Faulty Powers

The human brain is a less-than-perfect device. A new book explains how our minds work … and sometimes don't.
Raina Kelley
Newsweek Web Exclusive
Updated: 4:41 PM ET May 8, 2008

Despite the fact that humans have been known to be eaten by bears, sharks and assorted other carnivores, we love to place ourselves at the top of the food chain. And, despite our unwavering conviction that we are smarter than the computers we invented, members of our species still rob banks with their faces wrapped in duct tape and leave copies of their resumes at the scene of the crime. Six percent of sky-diving fatalities occur due to a failure to remember to pull the ripcord, hundreds of millions of dollars are sent abroad in response to shockingly unbelievable e-mails from displaced African royalty and nobody knows what Eliot Spitzer was thinking.

Are these simply examples of a few subpar minds amongst our general brilliance? Or do all human minds work not so much like computers but as Rube Goldberg machines capable of both brilliance and unbelievable stupidity? In his new book, "Kluge: The Haphazard Construction of the Human Mind," New York University professor Gary Marcus uses evolutionary psychology to explore the development of that "clumsy, cobbled-together contraption" we call a brain and to answer such puzzling questions as, "Why do half of all Americans believe in ghosts?" and "How can 4 million people believe they were once abducted by aliens?"

According to Marcus, while we once we used our brains simply to stay alive and procreate, the modern world and its technological advances have forced evolution to keep up by adapting ancient skills for modern uses--in effect simply placing our relatively new frontal lobes (the home of memory, language, speech and error recognition) on top of our more ancient hindbrain (in charge of survival, breathing, instinct and emotion.) It is Marcus's hypothesis that evolution has resulted in a series of "good enough" but not ideal adaptations that allow us to be smart enough to invent quantum physics but not clever enough to remember where we put our wallet from one day to the next or to change our minds in the face of overwhelming evidence that our beliefs are wrong. "Evolution is conservative and stingy," Marcus tells NEWSWEEK. "It uses what it has. It doesn't start over--as a statistical matter, something is much more likely to evolve if it involves tinkering."

A kluge (rhymes with "huge") is defined as a clumsy or inelegant solution to a problem. Marcus's finest example is the contraption used by the Apollo 13 astronauts to get home after their CO2 filters began to fail--using a plastic bag, cardboard box, some duct tape and a sock, they were able to cobble together a new filter and get home safely. Despite the fact that it worked, NASA has never been tempted to incorporate that design into its space projects.

In his attempt to define the "klugey-ness" of the human mind, Marcus would have us look no further than our memories, which he describes as "the mother of all kluges." Unlike computers, we cannot readily recollect all that we've remembered. Turns out, our memory is driven by cues. We need hints and context to remember where we put our purse ("Retrace your steps"). To free associate from one memory to the next may, Marcus writes, "lead depressed people to seek out depressive activities, such as drinking or listening to songs of lost love, which presumably deepens the gloom as well."

Yet another problem with our contextual memory is that memories tend to run together and are prone to contamination. I clearly remember being 5 years old and watching my mom hit my dad in the face with a Boston cream pie. The only problem is that it never happened. It was a dream that, for some reason, I remember as fact. Marcus believes our memory evolved in this way in an attempt to prioritize memories since our brains are much slower than the memory system available to computers and our neurons cannot keep all our recollections at hand for immediate retrieval. It's a workable system but one that doesn't allow us the time or ability to check memories for accuracy as a computer would be able to.

If visions of tearing your apartment apart looking for that receipt you saw five minutes ago aren't enough to convince you of the klugey-ness of our minds, take a minute and read your horoscope. Mine says: "Because of financial gains lately, you could fall into a new way of thinking and spend money too quickly. Be aware of this and take an attitude of easy-does-it." That actually means something to me despite its bland generality (I just got paid!) and odds are that your horoscope will somehow also carry a ring of truth. For some reason, the more general or vague a descriptive statement is, the greater the human tendency to believe that it is specifically about us. Late-night infomercials and used-car salesmen also use this weakness to sell us things we don't need or cars that don't work.

And why are humans so prone to believe absolutely anything from the existence of the Loch Ness monster to Atlantis? Marcus explains that "evolution has left us distinctly gullible … the systems that underlie our capacity for belief are powerful, they are also subject to superstition, manipulation and fallacy. Beliefs, and the imperfect neural tools we use to evaluate them, can lead to family conflicts, religious disputes and even war." Again, he argues our brains didn't evolve in a way that allowed us to thoroughly evaluate how well our beliefs represent reality.

Our older subconscious brain moves reflexively ("We're hungry, eat that mushroom now"), while our newer prefrontal cortex struggles to catch up with other alternatives ("Check your guidebook to see if it's poisonous or wait until we get to camp and eat some gorp"). Marcus theorizes that "the human tendency to most clearly remember information that seems consistent with our beliefs [or emotions] makes it very hard to let those beliefs go." So the next time you get into an argument with your spouse and he or she snaps, "You only hear what you want to hear," you can reply, "We all do. We've evolved that way."

But before you despair that humans are doomed to a life of lost keys, irrational beliefs and false memories, Marcus does supply us with a whole host of ways to trains our brains to act more rationally. My personal favorite is his first, "Whenever possible, consider alternative hypotheses." He recommends forcing yourself to come up with a list of alternatives even if you are absolutely certain that your husband is breaking drinking glasses out of spite and not because the sink is a little too deep for its intended purposes. Some of his other tips also involve forcing your brain to get out of the habit of relying on its more instinctual (and less reliable) thought processes and practice using our more conscious frontal lobes. This kind of advice may seem obvious when you read them but try and think about the last time you actually took advice such as, "Whenever possible, don't make important decisions when you are tired or have other things on your mind." Or "Always weigh benefits against costs."

Sounds easy but as Marcus notes, few of us rarely consider what else we could be doing that's of more value (spending time with your partner or family, calling up an old friend, writing a thank-you note) than watching a "CSI" marathon on TV. And if worst comes to worst, and you lose your keys and are late to work because of it, you can simply tell your boss, it's my brain's fault.