Stroop Interference as a Function of Percentage of Congruent Items

Color-word interference in the traditional Stroop paradigm was investigated as a function of the percentages of congruent and incongruent items. Over-all color-naming times decreased with increasing percentages of congruent items. The response time function was significantly deviant from linearity, suggesting the existence of sources of interference other than just response competition. While the pattern of response times was consistent with the notion that effects of selective attention may be enhanced by inhibition of information from the irrelevant dimension of words, data for errors did not support a stronger test of the inhibition concept. Topics discussed include the insensitivity of measurements of error and relatedness to other recent Stroop experiments and theories.