Novelty assessment in the brain and long-term memory encoding.

Recent positron emission tomography (PET) studies have identified neuronal components of widespread novelty-assessment networks in the brain. We propose that the efficacy of encoding on-line information into long-term memory depends on the novelty of the information as determined by these networks, and report a test of this "novelty/encoding" hypothesis. Subjects studied a list of words. Half of the words were "familiar" by virtue of their repeated presentation to the subjects before the study of the critical list; the other half were novel, in that they had not previously been encountered in the experiment. The results conformed to the prediction of the novelty/encoding hypothesis: accuracy of explicit (episodic) recognition was higher for novel than for familiar words.