Stroop Effect

STROOP EFFECT 1 INTRODUCTION Background of the study The color-word naming originated way back almost to the beginning of experimental psychology, in the first psychological laboratory, in Leipzig, Germany. In 1883, Wilhelm Wundt recounted his student, James Mckeen Cattel, to investigate in his doctoral research on the time required to name objects and colors and read corresponding words. The research focused on the duration of naming such objects. Cattell, in 1886, recognized that color naming required more time than word naming and these finding was noted in William James’ book in 1908. In spite of the fact that there were several first experimental studies regarding with colorword naming, the test had not yet achieved its identity until 1929 when an American psychologist, named John Ridley Stroop, devised a test in the laboratory of Erick Rudolf Jaensch (as cited in Killian, 1935). The test shows that people cannot help but process word meanings, and that this processing interferes with the color-naming task. This test was then named as the “Stroop test”. The most intriguing feature of the Stroop test is the conflict or interference situation in which the subject must name the color of the ink of color-words when the color and the word are incongruous. The effect of such test was already noted as the “Stroop Effect”. The “Stroop Effect”, as defined, is the state of color confusion; it is the difficulty in identifying the colors in which names of colors are written (Encarta, 2010). For example, if the word "red" is printed in green ink, people are likely to say "red" when asked the color of the printed word. In March 21, 1929 the identified color-word test, the true “Stroop test”, was first introduced into American psychology. Why has the Stroop effect continued to fascinate psychologists? Part of the answer is that the Stroop effect appears to tap into essential operations of cognition, thereby offering clues to fundamental cognitive processes.

STROOP EFFECT 2 In two classic experiments, Stroop first compared reading a list of words printed in black (verbal condition) with reading the same list of words printed in incongruent colors (Stroopverbal condition). Stroop found that there was little difference in reading time for the two lists. Subsequent to the first, Stroop then compared the naming of colors for a list of solid color squares (intrinsic condition) with the naming of colors for a list of words printed in incongruent colors (Stroop-intrinsic condition). Subjects averaged 74% longer to name ink colors of incongruent words (Mangun, 2012). The results of these two studies led Stroop to conclude that since people are more practiced at word reading than naming colors, there is less interference with word reading than with color naming. The theory of visual selective attention proposes a special status for spatial location in visual processing (Naatanen, 1992). According to Naatanen (1992), selective attention was viewed as selecting between messages arriving on different “channels”. Selecting one “channel” is usually defined on the basis of spatial origin or some other distinctive feature. According to the zoom-lens model, attention is directed to a given region of the visual field. The area of focal attention can be increased or decreased in line with task demands (Eysenck, 2004). Selective attention also has obvious advantages because it allows us to maximize information gained from the object of our focus while reducing sensory interference from other irrelevant sources (Baron & Kashler, 2005). The automaticity model may also explain the concept of the Stroop effect. According to this theory, reading is an automatic process, which cannot be turned off. Automatic processing must occur without intention, without involving conscious awareness and must not interfere with other mental activity (Galotti et al., 2010). In other words, people see the words without much effort or consciousness. On the other hand, naming colors is not automatic. It requires more effort than reading, thus creating interference in the Stroop task. The Stroop effect has often been regarded as involving unavoidable and automatic processing of the color words (Eysenck,

