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Abstract

In intertemporal choice the subjective value of a reward decreases as the delay until its receipt increases, a phenomenon known as delay discounting. Discounting rates vary substantially across individuals, and demographic correlates only explain a small proportion of the variability. This thesis explores potential reasons for differences in discounting across individuals by looking at whether they may be more driven by differences in the underlying representation of the options under consideration or processes by which decisions are made.

The first strand explored the relationship between delay discounting and two key phenomena linked to the way the future is represented in mind: Temporal construal, where delay qualitatively affects the way an event is represented, and episodic future thinking (EFT; the ability to project oneself through time to pre-experience a future outcome). Although variability across individuals in all three measures – discounting, construal and EFT – was substantial, associations among the three constructs were weak, suggesting differences in discounting are not mediated by differences in the other variables.

The second strand used eye tracking to investigate processes underlying discounting, by examining the frequency of transitions between different attributes in discounting choice options. Participants made a fairly even combination of within-attribute and within-option transitions, suggesting a mixed strategy for evaluating options. More within-attribute transitions generally predicted less discounting.

The strands also examined potential mechanisms for two manipulations known to affect discounting: The delay-date effect, where describing future rewards using dates rather than delays reduces discounting; and episodic tagging, where adding a participant-specific episodic cue to future outcomes similarly reduces discounting. Despite behavioural similarities, eye movements patterns differed, with more within-attribute transitions for dates than tags.

Overall, the findings help rule out some plausible representational and process-driven accounts for individual differences in delay discounting and provide insights into some of the general features that underlie intertemporal choice.

Publication Type:	Thesis (Doctoral)
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Departments:	Doctoral Theses School of Health & Psychological Sciences > Psychology School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses

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