A joint additive model made the mean early FCz error contrast less negative in 26 ERP CORE flanker recordings

We tested stimulus overlap in a fixed early FCz error score from public ERP CORE flanker EEG. The primary analysis included 26 of 40 people, with 756 errors and 5,579 correct trials. Under an additive event model, adding four stimulus functions shifted the mean error contrast by +0.909 microvolts. The 95 percent person bootstrap interval was +0.297 to +1.531 microvolts. The joint contrast was -4.984 microvolts. All six planned checks gave the same direction of change. The median joint-to-response design variance ratio was 1.201 under independent unit sample errors. Fixed category functions, finite time supports, artifact selection, and one cohort limit the interpretation. Two complete offline analyses matched exactly. The package contains continuous FCz for all 40 people, source hashes, retrieval recipes, trial decisions, code, fits, and bootstrap draws. It also contains the fixed local plan, validation reports, and reproduction commands.

event-related potentials · EEG · error-related negativity · flanker task · regression with overlapping events · additive models · stimulus overlap