Half a century of research on the Stroop effect: An integrative review.

Abstract

The literature on interference in the Stroop Color-Word Task, covering over 50 years and some 400 studies, is organized and reviewed. In so doing, a set of 18 reliable empirical findings is isolated that must be captured by any successful theory of the Stroop effect. Existing theoretical positions are summarized and evaluated in view of this critical evidence and the 2 major candidate theories—rel-ative speed of processing and automaticity of reading—are found to be wanting. It is concluded that recent theories placing the explanatory weight on parallel processing of the irrelevant and the relevant dimensions are likely to be more successful than are earlier theories attempting to locate a single bottleneck in attention. In 1935, J. R. Stroop published his landmark article on atten-tion and interference, an article more influential now than it was then. Why has the Stroop task continued to fascinate us? Perhaps the task is seen as tapping into the primitive operations of cognition, offering clues to the fundamental process of atten-tion. Perhaps the robustness of the phenomenon provides a special challenge to decipher. Together these are powerful at-tractions in a field of complex phenomena where the most sub-tle variation may exert a dramatic effect. In writing this article, I have two primary intentions. The first is to create a taxonomy of the empirical work on the Stroop task and its analogs. At least 70% of the more than 700 Stroop-related articles in the literature have been published since the reviews by Dyer (1973c) and Jensen and Rohwer (1966). Further-more, Dyer's theoretical framework now seems in need of re-consideration, so that his review no longer provides the optimal organization. The second aim, then, is to survey existing the-ories, showing the critical weaknesses in the standard explana-tions and dispelling some myths that have arisen. I argue for a new theoretical framework for the Stroop effect, informed by contemporary cognitive psychology. This framework is more comprehensive than many earlier experiment-specific hypothe-ses, and suggests directions in which future research might profitably proceed.