Thu, February 12, 2009
Sci-Tech > Science > Happy Birthday Charles Darwin

Keeping pace with change

2009-02-12 08:20:55 GMT2009-02-12 16:20:55 (Beijing Time)  Forbes

Why it matters that behaviors evolve.

Sure, we can rightly congratulate ourselves on having had the good sense to recognize the achievements of Charles Darwin. In his anniversary year, we celebrate how his insights brought delicately linking inter-coherence to vast webs of life. And we take stock of advances that continue to flow from his core ideas.

For example, we see that overuse of antibiotics winnows the weakest microbes, speeding the ascendance of more resistant strains.

And we now know that a seemingly enlightened policy of netting only the biggest fish--leaving smaller juveniles to grow into next year's duplicate catch--won't work as well as we expected. Taking the biggest fish each year creates an evolutionary selection pressure: being big is bad. Over generations, this leads not only to adults of smaller maximum size but also to shrinking populations, since smaller adults have fewer offspring.

In these and myriad other ways, we have come to understand that species are not static.

They exist on evolutionary time scales as fleeting bundles of traits, the intermixing benefits of which will rise and fall as environments change. Selection pressures matter, because they (alongside other evolutionary processes) shape the physical characteristics of species over time.

But this is no time for laurel-resting. Evolution, as it is sometimes put, does not stop at the neck. Animals are choice machines--for the simple reason that a well-adapted body gets nowhere without well-adapted behavioral inclinations to deploy that body effectively.

Inevitably, species bear behavioral leanings that are rather narrowly tailored to the anatomical and environmental conditions in which they have typically found themselves.

More starkly, core, heritable behavioral predispositions are always along for this grand, thrilling and dangerous evolutionary ride. They may be less visible, more flexible, more contingent and more variable than anatomy in response to environmental conditions. But come they will, and ignoring this fact can cost us.

As usual, however, even the simplest principle plays out in complex realities. The human brain, for example, is merely 3% of a person's mass. Yet it is a hungry machine, consuming 20% to 25% of the energy we eat.

What is our return on this investment? For starters, a very big brain. Compared with other primates, we are born remarkably premature (and with considerable difficulty); at the last moment, it's still possible to get an absurdly ballooning brain-case through the pelvic opening.

But these caloric and physical costs buy us a neural network so complex and powerful that we can communicate, cooperate and compose in gloriously exquisite and unparalleled ways. (And also outfox each other in pursuit of things that matter, like resources.)

So where's the problem? The problem is the accelerating pace of change. Automatic weapons; tax-deferred, interest-bearing retirement accounts; sophisticated financial swindles.

Behavioral tendencies that once served us well now bump up against novel environmental features that can render them outdated at best--or even affirmatively harmful. And the faster the pace of change, the more opportunity for costly misfits between evolved inclinations and technically superior choices.

Which brings us, unexpectedly, to law. Broadly speaking, law deals in the currency of behavior. And because legal systems are tasked with furthering society's wide-ranging behavioral goals (fight less; stand behind bargains; save enough for retirement), the effects of evolutionary processes on behaviors can pose unexpected challenges.

For example, we like to think people will respond rationally to changes in legally imposed incentives. We expect that as penalties increase, bad behavior will always (and, in the end, sufficiently) decrease. We craft our laws accordingly.

But people are stubbornly irrational in many contexts. Moreover, they are often irrational in common patterns. Evolutionary analysis suggests that some of these contexts and patterns could be better anticipated by creating a more robust understanding of the many influences--including evolutionary ones--that converge in the behaviors that society seeks to change or channel. If so, that approach could yield incremental improvements in the effectiveness and efficiency of policies to pursue society's own pre-articulated ends.

The point is not that evolutionary processes can tell us what we should want to accomplish. They logically cannot. The point is this: Once we know what we want, a deeper, wider and richer understanding of the effects of evolutionary processes on the world around us--and, more important, within us--may help get us there.

(Owen D. Jones,

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