking about Homeopathy in the UK

Author’s notes

Article not previously published

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