Stroop Effect in a Persons Reaction - Essay Example

Stroop Effect and Dilution as Affected by Word or Nonword Flankers Tracy Berne Word Count: 2,042 The Stroop effect has been considered by cognitive psychologists as a useful tool in word recognition processes. However, some questions are raised whether Stroop effect and its reduction is lexical or not. To verify the facts a 2 x 3 repeated measures design experiment with type of word stimulus (congruent colour name, incongruent colour name, and non-word ) and type of flanker manipulation (no flanking word versus flanking word) as independent variables was conducted. A total of 194 randomly selected participants 56% male and 64% female ages 16-60 were subjected to Stroop Test. SPSS Repeated Response ANOVA and T-test were used to determine the significant effects of the factors and compare the means of the treatments, respectively. The study found that Stroop effect and dilution are lexical in nature. The results showed that greater Stroop effect is manifested when colour word is used compared to the use of nonwords in the test. Meanwhile, Stroop dilution is higher when colour patch is flanked by a nonword stimulus than with the use of colour words. Introduction Stroop effect manifests in a person's reaction to recognize first the written stimulus by reading it before analyzing the colour it is written. It was first reported by Stroop in 1935 (as cited in MacLeod, 1991).This is an important process in psychology since the ability to manipulate or control Stroop effect has something to do with improving the cognitive abilities of individual and increases the chances of good judgment and decisions in actual world scenarios. Several studies prove that Stroop effect is observed in different conditions and that dilution can be performed by different parameters included in the stimulus and the stimulus itself. Different authors argue on the context of Stroop effect and the process to minimize it which is commonly referred as "Stroop dilution". Kahneman and Henik (1981) challenged the generalized notion that reading is automatic response and indispensable. They noted that if reading is automatic, it should not be affected by the placement of the word. To prove their point they found out that spatial separation between the ink colour and the incongruent colour name could reduce the strength of the Stroop effect. The study of Kahneman and Chajczyk (1983) showed that Stroop effect is reduced when the incongruent colour word and neutral words are placed to the side (flanks) of the colour patch. Their findings challenged the notion that processing the meaning of a word is automatic. They noted that interference attributed to the Stroop effect required attention and that spreading the attention in more locations causes reduction of the Stroop effect. Cho, Lien, and Proctor (2006) found out that neutral words can reduce the Strop effect when they serve as colour carrier, but not when the colour word was the colour carrier. They argue that Stroop dilution is due to attentional competition between the colour word and the neutral word, with priority given to the colour carrier. The finding is based on the fact that both colour carrier and neutral words are colour words. Studies suggested that Stroop dilution is nothing to do with reading, but it is merely due to diversion and visual interference. Brown, Roos-Gilbert, & Carr (1995) reported that the reduction of the Stroop effect does not differ when words or symbols are used. The idea could be true since Stroop dilution studies use tachistoscopic presentation that limits the role of eye movements. If this is true the result of Cho, Lien, and Proctor's (2006) study may not be affected if the stimuli used are nonword. If in the aforementioned cases the Stroop dilution was a result of a limited visual search as brought by tachistoscopic process, then the effect should disappear when a person scans thru a list. If otherwise, then Stroop dilution would be shown when a person looked at lists of words. In the other hand, Roberts and Besner (2005) revealed that a Stroop effect is observed when the colour carrier is from a different type of characters than the colour word distractor. They noted that in the context of Stroop dilution the extent to which flanking distractors are processed depends on the material or Stroop dilution is material specific. This idea is in contrast with that of Brown, Roos-Gilbert, & Carr (1995) mentioned earlier. Whichever is true, these findings pose a challenge with respect to the real sense of Stroop dilution. Are reductions in the size of the Stroop effect a consequence of imposed limitations upon visual search or do they reflect competition for lexical processing If the reading process was important, and the phenomenon involved competition for lexical activation, then we would expect differences in the size of the Stroop effect as a function of whether words or nonwords were presented, but if visual interference was the issue, then there should be little difference between flanking incongruent colour names and non-words. This experiment would therefore validate if a Stroop effect exist in presenting a list of nonword stimuli as against congruent and incongruent colour names. It also aims to replicate the findings of Kahneman and Chajczyk (1983) on the effect of flankers on Stroop dilution and to verify if the meaning of the flanking word would affect the dilution effect. Based on the ideas mentioned it is therefore hypothesized that Stroop effect is greater when incongruent colour word is used as against nonword samples. Furthermore Stroop effect is reduced by flankers and that the meaningfulness of the flanking words would not affect the Stroop dilution effect Method Participants A total of 194 respondents were randomly selected and were subjected to the Stroop tests. The profile of the respondent is an important factor in cognitive test since responses varies with age and sex (Trafton, Richard S., Garrison, William T., 1982). However, this study did not consider sex and age as a factor in identifying the respondents. The participants tested include 54% female respondents and 46% male and age ranges from 16-60 with a mean of 30.9 (SD=14.2). Design The experiment was conducted using a 2 x 3 repeated measures design with type of word stimulus (congruent colour name, incongruent colour name, non-word control) and type of flanker manipulation (no flanking word versus flanking word) as independent variables. The dependent variable is time required by the respondent to name the colour of the stimuli. Materials The stimuli are a list of colour names printed in congruent colour, incongruent colour, and nonword. All stimuli are printed in CAPITALS in centre of column. The colours used in the test are similar to the ones used by Kahneman and Henik's (1981) which are red, blue, and green. The nonwords used as control correspond to the length of the experimental colour names but are of different character. These are: PON for RED, DIMP for BLUE and STOAP for GREEN. Each respondent were presented with a set of stimuli containing 6 samples from each of the 6 treatments under study. The list of test materials used in the test instrument is presented in Appendix A. Procedure The test instruments were presented to respondents who use English as their first language with no problem in naming the colours. A form was filled up by the participants to show their consent in participating in the study. After a thorough explanation of the process the respondent was ask individually to identify the colour of the stimuli and the time it took them to name the colour were recorded and analyzed. Statistical Analyses The profile of the respondents for the experiment was analyzed using SPSS descriptive tests. Data obtained from the study were subjected to SPSS Repeated Measures ANOVA. The test also determined the inter-action between the two factors and its effects on the responses. The t-test was used to determine which treatment means differ from the other. Results The data obtained were analyzed using SPSS Version 14.0. The means and standard deviations of the naming times were obtained using SPSS descriptive analysis and results are presented in Table 1. Table 1 Mean Colour Naming Times in a Stroop test Coloured Word Flanking Word ______________________________________________________________________________ Congruent colour 18.4(6.8) 21.4(9.3) N= 194 _____________________________________________________________________________ Incongruent colour 30.0(11.7) 22.7(13.2) N = 194 _____________________________________________________________________________ Non-word 21.3(6.1) 20.3(5.9) N=194 The results show that samples with flanking words are named faster by the respondents except for treatments where congruent colour is used. The longest time is recorded with samples having coloured word with incongruent colours. The lowest value is recorded with samples having coloured word with congruent colours. The two-way repeated measures analysis of variance (ANOVA) (Appendix C) show there was a significant differences between the naming times of the coloured word treatments (F=127.06), the flanking word treatments (17.03), and the interaction between the two factors (F=91.1) at p Read More