There are two alternative explanations of the Stroop phenomenon. Several studies have revealed that the difference in performance on congruent and incongruent trials can arise from response interference. On the contrary, many authors have claimed that Stroop interference might occur at earlier processing stages related to semantic or conceptual encoding. The present study aims to determine the number and nature of the factors necessary to account for the multiple components of Stroop interference.
The sample consisted of 247 undergraduate and postgraduate students. We employed the computerized version of the Stroop task adapted to the Iranian population. An exploratory principal components analysis was conducted on the correlations of 6 variables (reaction time under congruent and incongruent conditions, omission error under congruent and incongruent conditions, and commission error under congruent and incongruent conditions).
Two factors were extracted. The first factor may be semantic interference, and the second factor may be response interference.
The findings of this research are consistent with the multiple-stage account, claiming that Stroop interference is because of both semantic and response interferences.