Two of the most endearing characters in Disney's "The Lion King" are the clownish pals Timon and Pumbaa. Timon is a know-it-all meerkat and Pumbaa a bumbling warthog, and late one night they are out on the savanna wondering about the origin of the stars. "They're fireflies," says Timon, "that got stuck in that big bluish-black thing." To which the less sophisticated Pumbaa replies, "Oh. I always thought they were balls of gas burning millions of miles away."
Pumbaa is scientifically correct, of course. That's why the joke is funny. But many children watching "The Lion King" would probably find Timon's theory more appealing. Kids seem to have a natural inclination to see the world as purposeful and things like stars primarily in terms of their function instead of their natural causes. Laboratory tests have shown this again and again: when psychologists ask children why mountains exist, most say they exist so animals have a place to climb. In kids' "theory" of the natural world, trees don't just happen to provide shade; making shade is their primary purpose. And so forth. In fact, unless there is really good evidence to convince kids otherwise, they want to see everything as having a precise function in the grand scheme of things.
But is this childish yearning for purpose and design simply a sign of cognitive immaturity, a primitive habit of mind that we grow out of as we age and our brains sprout new neuronal connections? Psychologists are very interested in how both kids and grown-ups explain the world, because our theories about stars and eyes and lakes are closely tied to our understanding of creation and creator—our personal cosmology.
University of California-Berkeley psychologist Tania Lombrozo suspected that the strong childhood preference for purposeful design might actually be a lifelong default position, one that is eclipsed but doesn't actually disappear as we gain experience and form beliefs —beliefs in gravity and plate tectonics and natural selection, for example—that constrain our explanations of things. And she figured out a way to test this provocative idea.
Lombrozo decided to study patients with Alzheimer's disease. She figured that dementia would weaken the entrenched causal beliefs of adulthood, and that with their beliefs so compromised, adults would show their true cognitive colors. To test this idea in the laboratory, she gave Alzheimer's patients the same cognitive tests that are used with children, basically consisting of a series of questions with two possible answers. For example, she might ask, "Why is there rain? Is it because water condenses in clouds and forms droplets, or does rain exist so we will have water for drinking?" Other questions she used: "What is the sun for? How about trees?"
Well, guess what. Alzheimer's patients think the primary purpose of rain is to provide drinking water, that trees exist to provide shade and that the sun is up in the sky for the sole purpose of keeping us warm. Healthy adults, by contrast, while they know the sun warms us, also know the sun does not exist for that reason. It's a subtle but important distinction. The Alzheimer's patients' thinking mirrors the rudimentary thinking of children, and suggests that the urge for design and functionality is never really outgrown. There is, Lombrozo argues in the November issue of Psychological Science, a fundamental human urge to comprehend the world as purposeful.
There is an intriguing twist, however. Lombrozo did a second study with the same people, asking whether the order in the universe was caused by God or by some process like evolution or plate tectonics. In other words, do design and purpose require a designer? And the answer appears to be no. Even though the patients tended to see the world as designed and purposeful, they were no more likely to presume that a supernatural designer is behind the natural order of things. So our lifelong impulse is to see the world as ordered and purposeful; some of us add the God part on, but it's not necessary to explain the brain's urge for order.