Evaluation of Dual-Process Models in Decision Making : Suppression of Irrelevant Activation in Conflict Paradigms

Abstract

We deal with conflict response tendencies on a daily basis and succeed to resolve this conflict most of the times. When we fail, however, this can result in dangerous situations, for instance driving a car in a difficult traffic situation. Cognitive control processes, such as the filtering of irrelevant information and the suppression of irrelevant response activations are needed to overcome impulsive responses. To investigate cognitive control processes in the lab, congruency paradigms such as the Simon (Simon & Rudell, 1967), the Eriksen flanker (B. A. Eriksen & Eriksen, 1974), and the Stroop task (Stroop, 1935) have been developed. What these paradigms have in common is the presence of two stimulus dimensions, one which is relevant to the task and the other which is task irrelevant. While the participant is supposed to respond to the relevant stimulus dimension, for instance the color or shape of the stimulus, he or she has to ignore the task irrelevant stimulus dimension. However, the difficulty in the tasks is that the irrelevant dimension also corresponds to a response, and thus, a response selection conflict arises. Interestingly, albeit the similarities between the tasks, previous research has provided evidence that the involved cognitive control processes differ between the tasks. Whereas filtering of the irrelevant stimulus dimension seems to be relevant in all tasks, suppression of irrelevant response activation is usually observed in one particular version of the Simon task only. This raises the question of how important the suppression of irrelevant activation is in our daily lives. The current work investigates suppression of irrelevant activation in different congruency paradigms. Study 1 demonstrates that suppression of irrelevant activation occurs at least in one more version of the Simon task, and thus, broadens the relevance of suppression of irrelevant activation. The second study indicates that suppression of irrelevant activation can also occur in the flanker task. Further it reveals the dependency of suppression of irrelevant activation on the timing of the presentation of the task relevant and the task irrelevant information. Suppression of irrelevant activation increases when the task irrelevant information is provided earlier. In Study 3 it is examined why suppression of irrelevant activation is hardly present in the flanker task when task relevant and task irrelevant information are provided simultaneously. The results show that participants cannot differentiate between the automatic response activation driven by the target and by the flanker easily, and thus, cannot selectively suppress the irrelevant activation. Together, the results of the studies demonstrate that suppression of irrelevant activation is a useful cognitive control process that is most likely highly relevant and often used in our daily lives.