Stroop identified a large increase on the time taken by participants to complete the NCW tasks, an effect still occurred despite continued practice at each task. There are two theories that may explain the stroop effect. These are:
- Speed of processing Theory: (Appendix A)
- Selective Attention Theory: (Appendix B)
Since the development of the Stroop task, it has utilized the Stroop effect to investigate aspects of such varied psychological disorders as ADHD (), , and . and studies of the Stroop effect have revealed selective activation of the anterior during a stroop task, a prefrontal structure in the brain which is hypothesized to be responsible for conflict monitoring.
The aim of this experiment is to test the stroop effect by investigating whether the time taken to identify the names of colours differs if the colour of the word matches the ink used to spell the word or if it is written in a contradicting coloured ink.
If the color the word is written in matches the word, it will be identified more quickly than if the color the word is written in is contradictory.
There will be no significant difference in the time taken to read colored words written in the same colored ink and the name of colors written in different colored ink.
A one tailed lab experiment (Appendix C).
A repeated measures design as each of the participants will take part in all conditions of the independent variable (Appendix D).
20 people, 10 male and 10 female between the ages 16-60 from a Surrey Sixth form using an opportunity sample (Appendix E). The sample was approached in and around the sixth form block, including the common room, study room and sixth form canteen.
The stroop experimental list is a word list in which each word is a colour name, but always written in a different ink colour. For example, blue would be written in red ink and red would be written in yellow ink. There will also be a control, where the words will match the ink colour that they are written in.
Participants were approached throughout Monday 23rd June 2008, in the Sixth Form Block at School. They were asked to take part in an investigation experimenting the stroop effect (Appendix F). Upon agreeing to participate, they were taken to an empty room where they were given a briefing (Appendix G). They were also informed that the experiment was anonymous (Appendix H). They were then given the (experimental) list of words (Appendix I). The time taken to do this was measured and recorded. The participant was then given the second (control) list of words (Appendix J). Again the time taken to do this was measured and then recorded. Once both sets of words were completed they were debriefed (Appendix K).
- Same room
- Same experiment
- Standardised approach to get participants
- Standardised consent
- Standardised instructions
- Same list of words (One experimental and one control)
- Same researcher/experimenter
- Experiment carried out in the same manner
- Standardised briefing/debriefing
Once consent was given, the right to withdraw was emphasized, and they were also told they could withdraw their results. As they were in an empty room, there was no embarrassment and the results were kept confidential. The participants were briefed and debriefed and any questions they had were answered.
The data will be analysed using a related T test as the experiment was a repeated measures design and there was interval level data.
The graph above appears to indicate the mean time taken in the experimental condition was 25.95 seconds whereas for the control condition is was only 13.44 seconds.
To test the significance of the results a related T test was conducted. This was chosen because the data was interval level data and because the research was testing the significance of the association between the brain and interferences.
The critical value of T, using a 5% level of significance, was 1.729. I found the T value to be 9.52. As the T value of 9.52 exceeds the critical value of 1.729 the results are significant. (Appendix M). This mean the hypothesis is accepted so if the color the word is written in matches the word, it will be identified more quickly than if the color the word is written in is contradictory and the null hypotheses was rejected.
The results show that there is a considerable difference in the time taken to complete the stroop test when the colours are the same as the word rather then when the colour is contradicting to the word. Using the related T test, it was found that the results were significant and so the hypothesis has been accepted.
LIMITATIONS AND MODIFICATIONS:
One of the strengths in this experiment was that there were two experimenters watching over the investigation and measuring the time taken to complete the words. This means that the results are more reliable due to the inter rater reliability meaning that there will be two view points on the results making them more accurate. A further strength is that the experiment was as fair as could be; (Appendix N). Another strength was that the experiment followed the ethical guidelines; (Appendix O).
However, one possible weakness could be that as we only used people from the Fullbrook Sixth form block, the results cannot be generalised. Although we have people of different ages, different genders and different races, they are all from the same area and the same school, and this may be a factor affecting the results. People from different schools around the country, or even people from other countries may be better at identifying the colour of ink without letting the word interfere. This weakness could be overcome by repeating the experiment in other colleges around the country. Another weakness was that many participants wasted time (Appendix P). This may have been as they were not aware of the fact that they were being timed to see how long it took to complete the test. A way to overcome this problem is that before the participant starts the test, you could include in their briefing that they will be timed to see how long they take to complete the test or ask them not to speak until after they have terminated the test. An additional weakness is that the participants took part in both of the two conditions, with means they could not avoid and order effects which may occur. But to overcome this problem, the experimental condition was given first, and the participants were not told of the two different conditions, and were not told that the control words were the same as the colours.
IMPLICATIONS AND APPLICATION
In the experiment carried out by J.R.Stroop, he identified a large increase on the time taken by participants to complete the NCW (naming coloured words). This is what I have found in my own study. The experimental words took longer to complete then the control list of words. This has implications for the presentation of materials to people, as it will have to be well thought out before presented certain things to different people. It also has implications on individual differences. For example people playing on ‘brain training’ type games. Some people will find this easier, but the majority will take more time.
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(A) The interference occurs because words are read faster than colors are named.
(B) The interference occurs because naming colors requires more attention than reading words.
(C) This is where the investigation will be carried out in a laboratory, and the allocation of the participants to the conditions is chosen randomly. It is carried out in very controlled conditions in the experimenters own habitat.
(D)The independent variable (IV) is “the colour and the word written on the paper that will be given to the participants,” this means that there will be one paper with the name of the colour, in that colour and the other will have the name of the colour in a different colour to what is written. The dependant variable (DV) is “the time taken for the participant to name the word on the sheet of paper.”
(E) This is where you use the people who are available at that time, and are easily available for testing.
(F) “Would you like to take part in an investigation we are carrying out regarding the stroop effect?” If they agreed on participating in the experiment, they were taken to an empty room.
(G) “The stroop effect is a test to measure the inference in the brain. So does the colour of the word affect what you see written down on paper.”
(H) “This experiment is completely anonymous. None of your personal information will be taken down and you will only be known as a number.”
(I) The experimental list of words had the name of the colour written in a different coloured ink to what the word said. They were asked to, “name the colour of ink the word is written in.”
(J) The control list of words had the name of the colour written printed in the same coloured ink. They were again asked to, “name the colour of ink the word is written in.”
(K) “None of your information will be used and this experiment is completely anonymous. Do you have any questions or queries?” Any questions or queries were then immediately dealt with by the researchers. They were then asked, “If you feel comfortable to leave, you now may do so, if not, do you have any other queries?”
(M) Stats test.
(N) Each participant had the same list of words, they had the same briefing, instructions they were given were exactly the same, the same room was used, with the same experimenters.
(O) Consent was given, the right to withdraw was emphasized and each participant was debriefed.
(P) Once they had started the stroop test, they wasted time by crying out, “This is really hard!”