Most people, regardless of race, religion or culture, believe they are immortal. That is, people believe that part of themselves-some indelible core, soul or essence-will transcend the body's death and live forever. But what is this essence? Why do we believe it survives? And why is this belief so unshakable?

A new Boston University study led by postdoctoral fellow Natalie Emmons and published in the January 16, 2014 online edition of Child Development sheds light on these profound questions by examining children's ideas about "prelife," the time before conception. By interviewing 283 children from two distinct cultures in Ecuador, Emmons's research suggests that our bias toward immortality is a part of human intuition that naturally emerges early in life. And the part of us that is eternal, we believe, is not our skills or ability to reason, but rather our hopes, desires and emotions. We are, in fact, what we feel.

Emmons' study fits into a growing body of work examining the cognitive roots of religion. Although religion is a dominant force across cultures, science has made little headway in examining whether religious belief-such as the human tendency to believe in a creator-may actually be hard-wired into our brains.

"This work shows that it's possible for science to study religious belief," said Deborah Kelemen, an Associate Professor of Psychology at Boston University and co-author of the paper. "At the same time, it helps us understand some universal aspects of human cognition and the structure of the mind."

Most studies on immortality or "eternalist" beliefs have focused on people's views of the afterlife. Studies have found that both children and adults believe that bodily needs, such as hunger and thirst, end when people die, but mental capacities, such as thinking or feeling sad, continue in some form. But these afterlife studies leave one critical question unanswered: where do these beliefs come from? Researchers have long suspected that people develop ideas about the afterlife through cultural exposure, like television or movies, or through religious instruction. But perhaps, thought Emmons, these ideas of immortality actually emerge from our intuition. Just as children learn to talk without formal instruction, maybe they also intuit that part of their mind could exist apart from their body.

Emmons tackled this question by focusing on "prelife," the period before conception, since few cultures have beliefs or views on the subject. "By focusing on prelife, we could see if culture causes these beliefs to appear, or if they appear spontaneously," said Emmons.