One variation of Stroops study was conducted by Flowers (1979). He found that people struggle to resist saying the numbers that make up each row rather that counting the numbers, this is because number recognition is much more automated relative to number counting.
Aim
The aim of this investigation is to find out whether there is a significant difference in the time taken to name common noun words printed in different colours, for example the word house printed in green ink, compared to colour words printed in different colour inks, for example the word red printed in the colour blue. RED
Hypothesis:
Directional (one tailed)
Participants from the age of 15-20 will take significantly longer to name the ink colours of twenty colour words presented in conflicting ink colours compared to the time it will take for them to name all the twenty common noun words presented in different colours.
Null hypothesis
There will be no difference between naming the colour words presented in conflicting colours and naming the common nouns presented in different colours.
The level of significance is 0.05. If that level is found then investigation can be accepted. This then makes the directional hypothesis acceptable and the null hypothesis unacceptable.
Method
Design:
To support the hypothesis, Stoops experiment was replicated. A laboratory experiment was chosen. This is because a laboratory experiment has a high level of control against confounding variable and conditions can easily be manipulated. Repeated measures design was used. This is where all the participants would be used for each condition of the study. (E.g. noun words and colour words)
The advantages of repeated measures design are that there are no problems with individual differences. Also fewer participants would have to take part. The disadvantage is that fatigue and order effects may occur. Also demand characteristics may be an issue. To minimise this, counterbalancing was used. This involves halving the participants into two groups. One of the groups will do condition A first. This is naming the noun words first and then colour words, and the other group will do it vice versa. (Condition B)
The independent variable in this investigation is the variable the experimenter manipulates. This is the condition of colour words and noun words. The dependant variable is the time taken to name the noun words and colour words correctly
Controls:
There could be many confounding variables, also known as extraneous variables. Some of the variables were successfully controlled and some were not. Variables that were successfully controlled include.
- Standardised instructions. This is where the experimenter explained the instructions the same way to every participant thereby reducing experimenter bias.
- Participants were all naïve. This made sure that no participants had ever heard of the Stroop effect which could affect their performance
- The stop watch was used to time participant’s performances in each of the conditions.
- All participants were inspected to have good eye sight and more importantly checked for colour blindness. This made sure that no participants were having to take more time due to lack of visibility.
- All participants were made sure that English was their first language and if there English was fluent. This made sure that no participant was dyslexic which would increase the time taken to name the colours and nouns.
All these confounding variables were controlled in order for the results to be valid. All these extraneous variables could affect the participant’s performances in time.
Sample:
The researcher was made sure that adequate knowledge was required to replicate Stroops original study. A 17 year old male was the researcher. Ten participants were selected in total with specific ages between 14-18 years and 20-35. Opportunity sample was used. This made is convenient for the researcher because the random sampling will require to much time. Some of the participants were from a secondary school on 6th from students and household relations. All participants were made sure to have no background knowledge on Stroop or the Stroop effect otherwise this will affect the results. There was no biasness to any sex.
Materials:
The materials used in this experiment were the two lists. There were the twenty common noun words presented in different colour inks. The other list was twenty colour words presented in conflicting colours. For a copy of the two lists (see Appendix 1). A pilot study took place to highlight any issues with the list structures, visibility of colours, unknown colours or any unknown or uncommon nouns. Our first lists had the noun and colour words in two columns, each list on a different A4 paper. The participant struggled on a few of the colour words since they were not distinctively clear of to which colour it was. Also the participant found it hard to scroll down two different columns on the same A4 paper of the two lists. After the pilot study, a new pair of lists was made with more common colours and each of the lists in one column of the paper. Also a stop watch was used to measure the time taken for each participant to successfully complete the two lists. This was measured in milliseconds at first but either rounded down or up into whole seconds.
Procedures:
Instructions were given to all the participants. These were standardised to make sure participants did not hear anything incorrect which will affect their understanding. Inaccurate results could occur because of this and can question the validity of the experiment. The full standardised instructions can be seen in (Appendix 2)
Different candidates were asked if they wished to participate in the experiment. A briefing was given to explain the study and for any questions to be asked. A consent form was also filled out. Assure the participants that intelligence is not being measured and that the participants can withdraw any time. After completion of the task a debriefing must take place informing the participant about the true nature of the study.
The first five participants were selected. They had to name the nouns words first and then the colour words and the other five had to name the colour words first and then the noun words. This made sure counterbalancing was used to minimise order affects. To view the two lists in full (see appendix two). When the stopwatch was ready I asked them to start naming the colour of the ink on both lists. One word at a time was revealed to them and if they named the wrong ink colour then the next word would not be revealed to them until they responded correctly. After they completed their time was recorded for both lists. In order for the experiment to be significant and valid, a Wilcoxon Matched Pairs Sign Rank Test was used with all the raw data to see if the results support the hypothesis and whether the data is significant. This test is suitable for my data as it is a test of difference. Also the design was repeated measures. It is used as an interval level which can be converted to ordinal level for this experiment.