STROOP EFFECT 3 2004). This explanation derives more from Cattell’s theory, with automaticity viewed as a continuum that develops with practice (MacLeod & Dunbar, 1988). In processing stimuli, mainly visual stimuli it was widely recognized that gender is a causable factor. Strickland et. Al. (1997) concluded that there are significant sex differences on time taken to complete the color-naming and word-naming cards. (Baroun & Alansari, 2006) According to Golden and Sarmany there is a widespread agreement among researchers that females tend to have shorter latency on naming color card, while males and females perform almost equally on the word card. Merkarski, et. al (1996) also supports, linked to their findings which indicates that women perform in shorter times on the Stroop test latencies than men. The focus of the experiment; therefore, is on Stroop effect as determined by duration the length of time it will take for the subject to finish the given task. By conducting one experimental setting, the experiment aims to find out if there is a significant difference among the four conditions in terms of duration, this is to prove whether Stroop findings was applicable. Second, the experiment aims to find out whether gender is a causable factor on Stroop effect and to prove whether the findings stated by Baroun and Alansari (2006) is likewise applicable. STATEMENT OF THE PROBLEM AND HYPOTHESES 1. What is the significant difference between males and females in the four conditions namely: a.) Verbal b.) Intrinsic c.) Stroop Verbal and d.) Stroop Intrinsic in terms of duration of response? There is a significant difference between males and females in the four conditions namely; a. Verbal, b.) Intrinsic, c.) Stroop Verbal and d.) Stroop Intrinsic, in terms of duration of response. Females have shorter duration than males, in completing the four conditions. 2. What is the significant difference among the four conditions namely; a.) Verbal, b.) Intrinsic, c.) Stroop Verbal and d.) Stroop Intrinsic, in terms of duration of response? There is a significant difference among the four conditions namely; a.) Verbal, b.) Intrinsic, c.) Stroop Verbal and d.) Stroop Intrinsic, in terms of duration of response.

STROOP EFFECT 4 Verbal condition has the shortest duration among the four conditions and Stroop-intrinsic condition has the longest duration among the four conditions. METHOD Subjects Twenty-four undergraduate students of Saint Louis University, Navy Base Campus acted as subjects as a part of the experiment. Of the 24 subjects, 12 were males and 12 were females. The subjects were selected randomly based on their availability during the time of the experiment. Apparatus Two sets of stimulus boards were used in the experiment. The first set of stimulus boards were the “trial boards”. The experimenter used three trial boards with white background. Each trial board consisted of three conditions, namely: verbal (with written words red, blue, yellow, green and black that are printed in black ink) with a size of 5.5x20 inches, intrinsic (each rectangle is colored with red, blue, yellow, green and black) with a size of 9x20 inches and Stroop, which can be verbal or intrinsic as well (written name of colors with different font colors) with a size of 7.6x17.5 inches. For each trial board, five words (verbal) and five rectangles (intrinsic) are printed on it to be read or recognized. The second set of stimulus boards were the “actual boards”. The experimenter used three actual boards with white background and with a size of 30x20 inches each. Each actual board has the same conditions applied to it as the trial boards. The only difference between the two boards is that the actual boards consisted of 20 words, arranged in a 4x5 matrix of evenly spaced rows and columns and the intrinsic board consists of rectangles with a size of 5x2 inches. For this experiment, a stopwatch (cellular phone) was also used to record the time duration the subjects are able to read or recognize all the words or colors in the actual board. As for the applicable standard unit of measurement, seconds and milliseconds were used.

STROOP EFFECT 5 Procedure First, the experimenter prepared the boards to be used in the experiment. Subsequently, the recorders prepared the record sheets and the timers to be used. The recruiters dispersed themselves around the GD building to look for subjects. They politely asked each person they meet if they were willing to participate in the experiment. An available and willing subject was brought to the cubicle in the 7th floor where the experiment is performed. Each subject who entered the cubicle was greeted by the experimenter and the recorders. The subject was asked to sit and relax on the chair provided, facing the south wall of the cubicle. When the subject was ready, the experimenter gave instructions and further explained how the experiment will take place. They began the experiment with a trial. The experimenter showed the subject 3 trial boards — each with different a different condition or stimuli (verbal, intrinsic, Stroop verbal, Stroop intrinsic). For the first board, the experimenter asked the subject to read the words placed on the board. For the second board, the experimenter asked the subject to name the color of the rectangles on the board. And lastly, for the third board, two instructions were given: first, to read the words on the board and second, to tell the font color of the words. When the subject finally finished the trial boards and understood the instructions, they moved on to the actual experiment. In the middle of the experiment, the subject was entertained in order for him/her not to be bored. This was done before proceeding to the actual experiment. In the actual experiment, the experimenter used the actual boards. For each board, 4 columns with 5 words were present. The subject was asked to read the words column to column, from top to bottom. The instructions given for the actual boards were the same with the instructions given for the trial boards. In the first actual board, the experimenter instructed the subject to just read the word he would see. For the second actual board, the subject was asked to tell the experimenter the color he/she saw on each rectangle on the board. Lastly, the third board was used twice for

