Stroop Effect of Color Stimuli: Impact of Time for Color Memorization on Cognitive Interference

Abstract

The study aimed to investigate the effect of color memorization time on cognitive interference in the context of the Stroop experiment. The study involved 23 psychology students as participants who were subjected to color and word tests. According to the study results, the longer the duration of color memorization, the increased level of cognitive interference, causing students to repeat the reading activities. The practice experiment improved participants’ performance in memorizing the colors and reducing interference. The study findings prove the concepts of cognitive psychology in controlling cognitive interference, as identified by Stroop. Therefore, the study emphasizes factors affecting cognitive interference, and further research is required.

The color optic response is a human response to stimuli, a fundamental area of study in cognitive psychology. Besides, cognitive interference is a phenomenal aspect of this study that occurs when the human brain perceives conflicting information leading to the inefficiency of the color-involved task (Sarason et al., 2014). According to the Stroop test, cognitive interference study covers the aspect of attention, automaticity, and cognitive control while time is an essential factor. The experiment was developed in 1935, in which the respondents were engaged in an experiment involving ink color and reading. The names of the colors might have or not have matched the specific ink used in the study, creating conflicting cognitive interference. The participants in the experiment were cognitively conflicted that they suppressed their automaticity in response to reading the meaning of the words and made more errors in identifying the colors (Stroop, 1935).

This study, on the hand, is founded on the Stroop experiment and instead investigates the effect of time on the memorization of color. Therefore, the study examines the impact of color memorization’s duration impact on the ability of the respondents to memorize the colored words accurately. This study’s comprehension of the time aspect reveals the cognitive process in detail and how it is applied in practical situations, such as behavior analysis, education, and decision-making processes. Cognitive interference and its interaction with the stimuli of colors strongly depend on the time of the reader or the color perceiver.

Method 

Participants 

Twenty-three experimental psychology students (20 women and three men, translating to a mean age of 27.2 years) participated in an experiment that measured their ability to read and memorize colored words. Before the experiment, participants were informed about the study’s purpose and provided instructions on how to complete the task.

Materials

Participants were provided with the Stroop Test handout, which explained the instructions on what they (the participants) had to do for each task. The handout also included sets of thirty words in the meaning of colors in black, blue, red, green, and yellow and an answer key for those who were assigned as the checker (refer to Fig 1 and 2). A timer was also used to measure how long it took for each reader to complete each task. For this study, time was measured in tenths of a second.

Design

This study utilized a within-subjects design to examine the effects of time for color memorization on cognitive interference. In this study, students were required to complete seven tasks testing the time effect of cognitive interference; the level of cognitive interference is the dependent variable, while the time taken to perceive and memorize the colors is the independent variable. The level of significance is <0.05

Procedure 

All twenty-three participants were split into groups of three or four individuals and were provided with the Stroop Test paper handout. In each group, everyone was assigned as either the reader, timer, or checker. The reader was tested at the moment, the timer was responsible for keeping track of how long it took to complete each task, and the checker was responsible for keeping track of any errors the reader made for each set. If the reader made more than three errors, they were asked to start all over. For set A1, readers were instructed to read the words shown in black. For set B, readers were instructed to say the colors of the words provided (blue, red, green, and yellow). For set C, readers were instructed to say again the colors of the letters shown, but this time, the words were gibberish (Example: Xbox, big, ozt, xbrz, MPAA). For set D1, readers had to focus on reading the words blue, red, green, and yellow, but to make this a more challenging trial, the words needed to match their colors. For set D2, the reader had to do the opposite of what was done on D1, where they read the color of the words instead of the actual word.

Results

The experiment was performed, and the mean times were as follows: Set A1 (M = 12.877s), followed closely by Set A2 (M = 12.094s) and Set B (M = 13.063s). Set C had a mean time (M = 17.927s), while Set D1 showed a time (M = 14.022s). Set D2 (M = 25.486s) revealed an increase in reading time compared to the other sets. Finally, Set A3 demonstrated a similar time to Set A (M = 10.982s). The mean times for each set are presented in Table 1. A one-way repeated measures ANOVA was performed. Following a post hoc comparisons test, this indicated that Set D2 had a significantly longer reading time than Set A1. (p < .05).

Another one-way repeated measures ANOVA was performed to compare the results on the three levels of practice sets. In comparing means between Set A1 and Set A3, a significant difference was observed, t(22,2) = 1.895, p = 0.009. On the other hand, in the comparison between Set A1 and Set A2, a non-significant difference was found, t(22,2) = 0.783, p = 0.440.

