EEG Study of 38 People Finds Brain Wave Tracks Learned Rules 2 Degrees From Boundary
Updated
Updated · PsyPost · Aug 14
EEG Study of 38 People Finds Brain Wave Tracks Learned Rules 2 Degrees From Boundary
2 articles · Updated · PsyPost · Aug 14
Summary
University of Nevada, Reno researchers found a decision-linked EEG signal rose and peaked as volunteers classified images using arbitrary rules they had just learned, extending a mechanism previously tied mainly to sensory evidence.
Data from 38 participants showed choices got faster and more accurate as line angles moved farther from each person’s hidden category boundary—from just 2 degrees away to 45 degrees away.
A drift-diffusion model showed evidence accumulated faster when stimuli were farther from the learned boundary, and the centro-parietal positivity signal steepened in parallel across participants.
Motor-cortex beta activity changed with button preparation but not with task difficulty, supporting the conclusion that the key signal reflects deciding rather than merely moving.
The authors said the task used a simple one-dimensional visual rule with a hard cutoff, so testing whether the same mechanism handles messier real-world categories remains for future work.