Important decisions are often made under stressful circumstances that might compromise self-regulatory behavior. Yet the neural mechanisms by which stress influences self-control choices are unclear. We investigated these mechanisms in human participants who faced self-control dilemmas over food reward while undergoing fMRI following stress. We found that stress increased the influence of immediately rewarding taste attributes on choice and reduced self-control. This choice pattern was accompanied by increased functional connectivity between ventromedial prefrontal cortex (vmPFC) and amygdala and striatal regions encoding tastiness. Furthermore, stress was associated with reduced connectivity between the vmPFC and dorsolateral prefrontal cortex regions linked to self-control success. Notably, alterations in connectivity pathways could be dissociated by their differential relationships with cortisol and perceived stress. Our results indicate that stress may compromise self-control decisions by both enhancing the impact of immediately rewarding attributes and reducing the efficacy of regions promoting behaviors that are consistent with long-term goals.

Health nudge interventions to steer people into healthier lifestyles are increasingly applied by governments worldwide, and it is natural to look to such approaches to improve health by altering what people choose to eat. However, to produce policy recommendations that are likely to be effective, we need to be able to make valid predictions about the consequences of proposed interventions, and for this, we need a better understanding of the determinants of food choice. These determinants include dietary components (e.g. highly palatable foods and alcohol), but also diverse cultural and social pressures, cognitive-affective factors (perceived stress, health attitude, anxiety and depression), and familial, genetic and epigenetic influences on personality characteristics. In addition, our choices are influenced by an array of physiological mechanisms, including signals to the brain from the gastrointestinal tract and adipose tissue, which affect not only our hunger and satiety but also our motivation to eat particular nutrients, and the reward we experience from eating. Thus, to develop the evidence base necessary for effective policies, we need to build bridges across different levels of knowledge and understanding. This requires experimental models that can fill in the gaps in our understanding that are needed to inform policy, translational models that connect mechanistic understanding from laboratory studies to the real life human condition, and formal models that encapsulate scientific knowledge from diverse disciplines, and which embed understanding in a way that enables policy-relevant predictions to be made. Here we review recent developments in these areas.

Rewards usually have multiple attributes that are relevant for behaviour. For instance, even apparently simple choices between liquid or food rewards involve comparisons of at least two attributes, flavour and amount. Thus, in order to make the best choice, an organism will need to take multiple attributes into account. Theories and models of decision making usually focus on how strongly different attributes are weighted in choice, e.g., as a function of their importance or salience to the decision-maker. However, when different attributes impact on the decision process is a question that has received far less attention. Although one may intuitively assume a systematic relationship between the weighting strength and the timing with which different attributes impact on the final choice, this relationship is untested. Here, we investigate whether attribute timing has a unique influence on decision making using a time-varying drift diffusion model (tDDM) and data from four separate experiments. Contrary to expectations, we find only a modest correlation between how strongly and how quickly reward attributes impact on choice. Experimental manipulations of attention and neural activity demonstrate that we can dissociate at the cognitive and neural levels the processes that determine the relative weighting strength and timing of attribute consideration. Our findings demonstrate that processes determining either the weighting strengths or the timing of attributes in decision making can adapt independently to changes in the environment or goals. Moreover, they show that a tDDM incorporating separable influences of these two sets of processes on choice improves understanding and predictions of individual differences in decision behaviour..