Table 1

The mean and standard deviation for the reading time taken for all levels

Table 2

Multiple Comparisons versus Control Group:

Discussion

In the context of the Stroop Experiment, the study aimed to investigate the impact of color memorization time on cognitive interference. Based on the results, there is essential information indicating the relationship between the color stimuli and cognitive interference in terms of color memorization duration propensity to affect the ability of the participants to memorize colors. According to Table 1, the mean reading of the time differed significantly. For example, even though A1 and A2 means (M) were relatively similar (12.88s and 12.094s respectively) while B, C, and D 1 were more significant with an increased range between them (13.063s, 17.93s, and 14.02 s respectively). The mean for the D2 set was significantly largest (25.86s), indicating increased duration for the memorization. Therefore, set D2 represented the largest cognitive interference.

The results indicated differences between the sets after the one-way repeated ANOVA test and the hoc comparisons. For example, there is a significant difference between A1 and D2, whereby D2 indicated p<0.05. The ANOVA test results support the study’s hypothesis that the longer the time, the increased cognitive interference. If the participants spent more time memorizing the colors, they would be susceptible to cognitive interference. In investigating the impact of practice on cognitive interference, there is a notable difference between A1 and A2 (t (22.2) =1.895 and p= 0.009). The values indicate that the participants in these sets have adopted the ability to overcome cognitive interference. On the other hand, the comparison between Set A1 and Set A2 yielded a non-significant difference (t(22.2) = 0.783, p = 0.440), indicating no significant improvement in reading times between these two sets despite the differences in color memorization time.

The results above are pragmatic proof of cognitive interference theoretical concepts, including automaticity, cognitive control, and attention. The Stroop experiment is a fundamental first-hand and intrinsic study that mainly focused on the concepts, concluding that the automatic process of word-reading interferes with the color identification ability (O’Brien et al., 2021). Since the respondents were engaged in responding to the color memorization at different timespan, the cognitive control system was under different loads and demands of cognitive control systems (Stroop, 1935). Therefore, the longer the time, the increased interference between the meaning of the word or letters and the colors. Such conflicting cognition processing is the foundation of the participants’ inefficiencies in identifying the ink colors (Luna et al., 2020).

The observable difference between A1 and A3 is the pragmatic application of automaticity in reducing cognitive interference. Therefore, when the participants were exposed to more reading tasks, they increased their proficiency in reducing interference through the automatic response developed during practice (Doron et al., 2020). Reducing interference means adopting efficiency in differentiating and processing colored and written information.

Conclusion

The study aimed to investigate the effect of color memorization time on cognitive interference in the context of the Stroop experiment. The study finding gave insights into the relationship between color stimuli and cognitive interference, shedding light on how the duration of color memorization affects the ability of individuals to read and memorize colored words efficiently and accurately. The study’s outcome indicates that the duration increases with increased interference. The results support the concepts of automaticity, attention, and cognitive control in reducing and alleviating cognitive interference. Stroop’s experiment already highlighted the interference and how it can be controlled. Some of the study participants experienced difficulty suppressing the automatic response leading to increased duration of color memorization, causing errors in identifying colors and words. The practice part of the study reveals that consistent practice reduces interference and improves the performance of color and word identification. The study has a limitation of a small sample size, only comprising students studying psychology leading to the generalizability of the outcome. The study also focused on the Stroop experiment disregarding other perspectives that influence cognitive interference. Therefore, due to this limitation, there is a need for further studies with a more extensive and diverse population of participants and the inclusion of other factors of cognitive interference, such as cognitive interference modulation, attentional capacity, and attentional capacity.

References

Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of experimental psychology, 18(6), 643.

Sarason, I. G., Pierce, G. R., & Sarason, B. R. (Eds.). (2014). Cognitive interference: Theories, methods, and findings. Routledge.

O’Brien, E. L., Torres, G. E., & Neupert, S. D. (2021). Cognitive interference in the context of daily stressors, daily awareness of age-related change, and general aging attitudes. The Journals of Gerontology: Series B, 76(5), 920–929.

Luna, F. G., Telga, M., Vadillo, M. A., & Lupiáñez, J. (2020). Depending on the attentional set, the concurrent working memory load may increase or reduce cognitive interference—Journal of Experimental Psychology: Human Perception and Performance, 46(7), 667.

Doron, J., Rouault, Q., Jubeau, M., & Bernier, M. (2020). Integrated mindfulness-based intervention: Effects on mindfulness skills, cognitive interference and performance satisfaction of young elite badminton players. Psychology of Sport and Exercise, 47, 101638.

Appendix

Figure 1: Stroop-Test Instructions

Figure 2: Stroop-Test colors