Last week, Gallup announced the results of their latest survey on Americans and evolution. The numbers were a stark blow to high-school science teachers everywhere: forty-six per cent of adults said they believed that “God created humans in their present form within the last 10,000 years.” Only fifteen per cent agreed with the statement that humans had evolved without the guidance of a divine power.
What’s most remarkable about these numbers is their stability: these percentages have remained virtually unchanged since Gallup began asking the question, thirty years ago. In 1982, forty-four per cent of Americans held strictly creationist views, a statistically insignificant difference from 2012. Furthermore, the percentage of Americans that believe in biological evolution has only increased by four percentage points over the last twenty years. Such poll data begs the question: Why are some scientific ideas hard to believe in? What makes the human mind so resistant to certain kinds of facts, even when these facts are buttressed by vast amounts of evidence?
A new study in Cognition, led by Andrew Shtulman at Occidental College, helps explain the stubbornness of our ignorance. As Shtulman notes, people are not blank slates, eager to assimilate the latest experiments into their world view. Rather, we come equipped with all sorts of naïve intuitions about the world, many of which are untrue. For instance, people naturally believe that heat is a kind of substance, and that the sun revolves around the earth. And then there’s the irony of evolution: our views about our own development don’t seem to be evolving.
This means that science education is not simply a matter of learning new theories. Rather, it also requires that students unlearn their instincts, shedding false beliefs the way a snake sheds its old skin.
To document the tension between new scientific concepts and our pre-scientific hunches, Shtulman invented a simple test. He asked a hundred and fifty college undergraduates who had taken multiple college-level science and math classes to read several hundred scientific statements. The students were asked to assess the truth of these statements as quickly as possible. To make things interesting, Shtulman gave the students statements that were both intuitively and factually true (“The moon revolves around the Earth”) and statements whose scientific truth contradicts our intuitions (“The Earth revolves around the sun”).
As expected, it took students much longer to assess the veracity of true scientific statements that cut against our instincts. In every scientific category, from evolution to astronomy to thermodynamics, students paused before agreeing that the earth revolves around the sun, or that pressure produces heat, or that air is composed of matter. Although we know these things are true, we have to push back against our instincts, which leads to a measurable delay.
What’s surprising about these results is that even after we internalize a scientific concept—the vast majority of adults now acknowledge the Copernican truth that the earth is not the center of the universe—that primal belief lingers in the mind. We never fully unlearn our mistaken intuitions about the world. We just learn to ignore them.