Habits as hierarchical building blocks

University Of California Berkeley, Berkeley CA

Investigators

Abstract

Project Summary/Abstract Habits make up an essential part of humans' everyday behavior. Habits enable us to perform routine activities, such as driving to work, in an automated, effortless way, freeing up our cognitive resources for more effortful concomitant tasks, such as conversing with our passenger. Successfully establishing good habits, such as regular hand washing, sleep times, or exercise, is essential for a healthy lifestyle. However, because they are automated and inflexible, habits can also lead us astray, causing us to inadvertently drive to work when we meant to go to the doctor or eat snacks when we're not hungry, and in extreme cases, promoting drug seeking behavior and addiction. Overcoming habits when they are not appropriate for our current goal requires goal-directed control. While the balance between habits and goal-directed control has been well-studied in non-human animals, cognitive neuroscientists have struggled to translate the standard approaches in this domain into human ex- perimental research. Specifically, humans are more efficient than non-human animals at exerting control that overrides habits, making it difficult to reveal habits in lab experiments, even after thousands of training trials. Furthermore, it has proven difficult to attribute habit-like behavioral patterns (such as “slips of action” like go- ing to work instead of going to the doctor) to the strength of the habit, as opposed to the weakness of control processes. This project will develop a new human protocol that will allow researchers to 1) induce habits in hundreds of trials, making it a practical, single-session task for future research, 2) disengage control enough to reveal habit behavior, and 3) reveal engagement of control in a way that is separable from the strength of habit expression. To do so, our approach steps away from successful rodent task designs, and instead relies on the insight that human decision-making is hierarchical. Specifically, we will leverage the hypothesis that humans make more abstract choices (e.g. driving, vs. walking to work) in a controlled, goal-engaged way, then naturally disengage control and execute their high-level decision with habitual routines. Aim 1 will develop and test the validity of the protocol with regards to the three targets above; aim 2 will directly test the role of hierarchical decision-making in expressing habits. If successful, this project will open the doors to a wealth of downstream research on habits and goal-directed decision-making, including probing their neural substrates in functional imaging, and their role in individual dif- ferences and clinical conditions. If someone is unusually prone to habit-like mistakes (e.g. finding themselves at work when planning to go to the doctor), it is currently difficult to attribute this to strong habit expression as opposed to weak control. Our protocol will enable us to pull this apart, with important implications for the study of psychiatric conditions such as obsessive-compulsive disorder, eating disorders, and addiction.