The article by J. Ridley Stroop, published in the *Journal of Experimental Psychology*, explores the concept of interference in serial verbal reactions. The study builds on previous research by physiologists and psychologists who have investigated the inhibitory effects of changing habits and associations. Stroop's work focuses on the interference caused by conflicting stimuli, such as words and colors, in verbal tasks. In the first experiment, Stroop examines the effect of color stimuli on the time taken to read color names. The results show that reading color names printed in different colors from those named by the words took an average of 2.3 seconds longer, but this difference was not reliable. In the second experiment, the focus shifts to the effect of word stimuli on the time taken to name colors. The results indicate that naming colors in the presence of conflicting word stimuli increased reaction time by 74%, suggesting a strong interference effect. The third experiment investigates the impact of practice on interference. Practice on the conflicting word stimuli test (NCWd) decreased the interference effect but did not eliminate it. Practice also increased individual differences in performance, particularly on the NCWd test, where the interference was more pronounced. The study concludes that the interference effect is due to the strength of the associations formed through training, with word stimuli being more effective in inhibiting color naming responses than vice versa. Overall, the study provides insights into the nature of interference in serial verbal reactions and suggests that the differences in speed between reading color names and naming colors can be attributed to the varying levels of training in these activities.The article by J. Ridley Stroop, published in the *Journal of Experimental Psychology*, explores the concept of interference in serial verbal reactions. The study builds on previous research by physiologists and psychologists who have investigated the inhibitory effects of changing habits and associations. Stroop's work focuses on the interference caused by conflicting stimuli, such as words and colors, in verbal tasks. In the first experiment, Stroop examines the effect of color stimuli on the time taken to read color names. The results show that reading color names printed in different colors from those named by the words took an average of 2.3 seconds longer, but this difference was not reliable. In the second experiment, the focus shifts to the effect of word stimuli on the time taken to name colors. The results indicate that naming colors in the presence of conflicting word stimuli increased reaction time by 74%, suggesting a strong interference effect. The third experiment investigates the impact of practice on interference. Practice on the conflicting word stimuli test (NCWd) decreased the interference effect but did not eliminate it. Practice also increased individual differences in performance, particularly on the NCWd test, where the interference was more pronounced. The study concludes that the interference effect is due to the strength of the associations formed through training, with word stimuli being more effective in inhibiting color naming responses than vice versa. Overall, the study provides insights into the nature of interference in serial verbal reactions and suggests that the differences in speed between reading color names and naming colors can be attributed to the varying levels of training in these activities.