A neuro-imaging study shows that personal values people refuse to disavow, even when offered cash, are processed differently in the brain than those values that are willingly sold. The experiment found that the realm of the sacred -- whether a strong religious belief, national identity or code of ethics -- is a distinct cognitive process, and prompts greater activation of a brain area associated with rules-based, right-or-wrong thought processes, as opposed to regions linked to costs-versus-benefits thought.