(PDF) Replicating the Stroop Effect

Running head: STROOP EFFECT
STROOP EFFECT
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2STROOP EFFECT
Title
Stroop Effect
Abstract
The aim of the experiment is to find out if participants are slower in reading aloud the names of
the colours in an incongruent colour name task in comparison to a congruent colour block task.
20 participants within the age range of 21-35 years of age were taken for the experiment and
were assigned randomly to the two groups and therefore it was a within-participant experiment.
The results obtained suggested that participants did take longer to name colours in case of the
incongruent task than the participants in the congruent ask group.
Introduction
Stroop (1935, as cited in MacLeod, 1991) conducted experiments involving colour naming and
word reading. He demonstrated the difficulty of suppressing the automatic process of reading
when naming ink colours, and this has been coined the Stroop effect. As outlined by MacLeod
(1991), in a typical Stroop task, participants are instructed to state the colour of ink used in
stimuli, where the stimuli used are either solid squares of the ink (e.g., a red square) or the names
of colours which are different (i.e., incongruent) from the ink colour used (e.g., the word “blue”
printed in red ink). In the Stroop task, participants took longer to state the ink colour when it was
incongruent to the colour name presented than when it was presented as a solid square. In other
words, it took a longer time to say “red” to the word blue printed in red ink than to say “red” to a
red square (Cothran & Larsen, 2008; Zurrón, Ramos-Goicoa, & Díaz, 2013).

3STROOP EFFECT
Based on past findings, the present study attempts to test the Stroop effect by using congruent
colour squares and incongruent colour names. The experimental hypothesis predicts that
participants will be faster in naming the colours when supplied with congruent colour squares
than when supplied with incongruent colour names while the null hypothesis predicts that there
will be no difference in the time taken to name the colours between the congruent colour squares
condition and the incongruent colour names condition.
Method
Design
The experiment employed a between participant design. The independent variable was the stroop
task with congruent colour squares and incongruent colour names and the dependent variable
was reaction time.
Participants
20 participants within the age range of 21-35 were randomly selected and randomly assigned two
the two experimental groups. Average age of the participants was 27.
Materials required
Consent form, participant instructions, stroop test materials for congruent colour blocks and
incongruent colour names, stopwatch, pen.
Procedure
The participants were made to sit and were handed stapled sheets of the consent form,
instructions for the test and the stroop test materials. They signed the consent form, read the
instructions and when they seemed ready, they were instructed to ‘flip the page’ and the test was
started. The time taken by the participants to say each colour aloud were recorded and the total

4STROOP EFFECT
time taken was calculated. The time scores of the participants for both the tasks were made into
a table and the required calculations were carried out.
Results
Table 1 shows the mean response times for the congruent and incongruent conditions.
The average time taken by the participants for congruent colour block condition is 20 seconds
and that for incongruent colour names condition is 43 seconds.
Table 1: Mean scores on the Stroop test
Stroop test Response time (in seconds)
Congruent colour square condition 20
Incongruent colour name condition 43
Results of an independent sample t-test show that there was a significant difference between the
mean response times of the participants in the congruent colour squares condition and
incongruent colour names condition (t(18)= 14.45, p < .05).
The experimental hypothesis can therefore be accepted and we reject the null hypothesis.
Discussion
The aim of the experiment was to find out if naming the colours of an incongruent colour
name task would be slower than that of a congruent colour square task. The experimental
hypothesis that we made stated that reaction time for naming the colours would be faster in case
of the congruent colour squares in comparison to incongruent colour names. This hypothesis is
accepted in the present experiment, as the average time taken by the participants for the
incongruent task was 43 seconds and that in case of the congruent task was 20 seconds and
according to the t values a significant difference between the two means were found, t(18)=