The processes involved in complex human decision-making, and their neural
underpinnings, have been the subject of much investigation in recent years (e.g.
Damasio, 1994; Eslinger & Damasio, 1985). It has been postulated that emotion
plays a cmcial role in decision-making, with especial emphasis on the involvement of orbitofrontal cortex ( e.g. Bechara, Damasio, Damasio & Anderson, 1994; Damasio, Tranel & Damasio, 1990).
The emotional valencing of events as good or bad, positive or negative, rewarding or punishing, is critical in promoting advantageous human behaviour (e.g. Rolls, 1999). It has been claimed that the ability to use 'affective' information from past events, facilitates the guidance of decision-making. This emotion-based learning, perhaps more traditionally defined as ' intuition' (Damasio, 1994, p.187), appears to be essential in shaping adaptive behaviour- most clearly demonstrated by the failures in decision-making in those with lesions to the ventromedial frontal lobes.
This PhD thesis involves a number of adaptations to the well-known Iowa GamblingTask paradigm (Bechara, et al, 1994), with additional measures of skin conductance and subjective experience (e.g. Bechara, Tranel, Damasio, & Damasio, 1996; North & O'Carroll, 2001). The thesis presents a series of 14 investigations, which assess two central issues in the interaction between emotion and human decision-making: the nature of reward, and the modification of reward contingencies, in emotion-based learning.
The investigations involve varying type of reward incentive, assessing explicit
awareness of rewarding contingencies, and considering the effect of situational
complexity. The modification of reward contingencies in emotion-based learning
were explored by assessing decision-making before and after the reassignment of contingency values.
The key findings showed that emotion-based learning is: a robust phenomenon;
which can, but does not necessarily occur in explicit awareness; is independent of task complexity; is flexible; does not necessarily depend on physiological
experience; and finally, is impaired in neurologically normal individuals known to have modifications in the experience of emotion.