The Stroop Effect has been widely researched. It explains how a cognitive process might interfere with another cognitive process (MacLeod, 1991). This effect works because associations already made in the brain inhibit recall abilities for new associations (Stroop, 1935). The Stroop Effect is relevant because it can explain what cognitive processes are automatic compared to controlled processes. An automatic process is naturally fast and does not need conscious attention to be accomplished, and controlled processes are slower and do require cognitive attention (Cohen, 1990).
Some cognitive processing functions require more energy and application than other processing functions (MacLeod, 1991). This could be beneficial knowledge in improving teaching techniques and provides information on inhibition and cognitive ability. There are many different ways to test the Stroop Effect. A common experiment is having someone state the color of the word rather than read the text of the word (Cohen, 1990). In this experiment, the automatic process of reading the color of the word interferes with stating the color of the ink used to present the word (Cohen, 1990).
While the previously mentioned experiment is most common, there are other ways to test and study the Stroop Effect. An experiment done by Constantine and colleagues used pictures and fear response to test the Stroop Effect. This experiment tested how the automatic process of a fear response can interfere with a controlled cognition, such as color identification, by presenting pictures of snakes, bunnies, and cows (Constantine et al, 2001).
The snakes were used to elicit a negative emotional response, the bunnies were used to elicit a positive emotional response, and cows were used as a neutral control stimulus (Constantine et al, 2001). Stroop Effect experiments typically test for reaction times to words or pictures to conclude if the data suggests there is interference (Lindsay & Jacoby, 1994). There has been some debate to determine if it is more accurate to collect data from reaction time instead of the accuracy of answers from participants.
In one experiment, researchers measured the Stroop effect the standard way by measuring reaction time and then measured the Stroop effect by measuring the accuracy of responses (Lindsay & Jacoby, 1994). Reaction time might not accurately represent the findings because in the present study, participants were asked to count the number of words on a page while also reading written number words. How accurate the person states how many words are written on the presentation page might provide more reliable data than their reaction time.
For this experiment, however, reaction time is what will be recorded. It is hypothesized that the participant response time will be slower when the written number is incongruent with the amount of numbers presented on the screen because the automatic process of reading the number word is expected to interfere with the controlled task of counting the number words. Method Participants The population studied is Indiana University undergraduate students, between the ages of 18-22. The sample included in the present study consisted of eight participants, five male and three female.
There were three freshman, two sophomores, two juniors, and one senior in this sample. All participants in the study were predominately white. The resampling used data collected from these participants. Materials The experiment was done by presenting two different PowerPoint presentations to each participant. One presentation was used as the control. This presentation consisted of written number words presented as many times as would be congruent with the written number word. For example, the number two was written two times.
The second presentation was used to test interference in cognition between the automatic process of reading and the controlled process of counting the number of words displayed on the screen. Written numbers in this presentation were incongruent with the number of times the number words were presented. For example, the word five was written three times. Each PowerPoint had a slide labeled “press enter to start” so that the instructor could explain the procedure to the participant. Each presentation also had 20 slides of written numbers on them.
The rehearse timing mode in PowerPoint was used to record how much time a participant spent on each slide. In order to account for the first slide in which the experimenter explained the procedure, the time spent by the participant when actively engaged in the experiment was equal to the total time minus the time on the first slide. Procedure The participants were asked to sit down with the PowerPoint presentation in front of them. Their task was to count how many words were on the screen and say that number out loud before clicking to the next screen.
Once participants finished the first PowerPoint, they waited while the instructor prepared the next PowerPoint and repeated the process. In order to make sure the data was reliable, half of the participants were given the control presentation first and the other half were given the interference presentation first. This was to counterbalance the effect that one presentation might have if given first every time. Results This experiment was designed to compare how quickly participants were able to count words when there is interference and when there is no interference.
The average time for the interference presentation was 25. 1 seconds, compared to the average time for the control presentation (23. 4 seconds). The maximum time spent on the interference presentation was 36 seconds, and the minimum time spent on the interference presentation was 20 seconds. For the control presentation, the maximum time spent was 31 seconds and the minimum time spent was 20 seconds. Since the sample size was very small, the data was resampled using a java applet. This generated representative data, as if the sample size was 10,000 students.
With a Confidence Interval of 95%, zero was not included, which suggests that there is a significant difference between interference of counting and reading words (Figure 1. 1). The p value was 0. 0004 and the Confidence Interval was 0. 75 and 2. 875. These suggest that the data is very significant. Figure 1. 1 Discussion In this study, it was hypothesized that response time would be slower when participants were asked to count the number of words written on the page that was incongruent with the written number.
The results from the experiment suggest that the response time was indeed slower when there is interference in cognitive processes. In general, the participants’ response time was slower for the interference presentation than their response time for the control presentation. Knowledge of how interference works in the human brain can lead to better teaching techniques and can be used in several areas of business, such as marketing. There are some issues that need to be addressed with this experiment.
The participants were asked to say out loud how many words were on the page. This may have impacted their response time by having to process the word, then count how many words there are, and finally speak that number. It may have not impacted their time significantly but it could possibly be a confounding factor. The population that this experiment was directed at could also present another issue. It was directed towards college students at Indiana University. However, the participants’ age was limited to the typical age of a college student and excluded older students.
Therefore, this data will not be generalizable to all Indiana University students. In the future, including a larger population size, like all college students, could provide useful information in how cognition works between automatic and procedural processes. Cognitive processing in the human brain is something many psychologists study in hopes of better understanding human behavior and expanding human knowledge. This experiment was designed to help further this knowledge of cognitive interference.
