Descriptions and Features of Stroop Effect

Cognitive control is the process that is used to overpower dominant responses in favor of less appealing ones. One way to measure this is through Stroop tasks. Stroop tasks measures the ability to respond to certain environmental stimuli while ignoring others. The Stroop effect is degree of difficulty people have when performing the task, such as naming the color of the ink rather than the word itself. There is an interference between the color of the ink and the word’s meaning. This interference happens no matter what, making it an uncontrollable part of conscious.

In 1935, J.R. Stroop had released an article on attention and interference (MacLeod, 1991). Stroop had tested the effect of ink colors that were not the same as the name. In his experiments, he first concluded that words had a single response while colors had multiple responses. While he did was the first to observe the Stroop interference, there were slight limitations about his work. He never had congruent condition to compare his results to and his article never mentioned automaticity, although it did hint at it. There have been numerous experiments conducted and articles published since then explaining this phenomenon under different conditions and concluding new findings. Mackinnon, Geiselman, Woodward (1985) concluded that Stroop interference could be reduced during the process of the word meaning. Huguet, Galvaing, Monteil and Dumas (1999) concluded from their experiment that another person’s presence during the task also reduced the Stroop effect. James D. Windes (1958) wanted to test whether different kinds of Stroop tests would effect the reaction time, such as numerical Stroop tasks or symbol Stroop tasks. He highlighted from previous studies that the object must be recognized for the brain to process and identify, in which the procedure for identifying and naming responses may or may not be difference. His results showed that there was a difference in the two different Stroop tasks, which lead to his discovery that there might be different possibilities for delay in naming a color or word: identification task conflict and response conflict (Windes, 1958). In a different study, different conditions of the same color Stroop task were tested (Hintzman et al., 1972). This study showed that there was difference in the normal color Stroop set (the color of the ink was on of the other three colors named) and the three other Stroop sets.

However, in two of the word sets, there was no significant difference, supporting the statement that there isn’t an effect of neutral words on color Stroop tasks. The last set also proved that if the word started with same letter as the ink color, the response time was faster (Hintzman et al., 1972). The compatibility of the stimulus that are relevant and irrelevant affect the reaction time of the completion: if the Stroop task is congruent, then the reaction time might be faster (facilitation) and if the Stroop task is incongruent, then the reaction time might be slower (interference) (Scuzs and Soltész, 2007). Scuzs and Soltész concluded from their experiment that interference during response was related to processing the context the words/color were in. There wasn’t enough data to make a conclusion on whether numerical and size information are different when processing in facilitation and interference (2007). In another experiment under different conditions, Besner, Stolz, and Boutilier (1997) supported that coloring a single letter differently from the rest of the word reduced the reaction time for the participant and thus reducing the Stroop effect. This meant that a considerable amount of the semantic processing was locally controlled by the elements of the task. Kadosh, Gevers, and Notebaert (2011) suggested that automatic activation of irrelevant subjects was suppressed at the response level, which highlighted the interaction between numerical magnitude and physical size as the effect of differing responses and stimuli on automatic processing.