Two forms of the Stroop test.

16 subjects performed a conventional chart-form and a card-sorting form of the Stroop color-word interference test. Interference scores on the two forms were positively and significantly correlated, while neither word reading nor color naming scores showed a significant correlation. It is suggested that the 'Stroop effect' has some, but limited, generality and that forms not requiring verbal response may be more useful than the traditional chart version in providing a general measure of interference proneness.