, the description of the functional contributions of the two
core regions that are dysfunctional in psychopathy, and the data
indicating dysfunction in the functioning of these regions in
individuals with the disorder are presented. In this section, a
brief consideration of why this dysfunction may lead to the
development of the disorder is provided. As noted above, the
amygdala is crucial for stimulus–reinforcement learning and
responding to emotional expressions, particularly fearful
expressions that, as reinforcers, are important initiators of
stimulus–reinforcement learning. Moreover, the amygdala is
involved in the formation of both stimulus–punishment and
stimulus–reward associations. Individuals with psychopathy show
impairment in stimulus–reinforcement learning (whether
punishment or reward based) and responding to fearful and sad
expressions. It is argued that this impairment drives much of
the syndrome of psychopathy. Stimulus–reinforcement learning is
crucial for socialization, for learning that so