Dec. 26, 2006 at 7:30 PM ET
Science-fiction tales often fast-forward the pace of evolution to create the big-brained humans of the future - or, for that matter, the big-brained chimps of "The Planet of the Apes." Research published this week in the journal PLoS Biology, however, argues that the more complex your brain gets, the harder it is to evolve further. The subject could have implications for speculation into the future of intelligence.
More than a year ago, we built that kind of speculation into our special report on "The Future of Evolution." Yes, we included a big-brained egghead as one of our options for future human evolution - even though the mere mechanics of having a huge head sitting on your typical human spine would be problematic, to say the least.
The argument against accelerated brain evolution laid out in PLOS Biology has more to do with genetics than mechanics: Researchers compared the pace of evolutionary change in humans and chimpanzees as well as macaque monkeys and mice - and they found that the brainier species exhibited a significantly slower rate of change in genes expressed exclusively in the brain.
"The more complex the brain, it seems, the more difficult it becomes for brain genes to change," the University of Chicago's Chung-I Wu said in a university news release. Why is that? The researchers speculate that with a system as complex as the human brain (or, for that matter, the chimp brain), a mutation is more likely to screw something up than to make it better.
Does that mean that we're pretty much stuck with the brains we have? Well, we can always use them more efficiently - and perhaps even augment them electronically. (Imagine a Bluetooth-enabled Google/Babelfish brain implant, for example.) Come to think of it, the same situation might hold for chimpanzees.
Over the years, scientists have gone back and forth on the genetic similarities between chimps and humans. Last year, geneticists determined that the two species' genomes were 96 percent identical - while last month, another research group said the earlier study overestimated the similarities somewhat.
Could the intelligence of other species be enhanced? Should humans help? Such were the questions I posed almost four years ago in an item titled "Chimp Encounters of the First Kind." Here's a follow-up, sent recently by a Cosmic Log correspondent named Jim:
"I believe higher intelligence is well-documented for those who don't presume otherwise.
"Check out the work done at the CHCI - the Chimpanzee Human Communication Institute at Central Washington University, in Ellensburg, Wash. There humans and half a dozen chimpanzees have been communicating via ASL American Sign Language for decades.
"It's not at all a question of 'if.' The students are researching subtle aspects and context details or somesuch (I'm not into the details). Meanwhile, in the ordinary process of daily caretaking, the staff regularly 'converse' with the chimps. One younger chimp was taught ASL, by the matriarch chimp, with no human intervention.
"I've heard anecdotal stories of interactions which indicate high levels of intelligence and awareness within the chimps. I'm sure this is much better documented in the professional literature from there."
I'm wondering what will happen when someone develops software to translate a chimp's ASL automatically into speech. Would more communication lead to brainier apes? Or are there genetic and neurological reasons for expecting that a chimp could say nothing more cogent than "give orange me give eat"? Feel free to add your observations or citations below.