Yesterday was the 200th anniversary of Charles Darwin's birth, and the mainstream media was filled with the obligatory slew of evolutionary pieces. Read one article claiming that religious people tend to have more children than 'free-thinking' folk, and so (since most people stick with the religion they're born into) in a hundred years religious zealots will make up an overwhelming majority of the global population. Good luck future generations!
This got me thinking about what selective pressures may currently be at work on humans. In the developed world, modern man lives free of want and can successfuly combat infectious disease. In short, we are guaranteed survival - at least till reproductive age, which is all that matters for evolutionary purposes. The welfare state, as Richard Dawkins pointed out, is not a Darwinian arena. So is anything being selected for? What traits would proliferate in such an environment?
How about genes that modulate one's temperament [Such genes do exist; check out this article on a variant associated with optimism: http://www.economist.com/science/displaystory.cfm?story_id=13176767] An increasingly unchallenging lifestyle has given us so much idle time that perhaps even a slightly morose disposition can sink a mind into a deep depression. In their despair, these people may not live long enough to reproduce, or they may decide against bringing another life into such a miserable world. Perhaps, then, variation that promotes a sense of joie de vivre might proliferate in the human population. Positive selection for genes that encode happiness!
Now, one could argue that variants that make humans suicidal would be eliminated regardless of the environment, and such selection would have been happening since the origin of our species. That may be true; all I'm saying is that our modern lifestyle may amplify the effects of depression. Someone struggling to survive while living a hunter-gatherer existence does not have the time to ponder, get disillusioned and depressed; whereas in Bruges, time is by no means in short supply!
An important caveat is that I've neglected the impact of antidepressant drugs, which would counter negative selection against depression. Although, if the drugs really are effective, our species will find happiness one way or another - via natural selection or human intervention!
I'm trying to understand where you're going with this...but I can't. I'm probably just not as smart as you, but then again I just worked an 11 hour day so I don't need to be.
ReplyDeleteBy the way, your email about India was superb. I would turn that into a blog story. You must take me there one day.
Is it possible to attribute the % of a being's optimistism/negativism personality(however it is defined)that is inherited vs learned through cultural/social development in quantitative terms? I would think optimism is unique to each individual's genes and social circumstances? I think another interesting study would be to conduct within large families; 20 kids with same parents and to compare the kids' personalities.
ReplyDeleteHave you seen the suicidal rates vs reproduction rates overtime across countries? Suicidal rates are lower in religious nations..but are we as a global nation trending towards or away from devout religion? Do you think we can get to a point where we have more suicides/early deaths than repoduction, ultimately shrinking our population. That would be interesting.
To the extent our optimism is coded in our genes, can we modify our genetic code permanently; i.e, effectively stabilizing serotonin levels in humans. I suppose to some extent those are the temporary functions of anti-depressings. We could chemically alter humans to be super optimistic or super pessimistic forever...