Projects
Current research
Effort, rest, and task switching
I designed and built online experiments that investigate how self-paced rest decisions (a potential proxy for cognitive fatigue), task switching, and performance in an effortful task interact. Using a combination of mixed effects modeling, machine learning, and time-varying hidden Markov modeling, I'm developing computational models of how task switching interacts with latent cognitive states.
Key findings: People's self-paced rest decisions are stable but do little to aid recovery (CCN 2026, extended abstract). Results also suggest that switching tasks while performing poorly may benefit later performance (CCN 2025, extended abstract). First-author paper in prep: Task-Switching Resets Latent Performance States During Cognitive Effort.
Controlling your own learning with AI
As more people learn with AI, it's important to know whether it builds skills or replaces them. I'm running a series of online behavioral studies on how well people can control their own learning when an AI assistant is available, and how AI assistance shapes learning outcomes and metacognitive judgments. For example: do people use the AI differently when they know they'll be tested without it later, and does using it change their sense of when they've learned enough?
How practice reshapes brain networks
Using a dense-sampling fMRI dataset where 46 participants did the same cognitive control tasks across many sessions, I'm using hyperalignment to align participants' brain responses and analyze how active brain networks shift with practice, in order to identify neural signatures of practice effects. The dataset is part of a larger lab effort toward a neural taxonomy of cognitive control (OHBM 2026).
Previous work
Classifying fMRI data from the orbitofrontal cortex
I built supervised learning models to classify cognitive states from high-dimensional orbitofrontal cortex fMRI data. I also managed data collection for neuroimaging experiments.
Evaluating CLIP on photos taken by blind and low-vision users
CLIP was trained mostly on photos taken by sighted people. I tested whether it works for blind and low-vision users, using VizWiz-Captions, a dataset of real photos they took. I built a statistical evaluation pipeline to measure CLIP's accuracy, then tried to improve its accuracy by fine-tuning a neural network classifier and adding it to the pipeline.
Simulating language conventions in emerging sign language communities
I implemented and adapted several hierarchical Bayesian models to simulate how shared linguistic conventions emerge in new sign language communities of different population sizes.
Publications
- Klevak, N., Buckholtz, J. W.#, & Poldrack, R. A.# Task-switching resets latent performance states during cognitive effort. In preparation. (#co-senior authors)
- Boyce, V., Prystawski, B., … Klevak, N., … Frank, M. C. (2025). Estimating the replicability of psychology experiments after an initial failure to replicate. Collabra: Psychology. [doi]
Conference presentations
- Klevak, N., Buckholtz, J. W., & Poldrack, R. A. (2026). Self-paced rest decisions: stable but ineffective for recovery. Extended abstract & poster, CCN 2026. Selected as a spotlight. [pdf]
- Bissett, P. G., … Klevak, N., … Poldrack, R. A. (2026). Toward a neural taxonomy of cognitive control: A dense-sampling study of 46 individuals. Poster, OHBM 2026.
- Koller, W. N., … Klevak, N., … Norman, K. A., & Niv, Y. (2026). Atypical event segmentation in schizotypy. Poster, SOBP 2026.
- Klevak, N., Buckholtz, J. W., & Poldrack, R. A. (2025). The effect of task switching on cognitive fatigue. Extended abstract & poster, CCN 2025. [pdf]
- Harootonian, S., Ho, M., Klevak, N., & Niv, Y. (2022). The best advice you can give. Contributed talk, CCN 2022 (presented by Sevan Harootonian). [doi]