When I was working on a 2007 column and then a longer story last year about why people believe in paranormal and supernatural phenomena, one of the most insightful scientists I spoke to was psychology researcher Bruce Hood of Britain’s University of Bristol. As he does in his blog, he explained that believing in ghosts, ESP, telepathy or even that you can tell when someone is looking at you from behind is not a matter of religion or culture, but instead reflects the normal workings of the brain.

Now Hood has a new book called Supersense that delves into “why we believe in the unbelievable,” as his subtitle puts it. “Humans are born with brains designed to make sense of the world and that sometimes leads to beliefs that go beyond any natural explanation," he argues. "We are inclined from the start to think that there are unseen patterns, forces and essences inhabiting the world. . . . This way of thinking is unavoidable, and it may be part of human nature to see ourselves connected to each other at this deeper level.”

The numbers alone support his argument that many people—a lot of them smart and highly educated—believe in supernatural phenomena. Polls show that 73 percent of U.S. adults believe in at least one supernatural phenomenon (41% in ESP, 37% in haunted houses, 32% in ghosts, 31% in telepathy, 26% in clairvoyance, 21% in communicating with the dead). And superstitions are rampant. Tony Blair wore the same pair of shoes to answer Parliamentarians’ questions. John McEnroe made sure not to step on the lines as he walked on or off a tennis court during a tournament. John McCain carries a lucky feather and lucky coins. Barack Obama, having played basketball on the morning of the day he won the Iowa caucuses, played every other primary and caucus day thereafter. These and other “secular rituals,” as Hood calls them, show that “everyone is susceptible to supernatural beliefs.”

These beliefs are supported by what we think are personal experiences of the supernatural—having a premonition that someone is about to call and then hearing their voice when we answer the phone, for instance. Indeed, people cite such first-hand experiences of the supernatural, not religious teachings, for their belief in it. And once we believe, we find ever-more evidence to support that belief, due to “confirmatory bias,” the well-established psychological phenomenon of noticing and remembering events that confirm a belief and forgetting those that challenge it. Don’t you remember the times your premonitions were right (besides that phone call, maybe that something bad would happen to someone) and forget the times you were wrong? I bet McEnroe would vividly remember any time he lost a match because he inadvertently stepped on a line.

The core of the book is an examination of the brain processes that underlie that susceptibility, the “mind design” in which supernatural beliefs originate. For instance:

• As children (and often as adults), we believe that minds and bodies are separate entities, not that the mind is what the brain does. From there, it is a short step to belief in telepathy and spirits, minds that are not tethered to physical bodies.
• We have brain circuitry dedicated to perceiving faces, which stands us in good stead when we need to recognize mom but also causes us to see Jesus in a grilled cheese sandwich. That exaggeration of a useful brain function, argues Hood, is adaptive: “If you are in the woods and suddenly see what appears to be a face, it is better to assume it is one rather than ignore it. It could be another person out to get you.”
• Similarly, babies tend to treat moving objects as if they had purpose, rather than as following, say, a gravitational trajectory. Children “naturally assume that the living world is permeated by invisible life forces [and] energies,” notes Hood. That lays the groundwork for imputing aspects of mind and intentionality to inanimate objects. From there it is a small step to believing that the sweater of a killer, in one of Hood’s favorite examples, is imbued with the murderer’s spirit. “This way of thinking emerges early and may support a supersense that there are secret agents operating throughout the world,” he writes.

I disagree with Hood when he argues that a sentimental attachment to objects reflects superstitious beliefs, namely that the essence of the person or place resides in the article of clothing or other memento. For many of us, the object is a powerful reminder of someone or someplace, not something spooky. Nor am I convinced that collectors of memorabilia are motivated by a spooky sense of supernatural connectedness—the “tendency to see objects as possessing invisible properties that originate from significant individuals,” in Hood's words—rather than a simple desire to be reminded of something. (“Few things are more irrational that the human obsession for collecting,” he argues unpersuasively.) And Hood is too kind to supernatural beliefs when he credits them with enabling us to share the “sacred values” that bind together our societies. Given recent events, I think we could use fewer sacred values (jihads, promised lands . . . ) and more values rooted in justice, compassion and altruism.

Still, this is a fun and illuminating book. Oh, and about the common belief that we can tell when someone we cannot see is looking at us. If you’ve ever had such a feeling, you probably turned around suddenly. That movement, Hood argues, likely caused the people around you to look at you, wondering why you were spinning around. But seeing them look at you confirmed your belief in your (supernatural) power to detect unseen gazes. But think: do you remember the times when you spun around and no one was looking at you?