Effect of Color and Word on Response Time
Lidia Emelina
Brooklyn College of CUNY

Abstract Selective attention is the act of focusing on a particular object for a period of time, while simultaneously ignoring irrelevant information. It happens on a daily basis and seen in basically any interactions (at school, at work, at store and etc). Many different researches were done with relevance of Stroop Effect, which allowed scientist to examine differences in gender, age, as well as education on the intervention effect. The METACARD software was used to explore the effect of congruent and incongruent stimuli on the reaction time of participant’s performance. The data is from 46 participants are presented here. Results revealed that when word and color match, participants have faster responses and less errors. When word and color do not match, participants have slower responses and make more errors. The Stroop effect demonstrates the dynamic of selective attention, illustrates the nature of automatic processing, and shows that people can improve their selective attention.
Keywords: selective attention, interaction, stroop effect, automatic processing.
Introduction
The phenomenon of interference takes a large place in experimental psychology and demands our attention. Many psychologist investigate inhibiting effects nowadays. However, the psychologists began to study interference prior to 1890. Many experiments were conducted to investigate color naming and word reading. The Stroop Effect was discovered by John Ridley Stroop. The Stroop task experiment was done and first reported in scientist’s Ph.D. dissertation that was published in 1925. In the color ­word, Stroop presented (Stroop, 1935) the participants with words printed in color and were asked to identify the color of the ink while ignoring the meaning of the word. Stroop compared the reaction time when reading names of the colors, with the reaction time when naming the colors. It took more time for participants to identify the color of incongruent words (e.g. red letters spelling the word “yellow”) than congruent words (e.g. blue letters spelling the word “blue”). This difference in reaction time is called “Stroop interference effect”. Stroop effect has been replicated many times and current theories continue to struggle to explain it (for a review, see MacLeod, 1991). In previous experiment, Pritchatt (1968) showed a reduction in interference by matching task using color markers over the buttons, but little reversal. It was showed that, by allowing subjects to match the color of the print with color patches instead of words, the interference due to the written word can be considerably reduced. Many tasks were conducted to examine the nature of attention and automacity. Perhaps the most extensively studied task have been the search task of Shiffrin and Schnieder (Schneider & Shiffrin, 1977) and the Stroop task (Stroop, 1935). However, skilled readers cannot control nor prevent reading single words even if it is instructed to do so. This allow for interference effect in color word Stroop task. A skilled reader may pay attention to the meaning of the words and pay less attention to the color of the ink, which the word is printed. The Stroop effect is important as it allow studying interference between different information that our brain receives on the daily basis. The present study examines Stroop’s phenomena of interference. In the first (color) condition of the experiment, participants were required to respond to the color that the target word was shown, ignoring the word itself (word was named in different color). In the second (word) condition, participants were required to respond to the color named by the word, ignoring its incongruent color. In both conditions, the response was to press the “SPACE” bar on the keyboard. We predict that reaction time for color naming will be higher than for word naming.
We also predict that reaction time will be higher for incongruent stimuli than for congruent stimuli. We suggest that it might be an interaction between congruency and identification task.
Method
Participants Forty­ six Brooklyn College Undergraduates (mostly females than males) of different races, religions, and socioeconomic backgrounds participated in a “Stroop Effect” experiment. The students participated for partial fulfillment of course requirements and were not financially compensated.
Research design Current experiment has 2×2 (“two by two”) within subject factorial design with two independent variables: congruency and identification task. Each independent variable has two levels: 1) congruent stimuli (e.g. the word “RED” written in red ink); 2) incongruent stimuli (e.g. the word “RED” written in green ink). Two levels for identification task are: 1) color identification; 2) word identification (Figure 1). Dependent variable is a measure construct that is the interest of the experiment. There are two dependent variables in this experiment: 1) reaction time:.
Materials
The current study, conducted on PCs running in house METACARD software. The screens were 15” LCD. Four numbers of words were used (red, green, blue, yellow) and four colors were used (red, green, blue, yellow). The results were recorded on the pieces of paper by hand. Two ­way ANOVA test was performed to calculate statistics in SPSS.
Procedure
