THE COVERT LEARNING OF AFFECTIVE VALENCE DOES NOT REQUIRE STRUCTURES IN HIPPOCAMPAL SYSTEM OR AMYGDALA

Following bilateral damage to the entire medial temporal lobe and interconnected cortices in the anterior temporal and medial frontal regions, patient Boswell developed a severe learning defect for all types and levels of factual knowledge, including faces. In the experiments described here, however, we demonstrate that Boswell can acquire a nonconscious bond between entirely new persons and the affective valence they display. The finding is important on the followng accounts. First, Boswell's lesions guarantee that the entorhinal and perirhinal cortices, hippocampus, amygdala, and higher-order neocortices in the anterior temporal region are not required to support this form of covert learning. Second, this demonstration is possible only in a patient such as Boswell, because in individuals with normal or only partially impaired factual learning, fact memory will contaminate the performance.