The Stroop effect: It is not the robust phenomenon that you have thought it to be

Five experiments demonstrate that context has a powerful effect on the ease with which people can name (Experiments 1-3) or categorize (Experiments 4- 5) a stimulus while ignoring another stimulus, irrelevant or conflicting wi th the target. Selectivity of attention to the target dimension was gauged through Stroop and Garner effects. When the stimulus values along the targe t dimension and the to-be-ignored dimension were correlated over the experi mental trials, large effects of Stroop and Garner influenced performance. H owever, when random allocation of values created zero dimensional correlati on, the Stroop effects vanished. These results imply that when the nominall y irrelevant dimension is in fact correlated with the relevant dimension, p articipants then attend to the irrelevant dimension and thus open themselve s up to Stroop interference. Another variable of context, the relative sali ence of the constituent dimensions, also affected performance with the more discriminable dimension disrupting selective attention to the less discrim inable dimension. The results demonstrate the importance of context in enge ndering the failure of selective attention and challenge traditional automa ticity accounts of the Stroop effect.