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INTERNATIONAL BACCALAUREATE EXAMINATION

YEAR

Psychology Higher Level

Internal Assessment

An experiment to investigate the effect of reading incongruently coloured words on the time it takes to process

information

Word Count: 1944

Candidate Number:

Centre Name: Emirates International School – Jumeirah

Centre Number:

Submission Date: 7th February

Abstract

The aim of this experiment was to investigate whether visual interference affects the

cognitive processing speed (in seconds) in naming coloured words. The research hypothesis

states that the mean time to identify the series of coloured blocks will be significantly less

than the mean time required to read the list of incongruently coloured words.

The method used for this experiment involved a repeated measures design The independent

variable was the list of incongruently coloured words and the dependent variable was the

mean time taken to state the colour aloud in the experimental condition (in seconds). The

participants partook in two conditions. Condition 1 was the control where a series of coloured

blocks had to be identified. Condition 2 was the experimental condition where the ink colour

of a series of incongruently coloured words had to be stated. The time taken for each

participant to complete both tasks was recorded. The experiment was counterbalanced, with

the order in which Conditions 1 and 2 were performed being switched after each participant.

There were 34 participants (18 males, 16 females), aged between 16 and 17 years, who were

taken from an opportunity sample of Grade 12 Psychology students and after school CAS

students in Emirates International School Jumeirah.

The results supported the research hypothesis, which depicts that the mean time to identify

the series of coloured blocks is significantly less than the mean time to process incongruently

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coloured words (visual interference has a significant effect on information processing). The

results support Schneider and Shiffrin’s (1977) automaticity model.

Word Count: 254

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Contents Page

Title Page(s)

Introduction 5-7Method Design Participants Materials Procedure

8-108

8-99

9-10Results Bar Graph (Figure 1) Description of Results Analysis of Results

11-12111212

Discussion 13-15

References 16-17Appendices Appendix 1: Standardised Instructions Appendix 2: Condition 1 Appendix 3: Condition 2 Appendix 4: Results Recording Sheet Appendix 5: Debriefing Note Appendix 6: Parents Informed Consent Appendix 7: Participant Informed Consent Appendix 8: Table of Results (1 and 2)

18-2718192021222324

25-26

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Introduction

Reading is a very easy task for most people. However, at a closer look, there are many

perceptual and cognitive factors involved in this task, 1 which when interrupted with visual

interference, can have an effect on the task being undertaken. This study on interference in

perceptual cognition lies in cognitive psychology, which is the study of mental processes.

The aim of this is experiment was to investigate whether visual interference affects the

cognitive processing speed (in seconds) in naming incongruently coloured words.

The Stroop effect is based on the study J. Ridley Stroop (1935) created. Stroop observed that

it takes longer to name the colour of the ink in an incongruently coloured word (the name of

the colour conflicts with its ink colour) than a congruently coloured word (the name and ink

of the colour are the same). Stroop carried out a variety of experiments, recording the time

taken and errors made in each. The different control conditions involved a list of colours in

black ink, a series of coloured blocks, and a list of swastika coloured symbols followed by

incongruent coloured words (the experimental).2 The independent variable was the list of

words he presented as a stimulus to the participants. The dependent variable was the response

time of the participants. Stroop found that participants were slower to perform a task and

made more errors when they were required to visually process incongruent information. In

this study, Stroop’s later experiment (series of coloured blocks) has been used with only the

time recorded.

1 Eyesenck, Michael W.; Keane, Mark T. Cognitive Psychology: A Student’s Handbook. (Psychology Press Limited) pg. 3222 Grivas, John et al. Psychology, VCE. (National Library of Australia) pg. 267

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In the automaticity model, Schneider and Shiffrin (1977) distinguish between controlled and

automatic attentional processing. A controlled process is a task which is new or unique to the

person. It is serial (one activity performed at a time), takes heavy demands on attention,

requires conscious efforts to direct attention towards the task and is slow. An automatic

process is a task which is already learnt. It can be parallel (many activities performed at a

time), makes no demands on attention, does not need conscious direction of attention towards

the task and is fast.3 This implies that when we are presented with a word, the action of

stating its colour is a relatively new task compared to the already learnt behaviour to read just

words. Therefore, reading is seen as the automatic process which interferes with the slower

controlled process of stating the colour.

Norman and Shallice’s (1986) Attention to Action model (ATA) is a theory on executive

control processes and consists of three parts: action schemas, contention scheduling and

supervisory attentional system (SAS). Each action has a schema which is triggered by

different stimuli. In the case of conflicting tasks (reading the word and naming the colour),

reading is a high activation schema which suppresses the action of colour-naming. Due to this

conflict, the same stimulus elicits different responses which can produce errors. The SAS

consciously diverts behaviour to organise and perform this new task in a top-down method,

and inhibits the interfering action schema by actively selecting another. This allows better

capacity for the person to complete the task at hand, but the result is a lag in response time in

order to switch behaviour from the high activation schema (reading) to the new task (colour

name).4

3 Grivas, John et al. Psychology, VCE. (National Library of Australia) pg. 2664 Joshua S. Rubenstein et al. “Executive Control of Cognitive Processes in Task Switching”. Journal of Experimental Psychology: Human Perception and Performance 2001 (Vol. 27, No. 4, pg 764). American Psychological Association (2001)

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H0 – Null Hypothesis

There will be no significant difference in the mean time to read the series of incongruently

coloured words and coloured blocks, or any difference that occurs may be due to chance.

