Mean Genes

San Diego Union Tribune

October 1, 2000

In recent years, the debate over nature versus nurture has gone decidedly natural. Overweight? Blame it on your genes. Addicted to drugs? It's those damn genes. Prone to depression or infidelity? Again, genetics.

Of course, not everybody buys into this notion. The idea that biology substantially influences behavior is not just controversial, but unsettling. Does this mean people aren't responsible for their choices and actions?

Well, yes and no, say Terry Burnham and Jay Phelan, authors of "Mean Genes." Human behavior, they contend, is largely the result of natural selection. For example, we tend to fritter away our money -- spending lots, saving little -- because evolution suggests that's a better survival mode.

Our hunting and gathering ancestors typically consumed all they could as often and as quickly as they could. Saving for a rainy day made no sense because food (the most valuable commodity of the time) didn't last; it either spoiled or somebody else ate it. Thus, no gene for prudence -- food, fiscal or otherwise.

On the other hand, humans clearly aren't "dumb" animals. We have large brains, from which a novel state of consciousness and free will arise. Unlike other species, we spend great amounts of our time pondering – and anguishing -- over choices. A dog doesn't fret about weight control. It eats until it can eat no more. A chimp, as far as primatologists can tell, never resolves to be less selfish.

But humans do these two things and more. Thus, the book's subtitle: "Taming Our Primal Instincts." According to Burnham and Phelan, a genetic predisposition toward chubbiness doesn't dictate a lifetime of shopping at the Big & Tall or Pretty & Plump. But it does suggest you might benefit from a better understanding of the links between biology and behavior.

That's where Burnham, a Harvard economist, and Phelan, a UCLA biologist, come in. "Mean Genes" is clearly intended to be the popular treatise on genetics, sociobiology and the yin-yang of nature and nurture. From its eye-popping purple-and-orange book jacket to their sassy, conversational prose, the authors work hard not merely to explain some rather difficult scientific concepts, but make them sound fun and trendy. This is self-improvement for the semi-cerebral.

In the process, the genetic underpinnings of some pretty universal human conditions are revealed:

We are overweight because, in evolutionary terms, fat is good. Fat is energy stored for hard times. Early humans experienced lots of the latter, so any fat they acquired didn't last long. Modern humans don't often confront periods of extended hunger, or find themselves endlessly trekking across the savannah. As a result, our fat sticks around, accumulating.

Beauty isn't really defined by Madison Avenue or the fashion mavens. While details may vary with time and culture, the fundamental basis for what and who is beautiful are biologically based. In all societies and in both sexes, such aphrodisiacs as vigor, clear skin and symmetrical features are treasured. These suggest good genes and health, advertising their owner as an attractive mate.

Families are focal points for both the strongest bonds and most divisive conflicts. Shared genes reinforces the former, but it's not always enough to overcome individual interests. Conflict is a part of every human relationship, and sometimes the fiercest competition (for things like love or inheritance) comes from those closest to us.

The bottom line: Our genes influence us every day in almost every way. We are perpetually predisposed. This is a sobering thought, say the authors, but not necessarily an overwhelming one. Your life is still yours to fashion and mold. It just takes discipline and smarts -- provided you've been genetically endowed with enough of each.