There is a great deal of behavioral evidence in support of this model. For example, damage to the OFC, and perhaps damage specifically to the VM PFC, results in affective lability and rash action. In card-playing tasks characterized by uncertainty concerning the experience of rewards and penalties, normal controls begin to develop skin conductance responses (SCR's), indicative of arousal and affective responding, in anticipation of card choices that may be punishing. Individuals with PFC damage, and with OFC damage in particular, do not; they do not appear to have the normal anticipatory affective response to potential punishment (Bechara, 2004; Bechara, Tranel, Damasio, & Damasio, 1996; Cardinal et al., 2002). Interestingly, normal individuals develop anticipatory SCR when pondering a choice that turned out to be risky, before they knew explicitly that it was a risky choice, whereas OFC-damaged patients do not develop anticipatory SCR's, even when they eventually can articulate which choices are risky (Bechara, Damasio, Tranel, & Damasio, 1997). Thus, OFC damage appears to impair affective anticipation of potential risk to one's actions.
