From outcomes to actions: Fundamental mechanisms in reward seeking

How much insight do we possess about our own behavior? To what extent is it driven by the desire to achieve certain goals and to what extent is it habitual, driven by contexts and stimuli in the environment? This dissertation outlines research examining how the associations between stimuli, responses and outcomes guide and control appetitive behavior, directed towards food and drug rewards. In Chapters 2 and 3 we investigate the approach bias - a behavioral tendency to be faster at approaching rather than avoiding an appetitive picture. When considering the approach bias in this dissertation we focus on the possible motivational mechanisms that could drive such a bias - is it driven by outcome expectancies, is it a habitual response, is it Pavlovian in nature or some mix of these options? During Chapters 4 - 8 attention turns to outcome-response priming and the Pavlovian-to-instrumental transfer task. We examine how environmental cues (e.g. advertisements) can elicit anticipation of (rewarding) outcomes that in turn trigger the associated behavioral response directed towards those outcomes. Specifically, we investigate and review whether this O-R priming mechanism is sensitive to changes in the motivational significance of outcomes - can reminders of a devalued outcome trigger instrumental responding for that outcome (akin to a habitual response) or is the response only elicited when the outcome is currently desired (i.e. goal-directed in nature)? The general discussion highlights limitations of the various paradigms and we frame our insights in the context of maladaptive decision-making (e.g. overconsumption of food and drug abuse).