Your nose is one of the less complicated parts of your body, and yet we credit it with considerable intelligence in the area of truth vs. falsehood. We "sniff out a lie." We say "something smells fishy." Now studies suggest that something more than metaphor may be at work here--specifically, brain science. The same research may also shed unexpected light on religious faith.
Believing or disbelieving something is always as much about feeling as fact. Sam Harris, a doctoral candidate at UCLA, wanted to see what that means in physiological terms. To many readers, Harris is best known for his antireligious book The End of Faith. But he is also a neuroscientist. In a study reported in the Annals of Neurology, Harris presented 14 people with 360 statements designed to elicit belief, disbelief or uncertainty. He tracked their brain response with a functional magnetic resonance imager (fMRI) and got some very revealing results.
Statements like "2 + 2 = 5" and "Torture is good" caused an area called the anterior insula to light up. True statements like "2 + 2 = 4" activated the ventromedial prefrontal cortex. The ventromedial is thought to play a role in judgment, memory, fear and, according to one study, soft-drink preferences. The anterior insula helps process fear, disgust and reactions to bad smells.
This is not the only study to have suggested that disbelief and moral outrage may be processed in the area of the brain that makes us go "Blechh." Sam Bowles, professor of human behavior at the Santa Fe Institute, describes research in which an unfair business deal produced a response in the same region. How did disgust get involved in the belief-and-disbelief business? Some think it started as a fairly straightforward adaptation to enable a suspicious taste, smell or appearance--like that of vermin--to trigger the impulse to eliminate the source. We may have then generalized that reaction to ideas. "When someone says something you disbelieve," Harris says, "it has a kind of emotional tone. Rejecting someone's statement as illogical or incompatible feels like something."
Harris guesses that if the anterior insula collaborates in prompting distaste for such disparate things as bad math, waterboarding and sour milk, it may also act when a religious believer recoils at the statement "God is dead." His next trial will test religious belief and disbelief. Can he remain unbiased? He points out that it's impossible to prove or disprove God's existence just by studying what humans think is true or false. Faith, however, is more vulnerable. He admits that those who regard faith as a communion with the divine, at least partly independent of body chemistry, may object if he shows that it is "essentially the same as other kinds of knowing or thinking." Pictures from an fMRI would not make that case definitively--but Harris knows that nobody is likely to produce competing photos of the divine part.