[Eclipse] Gender and Social Class

[Jason Lee]

Well, you seem to know where you're going, I just wanted to touch briefly on your reply.

As for the Agility thing, given that we both agree on the flexibility issue, the question becomes:  How important is flexibility compared to strength/structural stability in regards to the tasks of dodging, jumping, climbing, gymnastics, and acrobatics?  (I love the layout, BTW).  I would definitely say it is important, but of significantly less importance than other things.  From my perspective, flexibility does not equal to Agility as you have it defined.

...but white matter/grey matter means absolutely nothing when it comes to verbal and spatial tasks. This "finding" means didly squat except that information is processed faster in a male brain than in a female brain, and that more complicated processing can occur in a female brain than in a male brain. The reason females perform better at verbal tasks has nothing to do with white matter/grey matter, it has everything to do with the left hemisphere bias and overall lower degree of lateralization in a female brain. The reason men perform better in spatial tasks has everything to do with the strong right hemisphere dominance and strong lateralization of the brain.

They are paraphrasing, because the list is supposed to be easy to read.  Their source is:

Gur RC, Turetsky BI, Matsui M, et al. Sex differences in brain gray and white matter in healthy young adults: correlations with cognitive performance. J Neurosci. 1999;19(10):4065-4072.

The paper is readily available online, the following is an excerpt (most of the paper is too dense for me to follow, but this is somewhat readable).

Sex-related differences in behavior are extensive, but their neuroanatomic substrate is unclear. Indirect perfusion data have suggested a higher percentage of gray matter (GM) in left hemisphere cortex and in women, but differences in volumes of the major cranial compartments have not been examined for the entire brain in association with cognitive performance. We used volumetric segmentation of dual echo (proton density and T2-weighted) magnetic resonance imaging (MRI) scans in healthy volunteers (40 men, 40 women) age 18-45. Supertentorial volume was segmented into GM, white matter (WM), and CSF. We confirmed that women have a higher percentage of GM, whereas men have a higher percentage of WM and of CSF. These differences sustained a correction for total intracranial volume. In men the slope of the relation between cranial volume and GM paralleled that for WM, whereas in women the increase in WM as a function of cranial volume was at a lower rate. In men the percentage of GM was higher in the left hemisphere, the percentage of WM was symmetric, and the percentage of CSF was higher in the right. Women showed no asymmetries. Both GM and WM volumes correlated moderately with global, verbal, and spatial performance across groups. However, the regression of cognitive performance and WM volume was significantly steeper in women. Because GM consists of the somatodendritic tissue of neurons whereas WM comprises myelinated connecting axons, the higher percentage of GM makes more tissue available for computation relative to transfer across distant regions. This could compensate for smaller intracranial space in women. Sex difference in the percentage and asymmetry of the principal cranial tissue volumes may contribute to differences in cognitive functioning.

[snip, until page 6]

For the verbal task, in which the overall correlation between parenchymal volume and performance is low, the higher percentage of GM in women and the steeper slope of improved performance with increased WM combine to confer on women a performance advantage. However, as seen from the association between WM volume and performance on the spatial tasks, men may perform better on tasks in which a high level of performance requires large volumes of WM. This suggests that verbal tasks require less intrahemispheric transfer than spatial tasks and that sex differences in performance would depend on the relative requirements for GM and WM. However, these correlations could be spurious and should be interpreted with extreme caution. Testing this hypothesis would require a wider range of tasks showing sex differences in performance and perhaps constructing new tasks designed to require either highly focal processing or transfer of information across distant cortical regions.

Heh.  I didn't think anyone would challenge the credibility of the Society for Women's Health Research.  No matter, all research does not agree - they have theirs and you have yours.  There is sufficient data to support the Spatial/Verbal distinction, which is the point I was trying to make.  Logic, analysis, learning, and memory are all dependent upon the task.  Math is spatial, hence the average male tends to find analysis and memory in these areas easier; while women have an easier time with foreign languages.  I don't think you're looking at a distinction of 'who is more logical and remembers better', but instead 'how they are logical and what they remember'.  I was recently called on my own oversimplification of the left/right brain distinction by Eero and Markus.  Women have been shown to be better at remembering faces, which is a spatial task.  So, it's all sorts of complicated.

Anyway, not trying to beat a dead horse.  Just clarifying my position.  I'm not really too interested in the niggling details of this or even trying too hard to persuade you, because we'll just get ourselves into the realm of inconclusive data, and hence nowhere.  I'm just looking at it from within your own requirements, and these are the discrepancies I see.