Kluge: The Haphazard Construction of the Human Mind (Houghton Mifflin; 2008)

The problem, of course, is not that we put things off, per se; if we need to buy groceries and do our taxes, we literally can't accomplish both at the same time. If we do one now, the other must wait. The problem is that we often postpone the things that need to get done in favor of others — watching television or playing video games

— that most decidedly don't need to get done. Procrastination is a sign of our inner kluge because it shows how our top-level goals (spend more time with the children, finish that novel) are routinely undermined by goals of considerably less priority (if catching up on the latest episodes of Desperate Housewives can be counted as a "goal" at all).

People need downtime and I don't begrudge them that, but procrastination does highlight a fundamental glitch in our cognitive "design": the gap between the machinery that sets our goals (offline) and the machinery that chooses (online, in the moment) which goals to follow.

The tasks most likely to tempt us to procrastinate generally meet two conditions: we don't enjoy doing them and we don't have to do them now. Given half a chance, we put off the aversive and savor the fun, often without considering the ultimate costs. Procrastination is, in short, the bastard child of future discounting (that tendency to devalue the future in relation to the present) and the use of pleasure as a quick-and-dirty compass.

We zone out, we chicken out, we deceive. To be human is to fight a lifelong uphill battle for self-control. Why? Because evolution left us clever enough to set reasonable goals but without the willpower to see them through.

Alas, zoning out and chickening out are among the least of our problems; the most serious are the psychological breakdowns that require professional help. From schizophrenia to obsessive-compulsive disorder and bipolar disorder (also called manic depression), nothing more clearly illustrates the vulnerability of the human mind than our susceptibility to chronic and severe mental disorders. What explains the madness of John Nash, the bipolar disorder of Vincent van Gogh and Virginia Woolf, the paranoia of Edgar Allan Poe, the obsessive-compulsive disorder of Howard Hughes, the depression that drove Ernest Hemingway, Jerzy Kosinski, Sylvia Plath, and Spalding Gray to suicide? Perhaps a quarter of all human beings at a given moment suffer from one clinical disorder or another. And, over the course of a lifetime, almost half the population will face bouts of one mental illness or another. Why is our mind so prone to breakdown?

Let's start with a fact that is well known but perhaps not fully appreciated. For the most part, mental disorders aren't random unprecedented anomalies, completely unique to the individuals who suffer from them. Rather, they comprise clusters of symptoms that recur again and again. When things fall apart mentally, they tend to do so in recognizable ways, what engineers sometimes call "known failure modes." A given make and model of a car, say, might have a fine engine but consistently suffer from electrical problems. The human mind is vulnerable to its own particular malfunctions, well documented enough to be classified in the human equivalent of Chilton's Auto Repair: the DSM-IV (short for Diagnostic and Statistical Manual of Mental Disorders, fourth edition; a fifth edition is scheduled for 2011).

To be sure, symptoms vary among individuals, both in severity and in number. Just as no two colds are exactly alike, no two people diagnosed with a given mental illness experience it in precisely the same way. Some people with depression, for example, are dysfunctional, and some aren't; some people with schizophrenia hear voices, and others don't.

And diagnosis remains an inexact science. There are a few disorders (such as multiple personality syndrome) whose very existence is controversial, and a few "conditions" used to be labeled as disorders but never should have been (such as homosexuality, removed from the DSM-III in 1973).* But by and large, there is an astonishing amount of consistency in the ways in which the human mind can break down, and certain symptoms, such as dysphoria (sadness), anxiety, panic, paranoia, delusions, obsessions, and unchecked aggression, recur again and again.

When we see the same basic patterns over and over, there has to

* In an earlier era, there was "the inability to achieve vaginal orgasm," "childhood masturbation disorder," and drapetomania, the inexplicable desire on the part of some slaves to run away, or what I like to think of as freedom sickness.

be a reason for them. What is the mind, such that it breaks down in the ways that it does?