Stroop-type interference: Congruity effects in color naming with typewritten responses

Four experiments examined the Stroop effect with typewritten responses. Experiment 1 compared vocal, arbitrary-keypress, and typewritten responses and found the largest Stroop effect for typewritten responses. The effect appeared in the latency to type the first keystroke and not in the duration of the typing response. Experiment 2 compared normal (name the color) and reverse (name the word) Stroop effects with typewritten responses and found that the normal Stroop effect was much larger than the reverse Stroop effect. Experiment 3 compared typing the entire color name with typing its first letter and found equivalent Stroop effects in the 2 conditions. Experiment 4 varied the relative frequency of congruent and incongruent trials and found that the typewritten Stroop effect was larger when congruent trials outnumbered incongruent trials. The results are related to theories of the Stroop effect and theories of language production.