Each subject lay in the scanner for about an hour while we projected on a small screen a series of cigarette package labels from various countries — including statements like “smoking kills” and “smoking causes fatal lung cancers.” We found that the warnings prompted no blood flow to the amygdala, the part of the brain that registers alarm, or to the part of the cortex that would be involved in any effort to register disapproval.
To the contrary, the warning labels backfired: they stimulated the nucleus accumbens, sometimes called the “craving spot,” which lights up on f.M.R.I. whenever a person craves something, whether it’s alcohol, drugs, tobacco or gambling.
I don’t know if we needed (dubious?) brain-scan imaging to tell us that the economy of human desire operates beyond the pleasure principle.
