The extent to which motivational mechanisms contribute to reward seeking processes is crucial to our understanding of certain abnormal behaviours, including addiction. Pavlovian conditioning endows reward-associated stimuli with the ability to modulate goal-directed actions for that same reward (Pavlovian-to-Instrumental transfer; PIT). Learning and motivational theories attempt to describe the processes by which stimuli in the environment acquire incentive properties, attract attention and drive reward-seeking behaviours and bear many resemblances, but there are also important differences. This thesis uses a general PIT model in humans to further our understanding of these discrepancies and investigates the effect mood has on these processes. Firstly, altering the value of the reward affected the rigor of instrumental performance, but the same changes in outcome value did not affect the expectancy of, attention to, or emotional reactivity to the cues suggesting that in Pavlovian learning, apart from the nature of outcomes, the value of outcomes is encoded such that changes in outcome value prevent transfer of a Pavlovian cue's incentive properties to alter goal-directed action. Secondly, the further papers assess the extent to which mood modulates this same action. When under negative mood a general reduction in motivation, driven by an attenuated sensitivity to the reward was observed, as well as a dissociation between aversive and appetitive outcomes. The remaining study explored whether mood altered Pavlovian learning and revealed that those under state negative mood take longer to express their knowledge explicitly and that those under positive mood showed altered attention and emotional responses towards the same stimuli. The approach used in this thesis shows the merits of both motivational and learning theories, and further demonstrates the link between mood and motivation. Additionally, a dissociation between punishment and reward prediction when under negative mood was demonstrated and builds upon this important distinction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:655559 |
| Date | January 2015 |
| Creators | Mathers, Claire |
| Publisher | University of Sussex |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://sro.sussex.ac.uk/id/eprint/54342/ |
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