I am a third year PhD student at the University of Sheffield, where I am supervised by Professor Matt Field and Dr Tom Stafford. Although based in the Department of Psychology, I also work alongside the Sheffield Alcohol Research Group in Sheffield’s School of Health and Related Research. In my PhD I am exploring the potential mechanisms that underlie behaviour change and recovery from addiction using computational models of value-based decision-making. Before starting my PhD, I obtained a BSc and MSc in Psychology from the University of Liverpool.
Modelling value-based decision-making in regular alcohol consumers after experimental manipulation of the value of alcohol
Aim: Harmful alcohol consumption and dependence is characterised by hypervaluation of alcohol and hypovaluation of non-alcohol alternatives. This is the first study to manipulate the value of alcohol and apply a computational model of value-based decision-making (VBDM) to parameterise the internal processes of decision-making.
Methods: Using a within-subject design, 36 alcohol consumers were primed to ‘value’ and ‘devalue’ alcohol by watching videos that emphasised the positive versus the negative consequences of alcohol consumption. After being primed, participants completed a two-alternative forced choice task in which they chose between either two alcohol images (in one block) or two soft drink images (in a different block). On each block, participants pressed a key to select the drink image that they would rather consume. We applied a drift diffusion model (DDM) to the reaction time and accuracy data to estimate evidence accumulation (EA) processes and response thresholds during the different blocks.
Results: After devaluation of alcohol, soft drink EA rates were significantly increased compared to alcohol EA rates (‘p’=.035, ‘d’=.31) and compared to soft drink EA rates when participants were primed to value alcohol (‘p’=.015, ‘d’=.38). However, the experimental manipulation had no effect on EA rates for alcoholic drinks or on response thresholds in either priming condition.
Conclusions: Devaluation of alcohol results in amplified EA rates for soft drinks compared to alcoholic drinks. Surprisingly, the experimental manipulation of alcohol value only altered the internal processes that precede decision-making for soft drinks rather than alcoholic drinks.