The aim of my experiment is to prove Stroops theory, and find out if interference occurs when participant is asked to identify colour words in different coloured ink.
My hypothesis is:
‘There is a meaningful difference in the amount of time taken to identify colour words written in the same coloured ink, than in identifying colour words written in different coloured ink’
The null hypothesis would be:
‘There is no meaningful difference in the amount of time taken to identify colour words written in the same coloured ink, than in identifying colour words written in different coloured ink’
Design.
To prove my hypothesis I chose to replicate the experiments conducted both by Stroop and Sheibe, Shaver and Carrier in a combined effort. The experimental design that I chose was the Repeated Measures Design, which was where one participant would be used for all parts of the study.
The advantage of this type of design would be that since the same person is used in all parts of the experiment there are no problems with individual differences. The design also works well with controlling participant variables. Fewer participants would also have to be used.
The disadvantage is that there may be occurrence of fatigue and practice effects, and also the participant may develop Demand Characteristics where he/she might tend to do what is expected of them.
Variables
Independent variable: Whether or not the colour word was typed in the same colour ink.
Dependent Variable: The amount of time taken to identify the colours that the words were written in.
Extraneous Variables: this experiment did consist of a considerable amount of extraneous variables as it took place in an environment that was teeming with students. Even though the participants were taken into a relatively quiet place E.g. an empty classroom, some amount of noise was always present, and some areas were considerably noisier than others. Thus, the results of the experiment may be subject to change if the experiment was conducted under laboratory conditions with strict controls on extraneous variables.
Target Population
The target population was boy and girl students of Asian International School.
Sampling
The method sampling that I used was Opportunity Sampling, meaning I asked people whom I came across. This method of sampling was easy to execute and was less stressful.
Ethical Issues
As in every psychological experiment there were certain procedures I had to observe to ensure that I was not violating the rights of my participants. There was a briefing at the beginning of the experiment and a debriefing and the end of it. This was done verbally on my part. I told the participants that their names would not be used and strict confidentiality would be maintained. I also told them that participation was purely voluntarily and that they had the right to withdraw at any point during the experiment. I did not give full details of the study but gave sufficient information to get my point across.
In addition to this I also had to gain informed consent, and whilst most of this obtained by the briefing and the debriefing, a clear explanation of the objectives of the experiment was given.
Procedure
In order to successfully conduct my experiment, I needed a few things. One was a list of colour names in the same coloured ink (list A), a list of colour names in different coloured ink (list B), a result sheet on which to record my data and a stopwatch.
I then began to find participants using opportunity sampling. After the participant was briefed, I first handed he/she a list of twelve words written in the same colour ink. After recording the amount of time taken for the participant to identify the colours out loud, I then handed them the second list. After recording the timings for this as well I explained to them the objectives of the experiment. Then, I gave each of them the opportunity to withdraw if they so wished. The average time of each set of timings was then found out.
The results are illustrated on a bar graph as follows:
Key: Series 1: amount of time taken for list A
Series 2: amount of time taken for list B
Verbal Summary
My results table, which is in the appendix, and the average times clearly show that a longer amount of time was taken to identify colours in list B than in list A. in addition to which the lowest timing was achieved when the participant was reading list A (3.38 secs) and the highest timing was achieved when reading list B (25.34 secs). The Bar Graph above clearly shows the contrast in the amounts of time taken over both lists, with there being over a hundred percent increase when reading list B in some cases. Also it is worth taking note that all mistakes that were made, were made only whilst participants read list B. So it can be said that the participants found it easier to read list A than List B.
Discussion
Looking at the results table I think that my hypothesis was proved to be accurate, and Stroops theory is acceptable. Thus the null hypothesis can safely be rejected. This also proves that the theory of Sheibe, Shaver and Carrier can be accepted, and that interference does occur via automatic processing.
However I also feel that certain improvements could have been made on the study. The fact that I used the Repeated Measures design shows that participants may have developed fatigue, practice effects or demand characteristics. Had I used an Independent Groups design, perhaps my study would have been more accurate.
As I have already stated, the noise levels of my school may have been an interference all on its own, so thus, I had no strict control over my extraneous variables, had I had this, perhaps my results would have been different.
An interesting thing that I found when doing the experiment was that the participants felt that it was some sort of exam and that they had to perform well. I noticed that due to this, the participants tended to try and run through list B as fast as possible, already confident with their performance when reading list A. This lead them to become flustered and confused, which I felt made them take longer. If they have been calm and collected, perhaps they would have achieved lower timings for both lists. Perhaps if I had shown them the harder list first, their performance may have been different.
As far as generalizability is concerned, the fact that my target population was students from my own school may make the study a little bit harder to generalize. As we all grew up in the same environment, and some of us have known each other since childhood, we may think in the same way, even though we may not realize it. So perhaps if my target population had been larger, and I had more time to carry out this study, then maybe my study would have been more accurate.
I could have also used Random Sampling to reduce bias in my study, which also would have made my study better.
Conclusion.
I am happy with the results of my study, but I feel with a few modifications the study could have been more accurate. But overall, my hypothesis was proved, and automatic tasks do interfere with other simultaneous tasks.
Appendix
Results sheet
References.
Psychology approaches and methods- Christine Brain
J. Ridley Stroop
