Individual differences in Stroop dilution: tests of the attention-capture hypothesis.

Kahneman and Chajczyk (1983) found that naming a colored bar was slowed when a color word was nearby but that this decrement was reduced when a neutral word was also present. This has been referred to as the dilution effect. They accounted for their results with an attention-capture hypothesis. Response time distributions to stimuli that contained a color word and a neutral word within individuals were examined. The dilution effect did not appear within individuals. Some individuals exhibited strong Stroop interference effects, whereas others exhibited no interference. Experiment 2 showed that the interference pattern within individuals was consistent across days. Experiment 3 showed that performance could not be explained by a selection strategy that was based on word length. These experiments showed that performance in a color-plus-neutral word condition reflects a systematic pattern of interference or noninterference that varies across individuals.