Sam Harris (author) - Neuroscience

Neuroscience

Building on his interests in belief and religion, Harris completed a PhD in cognitive neuroscience at UCLA. He used fMRI to explore whether the brain responses differ between sentences that subjects judged as true, false, or undecidable, across a wide range of categories including autobiographical, mathematical, geographical, religious, ethical, semantic, and factual statements. Statements that were judged as "true" (belief) led to greater activation in the ventromedial prefrontal cortex than did statements that were judged as "false" (disbelief) both when examined across all categories, and when examined for mathematical judgments alone and for ethical judgments alone. Conversely, disbelief led to greater activation of left inferior frontal gyrus, right middle frontal gyrus, and bilateral anterior insular cortex.

When certainty (belief and disbelief) was compared against uncertainty, a widespread network of sub-cortical regions, including the head and tail of the caudate were activated. Uncertainty activated anterior cingulate cortex and superior frontal gyrus more than certainty did.

In another study, Harris and colleagues examined the neural basis of religious and non-religious belief using fMRI. Fifteen committed Christians and fifteen nonbelievers were scanned as they evaluated the truth and falsity of religious and nonreligious propositions. For both groups, statements of belief (sentences judged as either true or false) were associated with increased activation of ventromedial prefrontal cortex, a region of the brain involved in emotional judgment, processing uncertainty, assessing rewards and thinking about oneself.