1. Module 1 Experimental Psychology Guided-Inquiry Learning
THE STROOP EFFECT
Module 1
Experimental Psychology Guided-Inquiry Learning
Module 1: The Stroop Effect
© , Dr. A. Geliebter & Dr. B. Rumain, Touro College & University System

2. Motivation
Suppose we have two signs. One sign has three blue Xs. The second sign has the letters R-E-D written in blue ink.
In which case is it easier to say that the color of the ink is blue?
A question like this motivated Stroop in 1935 to do his famous experiments on interference in color naming.
XXX
RED

3. Activity 1: Experiment 1 Method:
Subjects: Subjects were college students.
Procedure: Subjects were asked to perform two tasks:
(1) To name the colors of solid squares presented to them.
For example, a subject is shown a red square
and is supposed to say “red”. This is the naming color (NC) test. (This is condition NC in Table I below.)

4. Activity 1: Experiment 1
(2) To name the color of the ink in which a word was printed. For example, when the word “red” was written in blue ink, the subject was supposed to say “blue”: In the table below, this condition is referred to as NCWd, which stands for “Naming test where the color of the print and the word are different.”
RED

5. Results The results of this experiment are given in Table I below.
“n” refers to the number of subjects.
“NCWd” refers to the condition where the color of the print and the word are different, and the subject should name the color of the print.
“NC” refers to the condition where the subject is shown solid-colored squares and should name the color of the square.
“σ ” refers to the population standard deviation.
“D” refers to the difference in the mean reaction times for NC and NCWd tests.

6. Table I
Mean time (in seconds) for naming 100 colors presented in squares and printed in words naming other colors
What are some questions we might ask ourselves? Write down your team’s questions on the handout.
Sex n
NCWd σ NC D
Male 29
111.1
21.6
69.2
10.8
42.9
Female 71
107.5
17.3
61.0
10.5
46.5
Male and Female
100
110.3
18.8
63.3
47.0

7. (Write down your team’s answers on the handout.)
Table I
Mean time (in seconds) for naming 100 colors presented in squares and printed in words naming other colors
Here are questions we might ask:
1) Is there a difference between males and females in the time it takes to perform the NC and NCWd tests?
2) Is the difference significant? How can you tell? Which statistical test would you use?
(Write down your team’s answers on the handout.)
Sex n
NCWd σ NC D
Male 29
111.1
21.6
69.2
10.8
42.9
Female 71
107.5
17.3
61.0
10.5
46.5
Male and Female
100
110.3
18.8
63.3
47.0

8. Activity 2: Experiment 2
Stroop used five colors: red, blue, green, brown, and purple.
He made a list of color names. No word was printed in the color that it named.
So a word in red ink would never say “Red”. It would always say a color other than red to create conflict when the subject had to name it. For example, we could have the following:
What is the conflict created? Why is there a conflict? (Write your answers on the Team handout. )
PURPLE

9. Table II
Below in Table II are the mean reaction times (in seconds) showing how long it took for the subject to read RCNd and RCNb.
RCNd = Reading color names where the color of the print and the word are different
RCNb = Reading color names printed in black ink
Mean time (in seconds) for reading 100 names of colors printed in colors different from that named by the word and for 100 names of colors printed in black
Sex N
RCNd σ
RCNb D
Male 14
43.20
4.98
40.81
4.97
2.41
Female 56
43.32
6.42
41.04
4.78
2.28
Male and Female 70
43.30
6.15
41.00
4.84
2.30

10. (Write your answers on the Team Handout.)
Table II
Mean time (in seconds) for reading 100 names of colors printed in colors different from that named by the word and for 100 names of colors printed in black
Questions:
What can you infer from the table?
Is there a difference between males and females in the time it takes to perform the RCNb and RCNd tasks?
Is it significant? How can you tell?
Which statistical test would you use?
(Write your answers on the Team Handout.)
Sex N
RCNd σ
RCNb D
Male 14
43.20
4.98
40.81
4.97
2.41
Female 56
43.32
6.42
41.04
4.78
2.28
Male and Female 70
43.30
6.15
41.00
4.84
2.30