An important objective of animal welfare science is the development of indicators of putative subjective emotional (affective) states. To this end, Paul et al (2005) have proposed devising animal-based measures sensitive to changes in certain cognitive processes found to be biased in characteristic ways across affective state in humans. This thesis investigates the application of this approach. The first three experimental chapters examine judgements of ambiguous stimuli in rodents. In the first two of these studies, it was hypothesised that a treatment designed to induce a positive, or negative, change in affect would be associated with a higher, or lower, probability (respectively) of responding to ambiguous stimuli in a manner in keeping with a bias towards optimism; such biases, across affect, have been found in humans. These hypotheses were not supported, at least not in simple terms, with the results revealing counter-intuitive treatment effects, and variation in response accuracy and efficiency. In the last of these three experimental chapters, we applied a treatment designed to induce a change in food motivation. This altered rats' operant responses in a manner suggesting their behaviour was a least partly goal-directed, and also suggesting that the possibility of motivation-related confounds, when studying responses to ambiguity, was real. The final experimental chapter investigated affect-related biases in the foraging behaviour of domestic chicks. We hypothesised that chicks undergoing a treatment designed to induce a negative change in affect would attack fewer red crumbs (a colour commonly associated with aposematism), and more green crumbs, than a control group. We found the opposite: i. e. the former treatment group attacked significantly more red crumbs. This curious finding was reconciled with reference to the functional architecture of the attentional processes implicated in foraging behaviour. In the final chapter, the implications of these, and related, findings are discussed
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:499747 |
| Date | January 2008 |
| Creators | Parker, Richard Munro Aubury |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1983/f1664bcf-1826-4bb5-a99b-3665cf5bfb80 |
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