H1 – Alternative Hypothesis

The mean time to identify the series of coloured blocks will be significantly less than the

mean time required to read the list of incongruently coloured words.

Word Count: 604

Method

Design

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A pilot study was carried out before the actual experiment. A repeated measures design was

used as participants took part in both the conditions. This way, all differences between

participants become irrelevant and the results were based solely on the individual’s

performance.5 It was also counter-balanced by half performing the experimental condition

first and half performing the control condition first. This was done to ensure that the

confounding variable of practice improving performance in the task was removed and also to

prevent fatigue from affecting the results. The independent variable was the list of

incongruently coloured words and the dependent variable was the mean time taken to state

the colour aloud in the experimental condition (in seconds). Informed consent was taken from

the participants and parents, and the participants also had the right to withdraw from the

experiment whenever they wanted. Their identities were kept confidential and not noted. All

participants were debriefed after they took part in the experiment and they were told they

could be informed about the results at a later date.

Participants

There were a total of 34 participants, 18 of which were male and 16 were female (roughly an

equal mix of genders). The participants were Grade 12 Psychology students and after school

CAS students from Grade 12 as well. The target population was students from Emirates

International School Jumeirah, averaging between the ages of 16 and 17 years. They were

from a range of different international backgrounds. The sampling used was an opportunity

and invitational sampling, which was convenient and saved time. Participants with informed

consent were taken from their class right before the study instead of keeping them all in one

room to avoid discussion and restlessness from influencing the results.

5 Research Methods and Statistics in Psychology - Coolican, Hugh

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Materials

Standardised Instructions [Appendix 1]

Stimulus sheets (series of coloured blocks and series of incongruently coloured words)

[Appendix 2 and 3]

Stop watch

Results recording sheet [Appendix 4]

Debriefing note [Appendix 5]

Informed consent forms [Appendix 6]

Participant informed consent forms [Appendix 7]

Procedure

Prepare multiple places for the experiment to take place in, which are distant from one

another (as each pair of researchers took one participant at a time to perform the task).

Organise a desk with two chairs on one side (for experimenters) and one chair facing

opposite (for the participant). One experimenter gives instructions and debriefs the

participant. The other times and records responses.

1. From the group of participants, choose at random a participant one at a time to take

part in the study. Participants were experimented upon one by one, while the others

waited.

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2. The participant was invited to take a seat and handed the “informed consent form”.

They were informed of their right to withdraw and assured confidentiality.

3. Keep control condition stimulus sheet [“Condition 1”] (Appendix 2) face down in

front of participant.

4. Follow instruction sheet 1.

5. Collect results.

6. Take back the stimulus sheet.

7. Put experimental condition stimulus sheet [“Condition 2”] (Appendix 3) face down in

front of participant.

8. Follow instruction sheet 2.

9. Collect results.

10. Present participant with debriefing sheet after reading it to them.

11. Allow participant to leave the room and return back to their class

12. Repeat experiment, except with Condition 2 first then Condition 1 (i.e. steps 7-9

before steps 3-5), to counter-balance the study.

Word Count: 550

Figure 1: Bar Graph to Show Mean Response Time and Standard

Deviation for Control and Experimental Conditions

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Results

Description of Results

A bar graph (Figure 1) shows the mean time and standard deviation for participants in the

control and experimental conditions (Appendix 8, Table 1). The results show the mean time

taken in Condition 1 was 8 seconds, compared to Condition 2 which was 3 seconds longer, 11

seconds. The standard deviation for both conditions was found to be 2, which reflects an

equal dispersal in both conditions.

Analysis of Results

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Mean Response Time Standard Deviation0

2

4

6

8

10

12

Control (Condition 1: Series of coloured blocks)Experimental (Condition 2: Incongruent colour words)

A Wilcoxon T (non parametric) test was conducted to determine if the difference obtained

was significant at the 0.05 level of significance (Appendix 8, Table 2). This test was used

because it is at an ordinal level for a related design. The sum of the ranks of the negative

differences is D = 9. The number of participants is 32 (N = 32) because participants F and L

are excluded due to no difference in performance in the two conditions. Using a two-tailed

test, it was found that p<0.002, therefore, the results were found to be better than p<0.05. The

T value is less than the critical level, therefore H0 was rejected and H1 was accepted.

Discussion

The results show that the mean time to say the colour of the blocks (8 seconds) was less than

the mean time to say the colour of incongruent colour words (11 seconds). The standard

deviation for both was 2, showing that most results were close to the average and there was

equal dispersion in both conditions. There was a significant difference in the time taken to

state the colour as is shown by the Wilcoxon T test (p<0.002) and therefore the null

hypothesis was rejected and the research hypothesis was accepted.

