A
fascinating paper about sex differences in the human brain was published last week in the scientific journal
Cerebral Cortex. It's the largest single-sample study of structural and functional sex differences in the human brain ever undertaken, involving over 5,000 participants (2,466 male and 2,750 female). The study has been attracting attention for more than a year (see
this preview in Science, for instance), but only now has it been published in a peer-reviewed journal.
For those who believe that gender is a social construct, and there are no differences between men and women's brains, this paper is something of a reality check. The team of researchers from Edinburgh University, led by Stuart Ritchie, author of
Intelligence: All That Matters, found that men's brains are generally larger in volume and surface area, while women's brains, on average, have thicker cortices. '
The differences were substantial: in some cases, such as total brain volume, more than a standard deviation,' they write. This is not a new finding - it has been known for some time that the total volume of men's brains is, in general, larger than that of women's, even when adjusted for men's larger average body size - but all the studies before now have involved much smaller sample sizes.
Does this paper have any implications when it comes to men and women's intellectual abilities? The answer is yes, but they're not clear cut.
On the one hand, feminists won't like this confirmation that men, on average, have bigger brains than women because there's a well-established connection between total brain volume and IQ. That was the conclusion of the authors of a
2015 meta-analysis that looked at 88 studies involving 148 mixed sex samples comparing magnetic resonance images of people's brains with their cognitive test scores. They found that the
association between brain volume and cognitive ability was positive in children and adults, applied across a range of different IQ domains (full-scale, performance and verbal IQ) and was true of both men and women. According to
another study led by Richard Haier, author of
The Neuroscience of Intelligence, total brain volume accounts for about 16 per cent of the variance in IQ.
Comment: And with increasingly brutal winters and extreme weather events the similarities to the Maunder Minimum, and other periods of low solar activity, are worryingly apparent. Some observers are also noticing that its not just the sun exhibiting unusual behaviour:
- Yale's Two Climate Bombs Point to Impending Ice Age
- Strange behavior coming from the sun's gamma rays, cause unknown
- Solar minimum: The sun is getting quieter... and its rotation is slowing down
- Revision to 400-year sunspot record makes current solar cycle weakest in 200 years
- Massive flooding in Europe during the Little Ice Age
- Erratic seasons and extreme weather devastating crops around the world
Also check out SOTT radio's: Behind the Headlines: Earth changes in an electric universe: Is climate change really man-made?And our monthly documentary: SOTT Earth Changes Summary - April 2018: Extreme Weather, Planetary Upheaval, Meteor Fireballs