research

The main focus of my postdoctoral work is motivation in the context of reinforcement learning. My recent projects include computational modeling of clinical data during learning tasks, building computational models of behavior and value, and investigating the neural representation of symbolic reinforcement (e.g. tokens) versus rewards.

Current & recent projects

Reinforcement learning

Reinforcement learning (RL) is a theoretical framework that describes how agents learn to select options that maximize rewards and minimize punishments over time.

How does uncertainty of reward affect impulsive choice behavior? (Burk & Averbeck, 2023)

Symbolic reinforcement

We often make choices to obtain symbolic reinforcers (e.g. money, points, tokens, tickets) that can later be exchanged for primary reinforcers (e.g. food, drink). Although symbolic reinforcers are highly motivating, little is understood about the computational and behavioral mechanisms that shape this motivation. We are working on some key questions in this domain:

How do more and less preferred rewards affect motivation when offered jointly?
How is representation of multiple symbolic reinforcers relative?
How do rewards and symbolic rewards affect motivation during learning? (Burk et al., 2024)

Neural representation

We are interested in the neural representation of learning processes during reinforcement learning tasks. We use a multi-site, multi-probe recording strategy to record neural activity from a range of deep structures shown to be involved in learning.

Computational psychiatry

There has been a recent focus on using computational methods, behavior, and clinical data together to predict symptom severity and treatment outcomes for a range of clinical disorders (Huys et al., 2016). We have been collaborating with clinical labs to use reinforcement learning models to relate behavior to clinical metrics in various ways:

Can reinforcement learning tasks used in the lab predict longitudinal self-reports anxiety? (Fullana lab, Barcelona)
Can lab-induced frustration and pediatric irritability be related to learning rates? (Leibenluft lab, NIH)
How does brain structure relate to safety learning and anxiety? (Abend, Burk et al., 2022)