STROOP EFFECT 6 two different conditions. For the first instruction of the last board, the subject was asked to read the word he sees, but now with a twist — the words were written in colors different to its name. For the second instruction given, the subject was asked to tell the color of the word in which it has been written or the font color. The subject only started reading when the experimenter gave the go signal. The go signal was also the cue for the recorders to start recording. After the subject was finish with the first board, the recorder stopped the timer. The recorder then wrote on the record sheet how long the subject took for him/her to read all the words on the board. Once done, everyone in the cubicle thanked the subject and escorted him/her outside the cubicle. The same procedures were followed for all 30 subjects. Treatment of Data The data in problem no. 1 were analyzed using t-Test for uncorrelated sample means (tTest: Two-Sample Assuming Equal Variances) with gender (male and female) as the parameter factor and the mean time duration for each of the four conditions as the real factor. The data in problem no. 2 were analyzed using analysis of variance (ANOVA): single factor design for correlated sample means (ANOVA: two-factor without replication) with the time duration as the within subject factor and the four conditions as the between subject factor. The statistical analyses for both problems were carried out by means of manual computation and were verified using statistical package for social science (SPSS) for Windows Version XP, both computations standardized at significance level   0.05.

STROOP EFFECT 7 RESULTS AND INTERPRETATION The following results obtained through application of the appropriate statistical treatment for each problem: Problem no. 1: t-Test: Two-Sample Assuming Equal Variances T-TEST SUMMARY TABLES: VERBAL CONDITION

Females Males Mean 9.519 9.694 Variance 3.823 9.364 Observations 15 15 Pooled Variance 6.594 Hypothesized Mean Difference 0 Df 28 t Stat - 0.186NS t Critical two-tail 2.048 The table above shows the full summary of the t-test done for verbal condition. The results clearly presented that the t-value of - 0.186 falls within the critical region of 2.048 at   0.05 and is therefore, not significant. Hence, we can conclude that there is no significant difference between males and females in their time duration for the verbal condition. INTRINSIC CONDITION Mean

Females 10.290

Males 11.201

2.035 5.194 Variance Observations 15 15 Pooled Variance 3.614 Hypothesized Mean Difference 0 Df 28 t Stat - 1.312NS t Critical two-tail 2.048 The table above shows the full summary of the t-test done for intrinsic condition. The results clearly presented that the t-value of -1.312 falls within the critical region of 2.048 at   0.05 and is therefore, not significant. Hence, we can conclude that there is no significant difference between males and females in their time duration for the intrinsic condition.

STROOP EFFECT 8 STROOP-VERBAL CONDITION Mean

Females 9.759

Males 10.743

4.659 13.848 Variance Observations 15 15 Pooled Variance 9.254 Hypothesized Mean Difference 0 Df 28 t Stat - 0.886NS t Critical two-tail 2.048 The table above shows the full summary of the t-test done for Stroop-verbal condition. The results clearly presented that the t-value of 0.886 falls within the critical region of 2.048 at   0.05 and is therefore, not significant. Hence, we can conclude that there is no significant difference between males and females in their time duration for the stroop-verbal condition. STROOP-INTRINSIC CONDITION Mean

Females 14.874

Males 16.304

13.710 15.336 Variance Observations 15 15 Pooled Variance 14.522 Hypothesized Mean Difference 0 Df 28 t Stat - 1.028NS t Critical two-tail 2.048 The table above shows the full summary of the t-test done for Stroop-intrinsic condition. The results clearly presented that the t-value of -1.028 falls within the critical region of 2.048 at   0.05 and is therefore, not significant. Hence, we can conclude that there is no significant difference between males and females in their time duration for the Stroop-intrinsic condition. The general results of the statistical analyses in problem no. 1 evidently presents that all of the t-value for each of the condition (verbal, intrinsic, Stroop-verbal, Stroop-intrinsic) are insignificant at   0.05. Therefore; the alternative hypothesis which states that there is a significant difference between males and females in the four conditions, in terms of time duration is REJECTED. Thus; this evidently shows that males and females have significantly

