How evolution (doesn't) work

Last night my son and I were discussing the fact that, in general, women seem to sleep more lightly than men and speculating that this might be an evolutionary development because women need to wake during the night to care for a baby. Max wondered whether that will change in the future, now that men – in some cases – take more responsibility for night-time child care (although biologically they still can't do all of it).

This led to a discussion about evolution, and how adaptations aren't necessarily the best possible way of dealing with a situation, but only the most successful way of surviving. And here's a case in point:

An article in Scientific American reports that researchers have found a protein in the brains of mice that inhibits long-term memory formation. This protein is also, apparently, found in humans. The researchers knocked out the gene for the protein in some mice and found that the knockout mice were smarter than their normal peers. (Sound familiar?) Note that the researchers are not sure about any possible negative side effects of knocking out this protein yet, so Charlie is still working in the bakery for now.

This raises a question: why would we evolve to produce a protein in our brain that makes us dumber? The answer is that evolution happens more or less at random, not with any intention to design the best possible human being. Of course, being smarter would be better for our survival, but being as smart as we are has worked well enough to be successful. Until now.

Algernon and Charlie's (fictional) experience notwithstanding, my next question is, where do I sign up to knock out my dumbing-down genes? As I get older, I need all the help with my memory that I can get.