Research from Harvard University explores how instinct shapes our religious convictions here in America, where 92 percent of us believe in God

PROBLEM: According to a 2008 Pew survey on religion, 92 percent of Americans believe in God or a divine spirit, a figure that's strikingly close to the worldwide average. Still, in spite of the seeming universality of spiritual beliefs, why do some doubt their faith constantly while others believe wholeheartedly?

METHODOLOGY: Harvard University researchers conducted a series of experiments to see whether the strength of people's religious convictions is influenced by how much they trust their instincts over their reflections.

In one trial, 882 adults completed online questionnaires about their faith then answered a cognitive test designed to assess their thinking styles. This test involved some tricky problems that seemed intuitive. For example, one question stated: "A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?" The automatic answer is 10 cents, but the correct answer is five cents. Participants who made mistakes by relying on their hunches were considered intuitive thinkers, while those who apparently bothered to do a bit of algebra were considered reflective thinkers.