The human brain is still evolving
Scientists have discovered that the human brain is still evolving. By comparing modern man to his ancestors of 37,000 years ago — a blink of the eye in evolutionary timescales — researchers have discovered two genes linked to brain size. One of the new genes emerged only 5,800(!) years ago, and is only present in 30% of human beings. These very short timeframes suggest intense selection pressures.
What’s more interesting is that these two gene variants arose right around the time that cultural behavior developed. It appeared alongside other things like art, music, and sophisticated religious practices and tools.
The researchers caution that the two genes are linked to increased brain size, but not necessarily greater intelligence. I would speculate that they are but a small piece in the evolving of the modern human brain. Consider that Neanderthals were better physically suited to a harsh environment, but that Homo sapiens outlasted Neanderthals and became the dominant species on Earth. Neanderthals had no speech or written language, whereas their bigger-brained Homo sapiens cousins did. Perhaps these two genes are but one part of a larger evolutionary picture that we are just now discovering.
I have written in the past about the difference between genes and memes, and the human social structure. It is thought that these evolutionary changes conferred to us some greater ability to survive (such is the nature of natural selection). But natural selection doesn’t have to be limited to purely physical pressures. Societal pressures can nudge natural selection along a given path by allowing those with greater societal savvy (for lack of a better term) to procreate more. As humans became more community based and interdependent on one another, the ability to interact socially as a means of reproducing becomes valuable. In essence, genes serve the overarching meme, which is complex interdependence and economics.
The most exciting aspect of this discovery is that it means that the human brain is still evolving today, and that humans a long time from now will probably have different brains and capabilities than we do today.
Of course, the real question everyone wants to know the answer to is… How long before we can beat a cashier senseless so we can steal a candy bar… without lifting a finger?
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…Neanderthals had no speech or written language, whereas their bigger-brained Homo sapiens cousins did…
Rian, you seem quite content to hit off the inaccuracies (such as claiming a 990cc brain in your florensis post) which even a few seconds on the likes of Wikipedia would fix.
Neandertalensis had extensive language, clearly evidenced by a Broca’s region of Sapiens size (That’s the brain area responsible for language, it evolved with H.Habilis) and had a larger brain than Sapiens, but was of the same intellect due to a larger body also, the same way that a blue whale has a brain bigger than some Japanese apartments but doesn’t go around building rockets. Note also that Sapiens has been around 350,000 years at least. We’ve had written language for 8,000 of those, or for 2.3% of our history – It’s a very recent invention.
The reason for Neandertalensis’ extinction was thier lack of habitat. They’d evolved to handle the European ice age and when it went interglacial, their niché wasn’t there anymore and to make it worse, Sapiens moved in who didn’t carry the same evolutionary baggage.
Neandertalensis’ other disadvantage is that he was a literal thinker. The brain areas which cope with abstract thought were quite weak in Neandertalensis, hadn’t changed much from Erectus. That’s precisely what you need for day-to-day survival in an environment out to kill you, the ability to make inventions which solve your problems. Distractions like making inventions for which you don’t yet have a problem (i.e. the Wright brothers) were just that, distractions.
So while Neandertalensis would have out-competed Sapiens in a harsh and hostile environment, he wasn’t capable of the kind of thought which results in him mastering his environment, he was very much mastered by it.
While I’m here (and hominid evolution is a pet topic of mine) there’s a bit of evidence suggesting Neandertalensis lived alongside Sapiens for quite some time and is remembered in folk memory.[1]
Most cultures have tales of giants, they’re even in the Old Testament as “Nephilim” if I have the name right. If we go back 15,000 years, we reach a semi-agrarian state of society where people were mostly malnourished and the superior physique of Neandertalensis would have thrived in such a scenario. The five foot tall Sapiens would have been dwarfed by Neandertalensis, especially in musclature. Twist the story a bit over the centuries, you have tales of giants.
It’s not unreasonable to expect pockets of Neandertalensis to have survived until that recently, they were just as well kitted for most sorts of survival as we were.
[1] There’s unrelated evidence of folk memory stretching back an easy 6,000 years and remaining pretty much intact. (http://www.meteoritemarket.com/CCinfo.htm) Stones falling from heaven 6,000 years ago according to folklore, we now find the meteorite field. Take it another 6,000 years and the stones were handed to man by the gods.
Comment by Wayne H — October 9, 2005 @ 12:19 am