STROOP EFFECT 9 performed the same in terms of the length time it took them to complete (duration) the tasks (four conditions). Gender is not a causable factor in to prove “Stroop-effect” as determined by time duration. Problem no. 2: ANOVA: Two-Factor Without Replication DATA SUMMARY TABLE: Groups Verbal Intrinsic Stroop-verbal Stroop-intrinsic ANOVA TABLE:

Count 30 30 30 30

Sum 288.20 322.36 307.53 467.67

Average 9.61 10.75 10.25 15.59

S2 6.37 3.70 9.19 14.55

Source of Variation SS df MS F P-value F crit Columns 522.00 2 261.00 36.20* 0.00 3.16 Error 418.20 58 7.21 Total 1317.77 89 Shown above is the summary table of the statistical treatment ANOVA. The data clearly shows that the F-value of 0.535 falls beyond the critical value  3.16 at  = 0.05. Therefore; the alternative hypothesis which states there is a significant difference among the four conditions, namely: a) verbal b) intrinsic c) Stroop-verbal d) Stroop-intrinsic in time duration is ACCEPTED. Hence, we proceed to the Tukey Method. CLUSTERING: VERBAL = 9.61 STROOP-VERBAL = 10.25 INTRINSIC = 10.75

STROOP-INTRINSIC = 15.59 There is a significant difference among the four conditions in terms of time duration. Verbal, Stroop-verbal, and intrinsic conditions do not significantly differ from one another in

STROOP EFFECT 10 terms of time duration. The three having the shortest time duration, means that they were equally performed faster. On the other hand, the Stroop-intrinsic condition having the longest duration means that it was the task performed the slowest. This implies that verbal, Stroopverbal and intrinsic conditions have the least “Stroop effect” or none at all, compared to Stroopintrinsic who has the highest manifested “Stroop-effect”. DISCUSSION The purpose of this experiment is to explore more about the Stroop effect. More specifically to find out if there is a significant difference between males and females in terms of duration for each of the conditions and to find out if there is a significant difference among the four conditions (verbal, intrinsic, Stroop-verbal and Stroop-intrinsic) in terms of time duration. For the first problem, the researchers found out that gender is not a causable factor to prove the Stroop effect as determined by time duration (Baroun & Alansari, 2006). According to Golden and Sarmany, there is a widespread agreement among researchers that females tend to have shorter latency on naming color card, while males and females perform almost equally on the word card. Merkarski, et. al (1996) also supports, linked to their findings which indicates that women perform in shorter times on the Stroop test latencies than men. According to Ligon (1932), women tend to perform better on color naming while men and women tend to perform equally on word naming. In addition, Peretti (1971) reported the difference favoring females on color-word naming. A study was conducted by Barbara Dozier which confirmed the findings that states there is gender difference between males and females. On the same research, Alansari & Baroun (2003) investigated performance differences related to gender and culture using Stroop color and word test. However, it was found out that there is no difference. Though there were a lot of studies that reported there is a significant difference between males and females in terms of “Stroop effect”, there were also valid studies and evidences that reported there is no difference in gender when it comes to word or color naming. A study that

