The role of goal-directed processes in the causation of seemingly habitual behavior

People sometimes do not behave in line with their explicit goals or not in their best interest. Examples of such suboptimal behaviors are action slips (e.g., entering an old password), impulsive behaviors (e.g., unhealthy eating), and behaviors in psychopathological disorders (e.g., substance use and compulsions). Suboptimal behaviors frequently occur under conditions such as stress or time pressure. The research questions addressed in this dissertation are: Where does suboptimal behavior come from, and why is it more likely to occur under conditions such as stress or a lack of time? 

Traditional dual-process models explain suboptimal behavior as the result of an impaired balance between goal-directed and stimulus-driven processes. A goal-directed process involves weighing the outcomes of behavior options for goals or valued outcomes, whereas a stimulus-driven process involves only the activation of a stimulus-response link (S-R) but ignores information about outcomes. Thus, stimulus-driven processes provide an explanation for suboptimal behavior in which people do not act in line with their valued outcomes. Traditional dual-process models have a default-interventionist architecture in which stimulus-driven processes are seen as the default determinant of behavior because they are automatic whereas goal-directed processes only have a corrective role. It is then assumed that stress or time pressure reduce the available operating conditions of the system and in this way act as a switch from goal-directed to stimulus-driven processing. 

Recent work has challenged the dominant role of stimulus-driven processes in explaining suboptimal behavior. Moors et al. (2017) proposed an alternative dual-process model with a parallel-competitive architecture in which goal-directed processes can also be automatic so that they operate in parallel with stimulus-driven ones. The model, moreover, assumes that goal-directed processes often win this competition so that they are the default determinant of behavior. The authors argued that the role of goal-directed processes has so far been underestimated because several complexities tend to be overlooked. In the current dissertation, I examined four of these complexities: (a) People consider multiple outcomes, (b) one outcome can be achieved through multiple responses and the most optimal response option is not always available, (c) one response may be part of different response-outcome links, and (d) people make mistakes during learning and/or deployment of goal-directed processes or they are unable to complete them due to poor conditions. The aim of this dissertation was to test if findings that are typically seen as evidence for stimulus-driven processes can be explained in a goal-directed way if these complexities are considered. 

In Chapter 1, I introduce the traditional and the alternative dual-process model. First, I outline the theoretical assumptions of traditional dual-process models and review empirical evidence in favor of the role of stimulus-driven processes. Next, I outline the alternative dual-process model and present alternative goal-directed explanations for the above-mentioned findings. In Chapters 2-5, I report five studies in which these alternative explanations were empirically tested. Finally, in Chapter 6, I provide a summary of the key findings, discuss theoretical and practical implications, address limitations, and offer avenues for future research.