Multi-tasking in the stone-age

Stone blades found in Sibudu Cave, near South Africa’s Indian Ocean coast, bear traces of compound adhesives that once joined them to wooden hafts to make spears or arrows.

Why is this so cool? Because by systematically replicating the ancient glues, using only Stone Age techniques and ingredients, the researchers discovered that ocher improves the bonding capacity of such natural adhesives as acacia gum. They also learned that those ingredients are highly variable in chemical composition and thus in key characteristics, such as viscosity, that affect the strength of the bond.

To make an effective glue, say the researchers, ancient artisans would have had to adjust their recipes in real time to compensate for unpredictable ingredients, staying mindful of their goal while shifting their focus back and forth among the various steps in the process.

So maybe they were just mad scientists! Mwahahaha!

Gender in the brain

Scientific American recently published an article suggesting that boy brains and girl brains were not as biologically different as one might think.

Excerpt: "At first glance, studies of the brain seem to offer a way out of this age-old nature/nurture dilemma. Any difference in the structure or activation of male and female brains is indisputably biological. However, the assumption that such differences are also innate or “hardwired” is invalid, given all we’ve learned about the plasticity, or malleability of the brain. Simply put, experiences change our brains....

"...[For example] If the sex difference in the straight gyrus (SG) is present early in life, this strengthens the idea that it is innately programmed. Wood and Nopoulos therefore conducted a second study with colleague Vesna Murko, in which they measured the same frontal lobe areas in children between 7 and 17 years of age. But here the results were most unexpected: they found that the SG is actually larger in boys ! What’s more, the same test of interpersonal awareness showed that skill in this area correlated with smaller SG, not larger, as in adults."

Here is Rafe's response to the article:

This article is terribly written, with ridiculous assumptions.

The first one - "On the other hand, sex differences that grow larger through childhood are likely shaped by social learning, a consequence of the very different lifestyle, culture and training that boys and girls experience in every human society."

This is patently ridiculous. Virtually all sex differences grow larger with age as males and females diverge hormonally. Obviously we wouldn't use culture to explain the accelerating gap in height and mass, or bone structure or secondary sex characteristics. Even gaps in things like aggression and neuroticism increase with age to peak in the early twenties before coming more in line with each other as we age beyond the 20's.

Secondly, "Individuals’ gender traits—their preference for masculine or feminine clothes, careers, hobbies and interpersonal styles—are inevitably shaped more by rearing and experience than is their biological sex."

This is just wishfull thinking. There is no experimental evidence to support this; essentially we are just talking about two sides of the same coin the masculinity or feminity of the body vs. the mind. Both are largely genetic, we just don't fully understand all the mechanisms.

It pisses me off that they have to frame every story about this like somehow culture is the good guy riding in, that we can't write it off, it might just save us from the big bad genetic bad guys after all. It's editorializing and literally twisting the actually meaning of the study backwards, the important lesson of that study is yet another consistent and persistent cognitive difference between the sexes but they try to make it seem ok by implying it really all might be cultural.