STROOP EFFECT 11 was done by Insua (2002), conducted on 2000 English and Spanish subjects in the United States, showed no gender difference in performance across all Stroop test. Proving such studies, Galer et. al, (2014) stated gender has significantly lower effect in processing visual stimuli, compared to age gaps, educational attainment and prior training and experiences. He said that, time related differences between individuals have greater effect on the speed in processing stimuli. Other than organic variables (biological factors), environmental variables have a more or less higher influence on results of experimental-based researches. This was proven to be true by (Flaudias & Llorca, 2014). Huguet, et al., who conducted an experiment, found that another person’s presence during the test significantly reduced the Stroop effect. They showed that in the presence of a coactor or simply a presence, the Stroop effect decreased in comparison with a situation where the participant was alone in the room. Conty, et al., (2014) further elaborated this, claiming that in an experimental setting, results were influenced more by the feeling of being watched than by the presence of others. In this case, emotional states caused by individual differences might be triggered (Baron & Kalsher, 2008). For example, if a male subject who has inferiority complex and who has a high anxiety tendencies, is introduced to a time pressured task with the presence of strangers, his performance will be poorer compared to a female who don’t have confidence and trust issues (Baron & Klasher, 2008). Another reason as to why gender is a weak basis is the fact that the reduction of Stroop interference may be the result of the task-specific nature of the effort procedure used (MacKinnon, et al. 1985). This means that the prior training might affect the speed of performance of a certain person if the actual task is already introduced. Thus, effort is an important mediating variable to be considered in all strop studies. Since the subjects were exposed to trials, they were already given clues as to how the actual task would take place, and according to Galer, et.al (2014), if a set of people is equally

STROOP EFFECT 12 introduced to a certain task, this may reduce their ability to exhibit differences among them. Prior training may directly lessen the typical performance of a person. For the second problem the researchers have found out that there is a significant difference among the four conditions. It was proved that verbal, intrinsic, and Stroop-verbal conditions have the least “Stroop effect” or none at all. According to the findings of Hubel and Wiesel, many brain cells respond only to lines of a certain width or orientation (Coon, 1995). These same cells didn’t get the least bit ‘excited’ over a dot of light or overall illumination. Other cells responded only to lines at certain angles, or lines at certain lengths, or lines moving in a particular direction. The upshot of these findings is that cells in the brain seem to first analyze incoming information into such sequence: lines-angles-shading-movement-and other basic features. These findings explain why we process written words and shapes faster than colors, since words and shapes have more definite lines and angles we tend to recognize them more quickly than colors. On the other hand, it was also proved that the Stroop-intrinsic condition having the longest time duration has the highest established “Stroop effect”. What could be an explanation to this? According to Banich & Compton (2011), in processing of stimuli, if the stimuli are of the same sensory modality, you must try to divide your attention between the two sources of information. Although we control the focus of our attention, at least to some extent, certain characteristics of stimuli can cause our attention to shift suddenly. Features such as contrast, novelty, stimulus intensity, color and sudden change tend to attract our attention (Baron & Kalsher, 2005). Hence, most of the time, the Selective Attention Theory is applied. In this theory, it states that if there are competing stimuli, the attention mechanism focuses on one stimulus (the attended message) and blocks out the other stimulus (unattended message). But on the other hand, the unattended message is not fully blocked out. There is a certain degree of registration because when the special information is included, it cannot be overlooked.

STROOP EFFECT 13 This explains why the Stroop-intrinsic condition elicits a longer duration. Since there are two competing stimuli: the word (unattended message) and the color (attended message), the subject had some trouble in recognizing the right stimulus to process and the right response. Furthermore, the findings of Hubel and Wiesel stated above added as to why Stroop-intrinsic condition elicits the longest duration. Since the words become the unattended message, it was harder to block out because as said earlier our brain tends to recognize words quickly than colors. That is why subjects had a longer time in processing the Stroop-intrinsic condition because the unattended message is a very strong distractor. CONCLUSION The researchers conclude that there is no significant difference between males and females, in terms of time duration among the four conditions, namely: a) verbal b) intrinsic c) Stroop-verbal d) Stroop-intrinsic, where females is said to have a shorter time duration compared to males. Therefore the alternative hypothesis is REJECTED. These results claim that gender is not a causable factor in to prove “Stroop-effect” as determined by time duration. The researchers also concluded that there is a significant difference in terms of time duration, among the four conditions, namely: a) verbal b) intrinsic c) Stroop-verbal d) Stroopintrinsic; therefore the alternative hypothesis is ACCEPTED. Verbal-condition having the shortest time duration and Stroop-intrinsic having the longest time duration is proven to be true. These results claims that, verbal conditions have the least “Stroop effect” or none at all, compared to Stroop-intrinsic condition which has the highest manifested “Stroop-effect”. RECOMMENDATIONS When driving, it is advisable most especially for the males, given that they are more inclined to such activity, to be more careful and attentive in observing traffic signs, to avoid accidents and penalties. People should also avoid the male driver stereotype. The findings in this research proved that females may also be as capable as male in the driving department.