Participants were placed in separate rooms and sat at the computers. Task instructions were presented visually (on the computer screen) at the beginning of the experiment. The participants were informed that on each trial they would be presented with a word written in one out of four different colors. As each student was proceeded to the trial, the instructions appeared in the center of the screen and instructed participants to type whether the name of the word, or the name of the color. The trials were done in blocks: in the first block of 48 trials, participants were asked to name the word, yet ignoring the color; in the second block of 48 trials, participants were asked to name the color, this time ignoring the word. Total of 96 trials were done. Each trial began with the presentation of a fixation cross in the center of the screen. The fixation cross was visible for 500 milliseconds. When the fixation cross was removed, it immediately followed be the word and color stimulus. The Stroop stimulus remained on the screen until a response was typed and the participant press the spacebar. Immediately after the response, the stimuli were removed from the screen, the next trial was triggered 500 milliseconds after the last keypress. At the end of the experiment, each student was asked to compute the results by pressing the button “Calculate” and to record his/her results for each condition (color identification task, word identification task) on the piece of paper.
Results
To test our hypothesis we stated alpha level 0.05. “ Two way” ANOVA test showed that the main effect of identification task on the reaction time was significant F(1,45)=84.688, p<0.05 and the main effect for condition (congruent/incongruent) was also significant F(1,45)=42.264, p<0.05. There was a significant interaction between task and congruency F(1,45)=29.924, p<0.05. As shown in Figure 2, for pair 2 took less time to name a color in congruent condition (1056.76 msec) than in incongruent condition (1215.65 msec). For pair 1 took almost the same time to name the word in congruent (875.09 msec) and in incongruent conditions (876.85). We computed means for each pair: pair 1 M= 1.76087 and pair 2 M= 158.89130. T­test was done further to explain the interaction between pair 1 and pair 2. The interaction indicated greater interference for the pair 1 t(45)= ­.115, p>0.05 than for the pair 2 t(45)=­.7.238, p<0.05, Table 1.
Discussion
In our study, we examined the relation between incongruent/congruent stimulus and
Stroop’s interference. The experiment was design to study the control attention process that are responsible for selecting task­ relevant information and ignoring irrelevant information. Each participant took a part in every condition. The present experiment supports Stroop’s findings that the reaction time increases for both word and color naming when the person is presented with incongruent words than with congruent. Seymor (1977) suggests that Stroop interference occurs during conceptual encoding, a stage between perceptual encoding and response activation when color information contacts semantic memory. Simon and Berbaum (1988) conclude based on the finding how significant Stroop effect is in a retrieval task. Therefore, the most likely locus of interference is the stage between perceptual encoding and response selection: i.e. the stage perceptual encoding or retrieving information from short­ term memory. The results of our experiment also support recent research, which indicates that incongruent ink colors can also interfere with responses to word naming (Flowers 1975; Simon & Sudalaimuthu 1979; Uleman & Reeves 1971).
Another interesting aspect of our results was finding that reactions were significantly faster to the congruent stimulus than to the incongruent stimulus. Welford (1961) suggested that subjects inspect a stimulus until 'sufficient' data are gathered to make a response. Reactions are faster to a short duration stimulus because the intake of data is stopped by the cessation of the stimulus, therefore, subjects gain little or nothing by delaying their reaction. The results largely confirm the experimental hypothesis, which stated that reaction time increases when participants are presented with incongruent stimuli. It was proved that reaction time is higher for both word and color­ naming when the meaning of the word and the color of ink are not being same (word “GREEN” printed in green red). We also predicted that reaction time increases when identifying color of the word for both congruent and incongruent tasks. The results of our study supported this prediction. The reaction time is found to be higher for identifying the color of the ink than color/meaning of the word for both stimuli (congruent and incongruent). The interaction in the main error analysis indicated that interference was greater in the word task than in the color task. As we predicted, the reaction time was higher for incongruent stimuli than for congruent. The current experiment was restricted by the number of its participants. It also may be the result that we retained the null hypothesis for the word naming (pair1) and rejected the null hypothesis for color­naming (pair 2). We made a correct decision about our hypothesis. We believe that replication of this experiment with the greater number of participants could lead to significant findings of the effect. We suggest that slightly changing the task of the experiment may show different results. We believe that coloring a single letter instead of the entire word can control some of semantic processes in reading. As a result, it might prevent interference effect. We also suggest that change of the stimuli from word to nonsense words (such as “kiw”, “thoz’, etc.) would produce a different pattern of results, which could be a good idea for future studies in this area. Good paper.
Intro left something to be desired. You didn’t explore the models that account for stroop-like results enough. Didn’t explan them fully anywhere in the text (didn’t connect them to the results you found).
Some more clarity would be needed in the results sections, with regards to the t-tests.
Grade: 92

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Figure 1. The design of the experiment .

Table 1. Results of the Stroop Effect experiment .

Figure 2. Reaction time for pair 1, word­naming (congruency) condition and pair 2 color­naming (congruency) condition.