Highlighting Faculty Member Barbara Knowlton
scarusoucla
Date published: 09/19/25
My lab is focused on understanding learning and memory. Much of my work is motivated by the insight that learning is not a unitary phenomenon but consists of very different types of learning that depend on different brain systems. One interesting distinction is between types of instrumental learning- when we learn to associate an action with an outcome. On one hand, this type of learning can be goal-directed; for example, we can learn the series of turns in the route in order to arrive at our new workplace. However, over time, this route becomes habitual. We have learned to automatically take the correct turn when arriving at each intersection along the route and can follow the route without thinking. Habits are supported by associations between stimuli and responses- i.e. the intersections and the turns.
Because there is no goal represented in what has been learned, habits are performed even if the outcome is not desired. For example, you might find yourself driving along your route to work even though it is Saturday and you wanted to go to the park in the other direction. In this case you would say you made the turn “out of force of habit”. Much of our daily behavior is made of habits, such as brushing your teeth before bed, putting on a seatbelt when you get into a car, or reaching for your phone on your nightstand when you wake up. In all of these cases, habits can be performed mindlessly without deliberation. You may find yourself opening your refrigerator when you get home even if you are not hungry as you have developed that habit.
The transition from goal-directed action to habit is adaptive in that habits take less cognitive effort and can free up space for other mental activities. You can think about your plans for the day while habitually making a cup of coffee in the morning. Some habits, like putting on a seatbelt or washing your hands, are healthy, while others, like biting your nails or checking social media, may not be. Where habits are particularly dangerous is in the transition from casual use of drugs or alcohol and habitual use that may continue even when the negative consequences become severe. Obesity is also a consequence of negative habits, when unhealthy eating behavior becomes part of one’s routine.
We have been interested in factors that tip the balance between goal-directed actions and habits. In particular, we have been investigating the idea that experiencing early-life adversity, such as losing a parent or being neglected as a child, can affect this balance in adulthood. We have shown that individuals who report experiencing early-life adversity learn instrumental learning tasks as habits in that they continue to perform the learned response even when the outcome is no longer desired. This propensity towards habitual behavior may underlie the well-documented association between substance use and obesity in people who experienced significant early-life stress. Stress during development may subtly change the interplay between brain systems that support goal directed and habitual behavior in the corticostriatal system. Understanding this consequence of early-life adversity could focus treatment on replacing unhealthy habits with healthy ones.
I grew up in Oakland but went away to college at Johns Hopkins where I first became interested in research. I was happy to come back to California for grad school- I went to Stanford for my PhD in Neuroscience where I studied neural mechanisms of Pavlovian conditioning followed by a post-doc in the Psychiatry department at UCSD where I studied implicit learning in patients with amnesia. I have been at UCLA for my whole career as a professor. I enjoy the beaches and mountains of the LA area and visiting coffee shops on the Westside.
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