Stroop Effect: Conflict Detection and Control Strategy Factors

Abstract

Three experiments (N = 190) were conducted to study the effect of control strategy on the strength of interference in a reverse Stroop task. The participants were asked to determine as quickly as possible the meanings of incongruent words (for example, the word “red” printed in blue) and to ignore the color of the text. Responses were registered using the “up”, “down”, “left” and “right” arrow keys on the keyboard. Colored squares were used to assign keys to responses in the current trial. For example, if the red square was in the top part of the picture, the participant had to press the “up” button in order to response “red”. In the “conflict” stimuli, a square of the same color as the word was presented; in the control stimuli, there was no corresponding square. The color-meaning combinations were identical in both “conflict” and control stimuli. A significant difference in response times for conflict and non-conflict stimuli was only observed when 1) they were presented in separate blocks, or 2) the colored squares were presented before the word. This difference decreases significantly if the conflict stimuli are presented as a separate block after the block of control stimuli and if the block of control stimuli is presented after the conflict stimuli. The effect of cognitive control strategy and conflict detection on the efficiency of solution of interference tasks is discussed.