Davies-Owen, Jennifer
(2019)
Exploring single trial appetitive conditioning and the modulation of attention.
PhD thesis, University of Liverpool.
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Abstract
Pavlovian conditioning processes may be central to hedonic overeating. The following experiments were conducted to explore how learning shapes motivational and attentional processes that might enhance reactivity to food-related cues. A primary aim was to explore the efficacy of a novel, naturalistic appetitive conditioning procedure, first described by Blechert et al. (2016), for producing rapid conditioned responses in as little as a single conditioning trial. This novel paradigm was designed to mimic a real-life experience with a new food, from the initial sight, smell and touch, to consumption. Subjective measures of craving, expectancies and liking tapped in to explicit motivational processes, and an Emotional Blink of Attention (EBA) task, originally reported by Piech, Pastorino & Zald (2010), was used to explore implicit attentional processes. The degree of incentive salience acquired by newly learned cues was measured as the extent to which they captured attention in a rapid serial visual presentation task (RSVP), preventing accurate target detection in a phenomenon known as an attentional blink. Experiments 1 and 2 (Chapter 3) failed to show evidence for appetitive conditioning on explicit measures, which I suggest can be attributed to the relatively low reward value of the food item chosen for conditioning (marzipan). Findings presented in Chapters 4 – 7 found more convincing evidence that appetitive conditioning shapes motivational processing of newly learned food cues; after a single pairing, an edible object made from a highly rewarding foodstuff (chocolate) elicited cravings, expectancies for chocolate and was perceived as more highly pleasant than a visually similar plastic object. Experiment 4 (Chapter 5) demonstrated that additional trials did not enhance conditioning, supporting the view that single trial learning with hedonic food rewards is a powerful phenomenon. Furthermore, Chapter 6 demonstrated how this learning spreads to cues varying in their similarity to the original conditioned stimulus via generalisation. A consistent finding throughout Chapters 3-6 was that attentional processing was modulated by this naturalistic conditioning procedure, although not as originally predicted. After just one conditioning trial, both reinforced and non-reinforced cues captured attention more readily than neutral cues, suggesting salience acquisition independent of reward. Whilst Chapter 4 confirmed that reward-paired cues acquire greater salience than novel or familiar cues after a single exposure, it seems that the novelty has a synergistic influence over this process. I suggest that contextual novelty, in the form of the unusual conditioning procedure, promotes further learning and exploration of newly encountered stimuli, thus maximizing the possibility of acquiring reward. Chapter 7 presents a final experiment, which explored the neural correlates of appetitive conditioning in a single trial. Again, conditioning was evident based on subjective evaluations. Tentative evidence suggested a potential role for the right superior frontal gyrus in enhancing inhibitory control in response to passive viewing of cues signalling no reward. Brain activity in areas related to salience attribution was greater for a reward-paired cue presented briefly in an EBA paradigm. Although, evidence for reward-driven attentional capture was absent at a behavioural level. Overall, this thesis supports the utility of a novel naturalistic conditioning paradigm for studying appetitive conditioning processes in a single trial. Just one experience with a novel edible object transformed it into a highly desirable, craved cue. Potential applications of these findings for informing treatment and interventions for obesity and eating disorders, as well as methodological considerations and limitations are discussed in chapter 8.
| Item Type: | Thesis (PhD) |
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| Divisions: | Faculty of Health and Life Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 08 Jun 2020 13:14 |
| Last Modified: | 18 Jan 2023 23:53 |
| DOI: | 10.17638/03084482 |
| Supervisors: |
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| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3084482 |
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