Humans evolving into hyper-intelligent beings is a powerful idea in science fiction, but that's probably where the idea will have to stay. Our brains have reached an evolutionary "sweet spot", and we can't get much smarter without making major trade-offs.
That's the finding of psychologists Thomas Hills of the University of Warwick and Ralph Hertwig of the University of Basel. They have examined a number of studies, and they have come to one inescapable conclusion: there's a steep price to pay for enhanced brainpower, and it's almost certainly not a good deal from an evolutionary perspective.
They point to how groups of people with enhanced cognitive abilities - including "savants, people with photographic memories, and even genetically segregated populations of individuals with above average IQ" - and these groups generally suffer from much higher rates of cognitive disorders like autism, extreme synesthesia, and other neural disorders. The researchers also point to attention-focusing drugs like Ritalin, which can really help people with ADD but can actually decrease performance when taken by people with normal attention spans.
Dr. Hillis explains their conclusions:
"These kinds of studies suggest there is an upper limit to how much people can or should improve their mental functions like attention, memory or intelligence. Take a complex task like driving, where the mind needs to be dynamically focused, attending to the right things such as the road ahead and other road users — which are changing all the time. If you enhance your ability to focus too much, and end up over-focusing on specific details, like the driver trying to hide in your blind spot, then you may fail to see another driver suddenly veering into your lane from the other direction.
"Or if you drink coffee to make yourself more alert, the trade-off is that it is likely to increase your anxiety levels and lose your fine motor control. There are always trade-offs. In other words, there is a 'sweet spot' in terms of enhancing our mental abilities — if you go beyond that spot — just like in the fairy-tales — you have to pay the price."
Of course, this still leaves open the possibility that a more radical adaptation could open the way to dramatically increased intelligence - although what exactly that would be is anybody's guess - but it does appear that we've reached the limits of incremental intelligence growth.