only marginally significantp = 0.066
The improvement of the model fit due to the inclusion of the quadratic term was not significant for the verbal Stroop effect (Δ F (1,284) = 1.95, corrected p = 0.327) and only marginally significant for the spatial one (Δ F (1,284) = 4.57, corrected p = 0.066), but the increase in R 2 was negligible in both cases (respectively, <0.01 and 0.02).