A neuroeconomic investigation of risky decision-making and loss in the rat

Abstract

Humans exhibit a number of suboptimal behaviours in the wake of a loss. For example, gamblers often ‘chase’ their losses in an attempt to break even. Similarly, investors tend to hold on to losing stocks too long in the hope that the declining share price might make a recovery. However, the neural mechanisms that instantiate such behaviour are poorly understood. I begin the introductory chapter with a basic historical overview of fundamental economic concepts, interleaving intersecting ideas from psychology and neuroscience. This leads to a more in-depth exploration of the notion that loss-related behavioural biases might provide insight into the neural mechanisms that underlie risky choice. From this, I argue that rats represent a viable animal model of risky decision- making for neuroeconomic research. The original research presented in Chapters 2 – 5 pave the way toward advancing our current understanding of loss-related biases in behaviour with rat models of risky decision-making. By employing insight from psychology and economics, I developed two models of rat behaviour that can be used to study the neural substrates of loss valuation. I presented the experimental paradigms in Chapters 2 and 5, while demonstrating novel loss-related correlations between the midbrain dopamine system and observed loss behaviour in Chapters 3 and 4. The results presented in Chapter 5 demonstrate that rats are capable of producing behavioural patterns akin to loss aversion and the disposition effect. This work has also highlighted a number of areas for future research. In Chapter 6, I explore potential theoretical implications of the results discussed in previous chapters. In summary, this thesis uses experimental risky decision-making tasks in rats to advance our current knowledge of the ways in which concepts such as loss aversion critically influence our internal representation of value.