Are Humans Done Evolving?

In an interview on the Philosopher's Zone, I heard the following dialog:

Roy Williams: … all species that have ever lived on earth, except for man, have not been able to discover the laws of physics that underlie everything.

Alan Saunders: Well they know as much as they need to.

Roy Williams: That's exactly the point… You don't need that ability to survive as a species on earth, therefore the fact that man alone of all creatures does understand the underlying laws that go back to the Year Dot, seems to me a fact of extraordinary significance… because in evolutionary terms it's quite unnecessary.

Are our brains necessary? Is big brains a complete mess up, or is high intelligence bound (or even possible) to happen through natural selection?

As my friend, Trent Tobler, once wrote me with an opinion on this subject:

One interesting proposal I have read is that our intellect is the peacock tail of humanity. The theory goes that male peacocks have this large, combersome, gaudy tail to advertise to potential mates that not only are they fit, but are so fit that they can even survive having the handicap of having this large, gaudy tail that certainly must attract a lot of predators and make it hard to fly -- and yet, here they are prancing around this very moment. So it could be with the human mind and 'belief'. The larger, gaudier, useless, and better, at odds with surviving would advertise a person's prowess at surviving in spite of the handicaps the beliefs provide must certainly be very appealing to a member of the opposite gender. It's an interesting theory, in any case.

I have another proposal… that intellect is an obvious progression. Think of a predator/prey situation, like Moose and Wolves. Moose are food for wolves, and by eating them, help to keep the moose population from growing too large (for if there are too many moose, they will eat everything and starve). But if the wolves eat too many moose, the resulting food shortage pares down their number, controlling their population, as well.

In other words, a balance is established. But by natural selection, many animals often starve. The squirrel caught by a hawk to feed its babies, means that the squirrel babies die of starvation. The hawk won't intend to, but if it eats too many parent squirrels, it won't have many squirrels to eat the following year. So the prey control the predator.

However, there was one predator, that started out being a hunter with many disadvantages, and compensated by using its ever increasing intellect. This intellect allowed the species to not be limited by its prey. It hunted the wild bison in Europe and Asia to extinction, but after putting them in pens, it could kill the adults this year, but also take care of the babies to kill the following year.

The species used it intellect to overcome the resource limitation to the point where the planet has billions of this one particular species, and without its culture, most of them would die quite quickly.

I previously talked about my ideas of why we evolved brains sufficiently large to become sentient, whereas the Troodons did not. Without terrible slashing claws and teeth to hunt, and without feathers to keep us warm, we'd have to compensate by evolving an ever-increasing brain size.

But I think we are done evolving as a single species.

Why? Well, in order for natural selection to occur, only the "most fit" should reproduce. In human societies, most have children. And with our technology, we can take care of humans that never would have survived a thousand years ago … or even 50.

I'm not suggesting we begin the practice of eugenics, far from it, but I do think that we will not evolve as a species. Species become two different species if they live in separate locations long enough, but humans travel and mate from various backgrounds… shuffling the genes back and forth in different individual patterns, but not in isolated gene pools. Well, except for maybe Kentucky.

While I don't think we are evolving biologically , I think we will evolve due to our technology. Right now, if you are born with a bad hip that would have made it impossible for you to climb up a tree before the smilodon caught you, we can, with a simple surgical procedure, fix that. Procedures like this, are paving the way for more and more integrations of our bodies with our technology.

But don't worry about it. Just like our grandparents didn't complain about eye glasses, and our parents didn't complain about contacts, and we are not complaining with laser eye surgery, neither will our children complain about the telescopic implants to allow us to finally see PowerPoint presentations in the meetings of the future.

I know what you are thinking… what about the dark side of science? Some people in the past, have justified their ethnic hatred and intolerance, by invoking the facts and theories of science. There are also lots of social issues that we need to grapple and wrestle as technology makes certain things possible.

For instance, it seems logical that we would want to use the exciting new field of gene therapy to cure genetic diseases. But of course, this will be abused with parents picking out their children's eye color. Is that a problem? The only way we will resolve these issues is by discussing them.

So, how shall we begin?

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It should probably be noted that evolution, and the idea of 'fitness' are not specific to the organism. It includes both the critter, and the environment. In the possible explanation of brain selection based on sexual selection, the fitness of a smart brain was proposed to be happening in an environment where lots of potential mates found smart brains attractive.

Imagine two other possible environments: a 'smart brain neutral' environment -- potential mates don't care one bit if your are smart or stupid, and a 'brain antagonistic' environment, where 'smart' is akin to having a contagious disease and bad breath (I.E, you repel mates with your smart brain).

Now, certainly, logically, the original environment would have a lot of positive pressures for getting a bigger brain. You would have all the positives and negatives for the smart neutral environment, but you would have all those potential mates fawning over you, and selecting you over your less brainy compatriots. Statistically, your going to have more (brainy) children than they are, and your children will tend to be more like you -- brainy and attracted to brainy.

In the second environment, there may still be some pressure to become brainy, but other factors in the environment are going to have a larger play. It also requires a lot more energy, which is not so good -- Instinct might be a better tactic than general 'smarts' depending on the environment and environmental change.

In the third environment, you're actually much worse off being smart (unless you can somehow trick or force those potential mates to bear your children that give you some kind of advantage over the stupid but insanely attractive competitors.)

Given the three possible environments, the first two are very likely to have happened, since, well, here we are, brainy and all. It seems to me that the first one would more certainly lead to our present state, and in point of fact, it seems to me that mentally challenged people have a bit harder time finding a potential mate (when compared with someone who has the brains, but all else equal.) I think it may go a little more beyond a simple "I'm smart and can figure out how to make myself attractive and can survive because I'm so smart" idea -- I think there still is some sexual bias to braininess.

In any case, on to your technological expansion. Again, selection and evolution involve both the organism (in this case, humans), and the environment (in your proposal, an environment where technology is freely available.) It makes sense to me that higher fitness would be achieved by individuals that make full use of the technology. However, they may actually become less fit in other environments (such as one where technology is NOT freely available). In my mind, there will always be some pressure to be a generalist (able to get by in many different environements), rather than a specialist (better than everyone else in one specific environment, but worse off in all others), simply because environmental change seems all but certain. The rate of this environmental change probably has a great bearing on how effective a more specialized strategy vs. a more generalized strategy makes sense.

The 'smart' genes may have been selected for via sexual selection, it may very well hit the lottery on being the ultimate generalist -- able to survive in many different environments by the ability to think thru and figure out how to survive in the new environments (either by adapting behavior to them [I.E, you pace yourself differently when treking across a swamp vs treking across a desert] -- or by changing and creating a localized environment more suitable to your survival [I.E, you build a house.]) The positive feedback forces created a cascading and self promoting evolution for being much smarter than the average chimp, even beyond the sexual selection that may have lit the fuse.

What are your thoughts?