Although Norman and Shallice’s model effectively explains the time difference between the

two tasks through the focus on conflicting schemas, Schneider and Shiffrin’s model better

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suits the study. Reading can be seen as an automatic process which interferes with the

controlled process of naming the colour of the incongruently coloured word. Naming the

incongruent ink colour draws more heavily on attentional resources than naming the words,

therefore the response time for participants in the experimental condition was longer.6 The

desired response is the identification of the ink colour which, it is assumed, is a unique and

new task for participants as words are usually automatically read. The conscious effort

required to do the new task rather than read the word automatically, requires mental effort

and awareness, which results in a longer response time. This emphasises the importance of

inhibiting the automatic response in order to carry out the controlled one.7

One of the strengths of this study is the controlled environment used which was prepared

beforehand. This prevented extraneous variables such as noise, weather or intrusions from

affecting the results. However, this ‘artificially created’ environment lacks ecological

validity.

Some of the limitations in this study were that only the time taken to respond was recorded

and not the mistakes made by participants, like in Stroop’s experiment. Taking mistakes into

account would have been ideal in this study, as for two of the participants; there was no

difference in the time taken to complete both conditions. There may have been mistakes in

the experimental condition in an attempt to finish the task as fast as possible (reading the

word instead of stating the colour), which still shows how the automatic response of reading

interferes with the task at hand. Other factors could have influenced participants’

6 “Stroop Effect” <http://psychlops.psy.uconn.edu/psych132/manual/stroop.html>.7 Colin M. Macleod. “John Ridley Stroop: Creator of a Landmark Cognitive Task”. <http://arts.uwaterloo.ca/~cmacleod/Research/Stroopbiog.htm>

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performance on the task such as their intelligence and the amount of effort applied, which

could not have been controlled.

The experiment was restricted in the type of sample taken. An opportunity sample from

within the school makes the results valid only for the target population, and therefore it may

be difficult to generalise to the greater population.

To elaborate on the study and results, the experiment could be carried out by using one word

from each condition successively one after the other (one control, then one experimental

instead of two separate lists) to investigate whether it is the shift of attention to different

schemas or the difference in the nature of the task (automatic or controlled) which results in

the time difference between the two conditions.

The Stroop effect has been used as a medical diagnostic tool for schizophrenic patients, who

display greater interference problems and so a longer response time in contrast with others, as

deficits in attention characterises this condition,8 and for ADHD patients to assess response

conflicts.9

In conclusion, the research hypothesis was supported which shows that the mean time to

identify the series of coloured blocks is significantly less than the mean time to process

8 Avishai Henik and Ruth Salo. “Schizophrenia and the Stroop Effect”. <http://ucdirc.ucdavis.edu/people/papers/henik_salo_BCNR2004.pdf>9 Stins et al. “Heritability of Stroop and Flanker Performance in 12-Year Old Children”. 03/12/04. <http://www.biomedcentral.com/1471-2202/5/49>.

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incongruently coloured words (visual interference has a significant effect on information

processing) and the results support Schneider and Shiffrin’s (1977) automaticity model.

Word Count: 607

References

Books

Cardwell, Michael; Clark, Liz; Meldrum, Claire (2000). Psychology for A LEVEL.

(Pages 368-369). Harper Collins Publishers Limited.

Coolican, Hugh (2004). Research Methods and Statistics in Psychology (4 th edition) .

(Page 65). Hodder Arnold.

Eyesenck, Michael W.; Keane, Mark T (2005). Cognitive Psychology: A Student’s

Handbook. (Page 322). Psychology Press Limited.

Grivas, John; Down, Ross and Carter, Linda (2004). Psychology, VCE (3 rd edition) .

(Pages 265-268). National Library of Australia.

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Online Journals

Henrik, Avishai and Salo, Ruth. “Schizophrenia and the Stroop Effect”.

<http://ucdirc.ucdavis.edu/people/papers/henik_salo_BCNR2004.pdf>. 02/02/10,

11:15 pm.

“Stroop Effect” <http://psychlops.psy.uconn.edu/psych132/manual/stroop.html>.

29/12/2009, 6:17 pm.

Online Websites

Macleod, Colin M. “John Ridley Stroop: Creator of a Landmark Cognitive Task”.

31/01/2010, 4:31 pm <http://arts.uwaterloo.ca/~cmacleod/Research/Stroopbiog.htm>

Stins, John F.; Baal, G Caroline M van; Polderman, Tinca JC; Verhulst, Frank C;

Boomsma, Dorret I. “Heritability of Stroop and Flanker Performance in 12-Year Old

Children”. BioMed Central Ltd. 03/12/04.

<http://www.biomedcentral.com/1471-2202/5/49>. 02/02/10, 11:22 pm

Magazines

Rubenstein, Joshua S.; Meyer, David E.; Evans, Jeffery E. “Executive Control of

Cognitive Processes in Task Switching”. Journal of Experimental Psychology: Human

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Perception and Performance 2001 (Vol. 27, No. 4, pg 764). American Psychological

Association (2001)

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