STROOP EFFECT 14 When visiting the grocery stores or markets, most especially for the females since they are much inclined to such task, colors can help them better to distinguish the condition of the goods they are buying. For example when buying fruits and vegetables, color is good determinant whether the fruit or the vegetable is fresh and ripe or rotten. This way they can avoid to be fooled by foolish vendors. For those storeowners or businessmen who are planning to build commercial buildings along the road, it is advisable for them to create signage/posters/billboards that are easily readable - with readable font, font size, and font color. Also avoid using font colors that will make the letters troublesome to read for easy location of the place, and avoid using colors that are too distracting for the motorists to avoid causing unwanted accidents. It is advisable for writers, teachers, students and others who are planning or obliged to make illustrative reading devices, visual aids and flashcards, to see to it that the colors they are going to use in making their visual devices must blend appropriately with the words written, for easy and quick comprehension of words or the concept of the written material. REFERENCES Baron, R.A. & Kalsher, M.J. (2005). Introductory Psychology (taken from Psychology: From Science to Practice). (custom ed.). (pp. 54 - 55). Boston, MA: Allyn and Bacon. Baroun, K. & Alansari, B. (2006). Gender Differences in Performance on the stroop test. Social Behavior and Personality, 34(3). 309-318. Kuwait University, Kuwait. Banich, M.T. & Compton, R. (2011). Cognitive Neuroscience (3rd ed.). (p. 317). Belmont, CA: Wadsworth. Coon, D. (1995). Introduction to Psychology: Exploration and Application (7th ed.). NY: West Publishing Company. Eysenck, M.W. (2004). Psychology: An International Perspective. (pp. 193 – 217). NY: Psychology Press.

STROOP EFFECT 15 Flaudias, V & Llorca, P.M. (2014). A brief review of the three manipulations of the stroop taskfocusing on the automaticity of semantic access. Psychologica Belgica, 54(2), 1991221. DOI: http://dx.org/10.5334/pb.am Galotti, K.M. et. Al. (2010). Cognitive Psychology: In and Out of the Laboratory. (pp. 110 – 113). Toronto: Nelson Education. Insua, M. C. (2002). Performance on the Stroop colour and word test as a function of language in bilinguals. Dissertation Abstracts International: Section B: The Sciences & Engineering, 63(1-B), 559. James, W. (1908). The Principles of Psychology (Vol 1). (p. 559). London: Macmillan. Killian, G. (1985). The Stroop Color-Word Interference Test. In Keyser, D., & Sweetland, R. (Eds.), Test Critiques (Vol 2). (pp. 751 – 758). Kansas City, MO: Test Corporation of America. Ligon, E.M. (1932). A genetic study of color naming and word reading. American Journal of Psychology, 44, 103 – 121. MacKinnon, D. & Geiselman, E. et. al. (1985). The Effects of Effort on stroop Interference. Acta Psychologica, 58. 225-235. University of California, Los Angeles, USA. Macleod, C.M. (1991). Haifa Century of Research on the Stroop Effect: An Integrative Review. American Psychological Association, 109(2), 163 – 203. Mangun, G.R. (ed.). (2012). The Neuroscience of Attention: Attentional Control and Selection. (p. 230). New York, NY: Oxford University Press. Naatanen, R. (1992). Attention and Brain Function. (pp. 27 – 40). NJ: Lawrence Earlbaum Associates. Peretti, P. O. (1971). Effects of noncompetitive, competitive instructions, and sex on performance in a color-word interference task. Journal of Psychology, 79, 67-70.