This statistical test is suitable for my data as it is a test of difference, suitable for data gained from a repeated measures design. It can be used with data on an interval level of measurement, which is then converted to an ordinal level for the purpose of the test
Results:
The aim of this investigation is to find out whether there is a significant difference in the time taken to name common noun words printed in different colours, for example the word house printed in green ink, compared to colour words printed in different colour inks, for example the word red printed in the colour blue. RED. The independent variable is the variable being manipulated i.e. noun words and colour words. The dependant variable is the outcome which is the time taken to name the noun words and colour words.
The data was set in interval. This was collected by timing how long it took for all the participants to name out the two lists. The time was rounded into whole seconds. The average times are given below. To see the raw data and each participants performance then see (appendix 3). To see all the standard deviation calculations, then see (appendix 4)
As you can see from the table and graph, it took participants much more longer to successfully name the colour words list than the noun words list. This supports the alternate hypothesis that participants from the age of 15-20 will take significantly longer to name all the twenty colour words presented in conflicting ink colours compared to the time it will take for them to name all the twenty common noun words presented in different colours. The standard deviation shows variance around the average. The standard deviation is smaller in the noun list which shows less individual differences.
To ensure the findings are significant for the number of participants that have been used, a Wilcoxon matched pairs sign rank test will be used. This test finds the difference between two sets of data. This is test is also used for data which is interval. To see the Wilcoxon match pairs sign rank test table then see (appendix 5)
Observed value = 0 Critical value = 10
The Wilcoxon Matched Pairs Sign Rank Test shows that my results were significant. This in turn means that the alternate hypothesis is accepted and the null hypothesis is rejected. This is because the observed value is smaller tan the critical value.
Discussion
The psychological research conducted by Stroop support the results of this experiment. The participants reading levels were autonomous. This meant that they had to take longer to name the ink colour the word was printed in and ignore what the actual word is. This relates to the theory of interference.
The results do support the Psychological research, conducted by Stroop. The observers have automatized the process of reading. Thus, the colour names of the words are always processed very quickly, regardless of the colour of the ink. On the other hand, identifying colours is not a task that observers have to report on very often, and because it is not automatized it is slower. The fast and automatic processing of the colour name of the word interferes with the reporting of the ink colour. These findings as a result support Stroop. It also supports Schneider and Shiffrin’s theory on interference.
All ethical considerations were taken into account before this experiment took place. These include:
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Confidentiality: This ensures each participants results are not to be shown to anyone else and that the results remain anonymous
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Withdrawal: This ensures that all participants at any time have the right to withdraw from the experiment thought their own wish.
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Consent: This ensures that all participants must have given their consent to participate in the study
Due to the nature of the study, informed consent was not given and as a result, the participants were deceived. If they knew the nature of the study, then they will alternate their behaviour and distort the findings. However they were debriefed fully after the experiment and were told about the investigation.
However this experiments internal validity is questionable. The task of having to name colour words and noun words is not an everyday task. Also this was a laboratory experiment with controlled conditions which may have affected the results.
Also the reliability could be a problem. Not all the participants showed the Stroop affect. This means that some people are not affected that much by interference and can ignore autonomous processing.
The research was conducted using opportunity sample. A limitation of the experiment would be the population validity; this study cannot be generalised to a greater population. To counteract this, random sampling could be used. This could be done by randomly selecting participants electronically using computers. To improve the validity, stratified random sampling could be used. This is where selection of participants is chosen from specific groups.
Another issue with the study is that consciously or unconsciously the researcher may have revealed the words slower or fast after each correct response was given. This will affect the overall time of the performance and hence affect the overall findings. To solve that problem, a computer could reveal each word after a correct response is identified.
Stroop Effect Test Colour List: Nouns
Appendix 1
Shoe
Paper
Table
Sun
Pencil
Hammer
Car
Chair
Brick
Handle
Gun
Sky
Water
Guitar
Dog
Watch
Book
Bus
Tree
Rain
Stroop Effect Test Colour List: Colours
Red
Yellow
Yellow
Green
Orange
Purple
Grey
Red
Blue
Orange
Green
Black
Purple
Yellow
Black
Brown
Brown
Blue
Pink
Pink
Appendix 2
There are two pieces of A4 paper. One list in the nouns and the other is the colour words. They researcher will say “go” and will start the stopwatch. One word will be revealed at a time and each time a successful response is given, another word would be revealed. The next word would not be revealed until a correct response is given. After completion of the first list, the time will be recorded and the same will happen with list two.
Any questions
Appendix 3
Appendix 4
Appendix 5
Wilcoxon Matched Pairs Sign Rank Test
Observed value = 0 Critical value = 10
References
PSYCHOLOGY A NEW INTRODUCTION FOR A LEVEL 2ND EDITION RICHARD GROSS ROB MCILVEEN
PSYCHOLOGY FOR A2 LEVEL COLLINS CARDWELL CLARK MELDRUM
MacLEOD, C.M. (1991) Half a century of research on the Stroop effect: an integrative review. Psychological Bulletin
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