Experiment 1: The Effect of Interfering Color Stimuli Upon Reading Names of Colours
Methods
Two tests would be taken to demonstrate the interference by color stimuli in reading names of color.
Best services for writing your paper according to Trustpilot
In both tests, subject would respond to a color name by pressing its corresponding key on the keyboard. (i.e. pressing Z for “red”, X for “green”, C for “blue”, V for “brown”, and B for “purple”) Subject is required to respond correctly as quick as possible. Subject is given 20 practice trials before start of the test.
After familiarized with the responses setting, subject would take the first test to respond to color names without color stimuli. Color names in black color will be appeared randomly with same frequency, and no same color name would appear successively. This is a test known as “Reading color names printed in black” (RCNb) (Stroop, 1992).
After responded 100 times to color names in black, subject is asked to respond to a color name in a color incongruent to which it names. For example, the word “red” which appears blue, brown, green or purple would require subject to recognize and respond to as the word “red”. The appearances of color stimuli are randomized so as to avoid any regularity of occurrence and each color would appear by an equal number of times. No same color word would appear successively to avoid regularity of occurrence. The test is known as “Reading color names where the color of the print and the word are different” (RCNd) (Stroop, 1992).
Instructions for each test would appear before it starts. A cue is appearing between trials to help subject on maintaining focus to the center of screen. 12 subjects have made less than 4 uncorrected responses on the RCNd test despite of instructions. There are 10 subjects made less than 4 uncorrected responses in the RCNb test. A maximum of 4 errors is allowed for every subject.
Subjects
Twenty undergraduate students were recruited in this experiment. The total number of subjects is comprised of 4 males and 16 females. Each subject made 200 reactions on each test.
Results
The means (m), standard deviations (i??), differences (D), probable error of the difference (PEi??), and the reliability of the difference (D/ PEi??) by sexes and the whole group are presented in table I.
Observation of the table shows that the reaction time for responding to 100 color names in incongruent colors is 0.2 seconds longer than that for responding to color names in black (an increase of 13%). The means for the sex groups show dramatic differences. Subjects in the Male group had significant delays in responding to interference. According to the means and standard deviations of their response times to stimuli, the interference factor has made significant increase in the variability for the whole population and for the male group. The effect by interference is, however, not observed among the female group.
Table I
The Reaction Time in milliseconds for Reading One Hundred Names of Colors presented in Incongruent Colors and for One Hundred Names of Colors presented in Black
RCNd
RCNb
D
PEi??
D/ PEi??
Sex
No. of Ss
m
i??
m
i??
Female
16
1157.8
55.9
1090.8
58.5
67
0.2
314.2
Male
4
2053.1
320.5
1424.5
209.3
628.6
16.1
39.0
Male & Female
20
1336.9
392.0
1157.5
168.4
179.3
0.7
249.0
Experiment 2: The Effect of Interfering Word Stimuli Upon Naming Colours
Methods
Two tests would be taken to demonstrate the interference by word stimuli in naming colors.
In both tests, subject would respond to a color name by pressing its corresponding key on the keyboard. (i.e. pressing Z for “red”, X for “green”, C for “blue”, V for “brown”, and B for “purple”) Subject is required to respond correctly as quick as possible.
To familiarize with the responses setting, Subject is given 20 practice trials before start of the test. Subject would be asked to respond to arbitrary characters in random colors. Subject would be asked to name the color and input correct response according to instructed response settings. After practice trials, subjects would perform the first test. Each color will appear in equal number of times, and no same color would succeed itself to avoid regularity of occurrence. This is a known as “Naming color test” (NC) (Stroop, 1992).
After responded 100 trials in NC, subject is then asked to name the color names presented in colors incongruent to which they name and respond to stimuli by input the corresponding keys. For example, the word “red” which appears “blue” would require subject to ignore the meaning of word and respond to stimuli as “blue”. The appearances of word stimuli are randomized so as to avoid any regularity of occurrence and each word would appear by an equal number of times. No same word would succeed itself. The test is known as “Naming color of word test where the color and the word are incongruent” (NCWd) (Stroop, 1992).
Instructions for each test would appear before it starts. A cue is appearing between trials to help subject on maintaining focus to the center of screen. All subjects have made a total of 18 uncorrected responses on the NCWd test despite of instructions. A maximum of 4 errors is allowed for every subject. There are 7 uncorrected responses left by 4 subjects in the NC test.
Subjects
Twenty undergraduate students were recruited in this experiment. The total number of subjects is comprised of 6 males and 14 females. Each subject made 200 reactions on each test.
Results
The means (m), standard deviations (i??), differences (D), probable error of the difference (PEi??), and the reliability of the difference (D/ PEi??) by sexes and the whole group are presented in table II.
Mean time for naming the colors of 100 words in incongruent colors has increased for 209.5 milliseconds (an increase of 13%). The means for the sex groups show significant differences. Males had poorer performance in both tests compared to that of females. The difference of 209.5 milliseconds is 0.33 standard deviation units in terms of the NCWd test or 0.29 standard deviation units in terms of NC test. Although delay in the mean time for responses to NCWd test is observed among females, the differences of mean time observed in terms of variability of the groups shows that no significant effects on population by introducing interfering word stimuli.
The large overlapping area by comparing figure 2 & 3 indicates no much interference effect on the response of naming colors.
Table II
The Reaction Time in milliseconds for Naming One Hundred Colors presented in Arbitrary Characters and presented in Words which Name other Colors
NCWd
NC
D
PEi??
D/ PEi??
Sex
No. of Ss
m
i??
m
i??
Female
14
1480.8
402.4
1200.5
364.9
280.3
1.86
149.94
Male
6
2604.5
34.2
2560.2
59.1
44.4
0.67
66.04
Male & Female
20
1817.9
624.7
1608.4
707.6
209.5
2.65
78.97
Discussion
The interference of color stimuli is slightly significant by the result of Experiment 1 but the interference of word stimuli is not significant. Sex differences on mean time are significant in both tests. The insignificance in results may be due to subjects’ novelty to the responding method. The improvements in the reaction time along the experiment have counteracted the interfering effects by stimuli. Color words and word stimuli in a language other than subject’s mother tongue may inhibit the significance, since reaction time to a stimulus in foreign language can depend on subject’s proficiency in that language.
Due to difficulties in recruiting, 12 participants were given experiment 1 and experiment 2 sequentially with only 2 to 3 minutes break in between experiments. Their fatigue states may have contaminated the results. This worth consideration and improvement in future experiment.
Reference
Stroop, J. R. (1992). Studies of Interference in Serial Verbal Reactions. Journal of Experimental Psychology, 121(1), 15–23.
