A Comprehensive Analysis of the Stroop Test in Psychological Research

This report presents an analysis of a Stroop test conducted on 21 participants aged 19-44. The study investigated the Stroop effect, measuring response times in congruent and incongruent conditions. Results indicated significant Stroop interference, with longer response times in the incongruent stages. The analysis explored the impact of age and gender, revealing a correlation between increased age and slower response times in the incongruent test. While gender showed no significant difference in the first incongruent test, females had significantly greater response times than males in the second incongruent test. The study utilized statistical methods, including t-tests and linear regression, to analyze the data and test the hypotheses. The report discusses the findings in the context of existing literature and identifies limitations, such as the small sample size and limited age range of participants, suggesting areas for future research.

Running head: PSYCHOLOGICAL RESEARCH METHODS
PSYCHOLOGICAL RESEARCH METHODS
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Table of Contents
Abstract......................................................................................................................................2
Introduction................................................................................................................................3
Method.......................................................................................................................................4
Participants.............................................................................................................................4
Materials...............................................................................................................................10
Procedure..............................................................................................................................11
Results......................................................................................................................................11
Discussion................................................................................................................................14
Reference..................................................................................................................................16

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Abstract
The study investigated the effectiveness of a Stroop test on 21 individuals aged
between 19 and 44 years. It was conducted in two parts and both the parts were found to
invoke significant Stroop effect with response time being significantly greater in the
incongruent stages of both. It was seen that as age increases, so does time to respond in the
incongruent test stage. Again, although gender was found to be insignificant in the first
incongruent test, females had significantly greater response time than males in incongruent
with D stage.

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Introduction
The Stroop test is a test of neuro-cognition which has immense application in the field
of psychology for both experimental studies and clinical studies (Singh & Sachdeva, 2014).
The objective of the test is to test a person’s ability to simultaneously process colour and
shape or language.
In the Stroop test the participant is asked to read a set of words which are names of
colours that are type of depicted in the same coloured ink and the delay in processing time is
recorded called congruent stage. Again the individual is asked to read from a list of words
which are coloured in ink which is not the same colour as what the word reads called
incongruent stage. It is generally seen that there may be delay in processing the correct
answer in incongruent stage (Scarpina & Tagini, 2017). This effect is known as the Stroop
effect and such interference administered to the cognitive process is known as the Stroop
interference. This test was developed and proposed by John Ridley Stroop in 1935 in the
Journal of Experimental Psychology (Saeed & Tajne, 2017). This test has been used time and
again to study the capability of an individual to resist cognitive interference.
. Kiyonaga & Egner(2014) identified working memory(WM) to be comparable and
mimicking the way the stimulus in Stroop test works. Drawing on that , Zinke(2014) had
utilized the instrument to measure working memory in older adults while studying the impact
of working memory training on adults aged 65 to 95 years. The difference in the naming
times between the incongruent and congruent stages was used as the measure of cognitive
ability. The study had found that with training the performance on the test can be consistent
over a broad range of ages. This was again addressed by Grégoire, Perruchet, & Poulin-
Charronnat (2015) but using reading of musical notes as stimulus, where they found both age
and practice as relevant factors, such that, with age and practice cognitive control increases.

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Zimmermann et al.(2015) in her study of effect of age and educational background on the
normative data of Brazilian people had used the test as one of the indictors of cognitive
abilities. The study had taken individuals grouped as per age as a younger and an older group
and identified that age has a significant effect on the colour and word naming timing of the
Stroop test. Malek & Amiri(2015), had used the test as an instrument to study the executive
brain functions of bilingual Iranian adolescents, their study again corroborated with the
findings of Zimmermann et al.(2015), confirming that the age of their participant had
significant impact on the test however gender failed to have the same impact. Tremblay et al.
(2016), studied older French-Quebec citizens for the relationship of age, education and sex
with that of the results of the stroop test. The study utilized regression analysis and found that
age and education had significant impact and that females were consistently faster.
The study thus proceeds with the following hypothesis:
Hyp 1: The time recorded in congruent stage is less than that in incongruent stage for
all.
Hyp 2: The variable age is correlated with the time in incongruent stage
Hyp 3: The incongruent time for females is less than that of males.
Method
Participants
The data consisted of 21 individuals. The participants of the study were divided into
two groups as per their nationality, that is, either Singaporean or not Singaporean. 5 or 23.8%
were from outside Singapore while 16 or 76.2% were locals.

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Figure 1: Nationality

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12 participants or 57.1% of the total were found to be Chinese,4 or 19% of the total
were Malay, 3 participants or 14.3% were Indian, 1 was from Pakistan and 1 was Eurasia,
which constitutes 4.8% of the total count each.

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Figure 2: Race

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11 of the total participants which is 52.4% of the total were Female and 10 or 46.7%
of the total were Males in the sample.
Figure 3: Gender

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The estimated average age of the sample of individuals was computed to be 25.71
years. The standard error of the mean was 1.536 which being low indicated a good estimate.
The median age value was 23 years and but the mode of age with highest frequency was 20
years. The variation of the data as computed using the standard deviation was found to be
7.037, meaning, most values lie within 18 to 30 years of age. The range is however large at
25 years, with minimum being 19 and maximum is 44 years. Thus the data does have extreme
values. The first quartile has the value 20 years, the media is 23 years and the third quartile is
30 years of age. Then looking at the histogram, it is clear why the distribution of age is
positively or right skewed with frequency being higher towards the ages that are in the 20s
(Creswell & Creswell, 2017).

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Figure 4: Histogram of the Age
Materials
The study had collected data on the results of two Stroop tests and recorded the time
to answer for congruent steps and incongruent steps. The first test measured the time for two
variables “congruent” and “incongruent” which are the time taken in seconds by the
participant to react to the respective scenarios in light if the Stroop test. The variables
“congruent with D” and “incongruent with D” are similarly the times for the second phase of
the Stroop test.

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Procedure
The software SPSS was utilized to analyze the data and statistical tests such as,
descriptive statistical measures of central tendency, variation and frequency distribution, the
paired t-test, the independent samples t-test and linear regression were used for the purpose of
study.
Results
The average time for congruent and incongruent and congruent with D and
incongruent with D is as given in the following table:
The paired t-test testing for the response time of the individuals at the congruent and
at the incongruent stage, taking level of significant to be 0.05, found that there is significant
difference in the response times for the congruent and incongruent stages and congruent with
D and incongruent with D stage as shown below (Ott & Longnecker, 2015):