There is no polite way to say this: people who resist scientific explanations for natural phenomena such as the age of the earth and the fact of evolution are guilty of childish thinking.

So argue two experts in cognitive and developmental psychology, the science of how thinking and other mental functions change as people grow up. “Resistance to certain scientific ideas,” Paul Bloom and Deena Skolnick Weisberg of Yale University argue in the May 18 issue of the journal Science, is largely a result of patterns of thinking that are characteristic of young children but which, in some people, “persist into adulthood.”

Scientists bemoan the huge numbers (42 percent, in a 2005 poll) of Americans—and this does seem to be more an American phenomenon than a European or east Asian one—who believe that humans and all other animals have existed in their current form since their first appearance on Earth, despite fossil and genetic evidence showing that, to the contrary, species change over time in the process of evolution. Tens of millions believe—again, contrary to scientific evidence—that unproved medical therapies work, that out-of-body experiences are real (rather than results of particular brain activity), and that astrology has merit, for instance. But if you look at what children think and how they learn, the resistance to science and the persistence of unscientific thinking doesn’t look so surprising.

We come into the world with preconceived ideas about how that world works; like a computer, we’re pre-loaded with some programs and knowledge. Babies know that objects fall unless held up, for instance (scientists test for this knowledge by noting what surprises babies, and an object defying the law of gravity definitely does). Little kids know that people act according to goals. They believe that actions and situations have purposes.