Norman N. Holland, author of Literature and the Brain, replies:
Although we know a fair amount about the brain activity linked with reading, no one has isolated the mechanisms tied specifically to suspension of disbelief. Yet we can extrapolate how the brain behaves on a more general level.
Poet Samuel Taylor Coleridge coined the term “suspension of disbelief” in 1817, but almost two centuries would lapse before we could infer how the brain might support this puzzling phenomenon. Coleridge asked readers of his fantastical poems, including The Rime of the Ancient Mariner, to give him “that willing suspension of disbelief for the moment, which constitutes poetic faith.” That phrase, “poetic faith,” encapsulates what our brain is doing. It isn't that we stop disbelieving—it's that we believe two inconsistent things. We accept that we are sitting and reading or watching a movie. We also believe or, more accurately, feel that what we are reading or viewing is happening.
Action is the key. When we are reading a story or watching a movie, we know that we cannot or will not act to change what is occurring, a phenomenon philosopher Immanuel Kant called disinterestedness. Yet because we are not going to act, the brain economizes. We turn off the neural processes that tell us we might need to do something about what we are seeing. The prefrontal cortex does not try to assess the reality of what we are seeing, nor does it trigger motor impulses. That is why when we are sitting in a theater, we do not jump out of our seats to save the blond starlet even though we know she is about to get chopped up by a chainsaw-wielding fiend.
Losing ourselves refers to another element of poetic faith, when the audience is, in the psychologists' term, “transported.” We cease to be aware of our body, our posture or our environment. No longer are we in our living room or able to see the cinema's glowing exit sign. Perhaps most important, our limbic system causes us to feel emotions—anger, disgust, jealousy, desire, fear—about the stories we are watching or reading.
Being transported emotionally into an alternative reality helps us to invest more completely in a piece of fiction, no matter how unbelievable. Thus, we are able to believe in the supernatural occurrences in Coleridge's Ancient Mariner, the inhuman strength and speed of Superman, or the harrowing journey of a Hobbit in his quest to destroy an evil ring.