Running head: Colors, Words and Interference
Stroop Effect: How Word Interference Effects Reaction Time When Asked to Say the Color of Ink, Rather Than the Printed Word
Adelphi University
Abstract
The Stroop test is a widely investigated phenomena dealing with cognition and reaction time. The finding that the reaction time increases when asked to name the color of ink a word is printed in rather than the name of the competing printed color. For example, the word blue is printed in red ink. Studies show that skilled readers can not refrain from computing the lexical and semantic representation of a word (Besner & Roberts, M.A., 2005). The overloading of an individual’s limited processing capacity by words and incongruent color can cause a delay in total processing time.
“The Stroop phenomenon has been explained by two contrasting approaches, perceptual conflict and response competition. The former refers to a proposed overloading of an individual’s limited processing capacity by word and incongruent color, involving both relevant (color) and irrelevant (word) information, thus causing delay in total processing time. The latter concerns the response initial stage, where two competing responses use a single response channel. While color stimulus requires transformation from a perceptual to a verbal code, such transformation is not required for word stimulus. Hence, irrelevant word information reaches the response initiation stage before the relevant color information, causing interference apparent in the Stroop task (Alansari, 2004).”
Stroop Effect: How Word Interference Effects Reaction Time When Asked to Say the Color of Ink, Rather Than the Printed Word
What is the Stroop effect or phenomenon? Does one’s visual and cognitive process work simultaneously together? Does one process have a greater effect on the other? According to the findings in the original Stroop test, when color words are presented in colored ink that does not match the printed word; people are slower to respond when naming the color of the ink and not the printed word.
The purpose of this experiment is similar to the original Stroop design, but with extension. Originally, the Stroop test was performed on adults. In the first part of the experiment, the adult participants were to read the word red, printed in the color red, the word blue, printed in the color blue, and so on. During the second phase of the experiment, the same participants, through repeated measures, were to say blue, the color of ink that the word red was printed in, and the color green that the word red was printed in, and so on. As predicted, the results of this test concluded that there was a significant delay in response time on the second part of the test.
However it may be similar, the present experiment is a variation of the original Stroop design. Participants are adolescents, not adults, and instead of reading the word red in the red ink, they stated the color of the rectangles printed on the first sheet of paper; there are no words involved in this part of the test. Then, on the second part of the test, they will state the color of the words. Rather than the word being various color names, the words are names of various animals.
Since the average American child is trained at an early age to be a natural reader, by adolescence, a child will naturally read the words presented to him or her without being asked, and also while trying to avoid the reading process. So if a child is given competing stimuli, information will naturally be processed by reading the words given, even though the child is trying to focus on the other stimulus given. This will cause a delayed reaction time because the child cannot process the information as quickly as he or she would have with no competing stimuli. Consistent with the authors’ predictions, there was a difference in response times between the two parts of the tests, as in the original Stroop design.
Method
Participants
Data were colleted from 30 children, with ages ranging from 10 to 15 year old (M=12.5 years), all located in Nassau County, NY. Demographically, the children were predominately Caucasian, from middle to upper-middle class socioeconomic status, attending public schooling. These children were paid for their participation in this experiment, a compensation equivalent to about $2 per participant.
Design and Procedure
This experiment was a with-in group design. The children were family and friends of the author, Lysa Alvino. The test was given in a home office, and the participants were tested individually by the experimenter, Lysa Alvino. The present experiment was conducted over a time frame of three days. The experimenter first tested the participants with Test A, which consisted of 18 rows by 3 columns of colored rectangles. Participants were asked to state the color of each rectangle from left to right, row by row. The experimenter held a sheet of paper to cover the rows beneath the row currently being read, as not to confuse the participants with the conflicting stimuli that was not relevant at the time. Time was taken with a stop-watch; time started at the beginning of the test, and was stopped after the last color was stated. When the participant had an incorrect response, they were asked to repeat the correct response.
After completing Test A, they were then given another timed test called Test B. Test B contained animal words in printed in different colored ink. There were 18 rows by 3 columns of colored animal words. Participants were instructed to state the color of the word, but not the read word, row by row. Again, the experimenter held a sheet of paper to cover the rows beneath the row currently being read, as not to confuse the participants with the conflicting stimuli that was not relevant at the time. Both tests were timed to see how long it would take the participants to say the color of the word with the method described above. Time was recorded by milliseconds.
Materials
Test A (part one) was a sheet of paper containing randomly colored rectangles and Test B (part two) were animal words, typed in various random colors. Also included was a blank sheet of white paper to cover the rows not being read at the time. To collect data, the experimenter used a data collection sheet with the participants’ names as well as two columns beside each name, one to record the time for Test A, and the other to record the time for Test B.
Results
A within-subject paired sample t-test was used to draw results between the time for Test A (the colored rectangles), and the time for Test B (the colored animal words). As predicted, Test B had a longer reaction time than that of Test A. Participants stating the colors of the rectangles during Test B (M=77.42, SD=24.53) took significantly longer, t (29) = -11.44, p=0.0001, than stating the colors of the animal words in Test A (M=52.48, SD= 20.05).
Discussion
As stated in the hypothesis, middle class American adolescents are natural readers; therefore, printed words caused interference when the children were asked to disregard this information. They were unable to completely tune out the printed stimuli, and instead delayed responding to the task.
This was expected because of the prior experiment, the original Stroop test. The problem of interference, as described in this experiment, can be summarized by the phrase “Stroop Effect”. The participants in this experiment were significantly affected by the competing information.
References
Alansari, B. (2004). The Relationship Between Anxiety and Cognitive Styles Measured on the Stroop Test. Social Behavior and Personality. 32(3), 283-294.
Besner, D. & Roberts, M.A. (2005). Stroop Dilution Revisited: Evidence for Domain-Specific, Limited Capacity Processing. Journal of Experimental Psychology: Human Perception and Performance. 31(1), 3-13.
Bud, D. & Masson, M. Lalonde, C.E. (2006). Cognitive Control in Children: Stroop Interference and Suppression of Word Reading. Psychological Science. 17(4), 351-357.
Kaufmann, L. & Nuerk, H.C. (2006) Interference Effects in a Numerical Stroop Paradigm in 9-to 12 year old Children with ADHAD-C. Child-Neuropsychology. 12(3), 223-243.
MacLeod, Colin M. (1991). Half a Century of Research on the Stroop Effect: An Integrative Review. Psychological Bulletin. 109 (2), 163-203.
Stolz, Jennifer A. & McCann, Robert S. (2000). Visual Word Recognition: Reattending to the Role of Spatial Attention. Journal of Experimental Psychology: Human Perception and Performance. 26(4), 1320-1331.
