Investigation on a variation of the Stroop test

Investigation on a variation of the Stroop test The role of automatic and controlled processing was examined in an experiment looking at the allocation of processing resources between the two. Previous research found that when a word is written in the same ink as the colour the word denotes, it takes longer to state the colour of these words than if the words are colour neutral i.e. not the name of a colour. In the present experiment the type of word used was manipulated, between colour associated and colour neutral words. The results showed that there was a significant difference between the completion times of the two conditions which provided further support for the idea that automatic processes can interfere with controlled ones. Introduction The cognitive process of attention is said by psychologists to be how an individual processes the information that they receive from their day to day environment and how it is selected to be stored. That is to say that not all information that we obtain from daily life is seen as important for storage, it is essentially a selection process in which the most relevant information is chosen to be retained. William James(1890) believed attention to be dependent upon an allocation of cognitive processing resources(James,(1890),p9). The idea that all actions implore the use of processing resources to some extent, and is reliant upon the amount of resources available to an individual is known as a controlled process. Up until more recent years it was believe that no demand was placed upon these resources when the processes were automatic i.e. occurring without conscious awareness. These automatic responses were thought to use up less processing resources due to the lack of conscious effort involved, thus leaving resources free to attend to other stimuli. Thus essentially attentional processing has to be divided between the two. This was termed the two-process theory by Shiffrin and Schneider((1977),p21). Researchers felt that this appeared to be a very useful concept as essentially it would leave more resources free but were interested to see at what cost. J.R. Stroop(1935) was one of these researchers(Stroop(1935),p21). He carried out an experiment into the relationship between automatic and controlled processes. This consisted of two conditions, in one participants were given a set of colour name words written in coloured ink but never matched to the colour ink they were written in. e.g. the word yellow written in blue ink. This is known as the Stroop condition. In the other the participants were given a set of neutral words e.g. the word rat all written in the same colour inks as in the previous condition. The participants were required to name the colour ink in which the words were written as fast as possible. It was found that participants could state the colour of the words in the neutral condition more rapidly than in the Stroop condition, leading Stroop to conclude that peopl e are inclined to read the colour the word is portraying rather than the one it is written in. This is said by Stroop to suggest that the automatic process of reading can hinder the controlled process of naming the ink. It also shows that automatic processes are not necessarily free as researchers once believe and can on fact be influenced by conscious strategies such as naming the colour in which the word is written. Many variations of the Stroop test have been carried out since the original to further test individuals attention and the allocation of resources in both controlled and automatic processing. One such variation is the reverse Stroop test.(Wikipedia) In this experiment there were still two conditions; one where the participant was given a list of colour words and had to point to a block of colour which matched the colour word stated. The second condition was the same as in the original Stroop test where the colour ink the word was written in had to be stated. It was found that it took on average 7 seconds longer to state the colours of the words aloud than it did to simply point to a block of colour that matched it. It was concluded that when the colour of the word stated differed from the colour ink it was written it the automatic process of reading the word again interferes with the controlled process of naming the ink colour. It was also discovered that this can be controlled but th at then a time delay is incurred. This idea that automatic processes do rely on resources just like controlled process, but that they occur without conscious awareness is still open to debate as despite the vast amounts of research done on this topic it still remains to be seen if the Stroop effect only occurs with colour words. The idea that it is not only colour words that cause an integration between automatic and controlled processes is explored in the present experiment, by testing a set of colour- related words against a set of non-colour related words rather than a collection of coloured words printed in either black ink or opposing colours. The hypothesis was that people take longer to state the colour ink in which 30 words are written when the words are colour- associated words rather than colour-neutral words. This is a one-tailed hypothesis. The null hypothesis is that there will be no difference in the time taken to state the words in each condition, and if there is it is due to chance. Methods Design The design of this experiment was within-participants as the same set of participants were used to acquire the data in both conditions. The independent variable was the colour associated words. This consisted of two conditions, a colour associated word condition (condition 1) and a non-colour associated condition (condition 2). In the colour associated condition (condition 1), participants were timed to see how long it took them to state the colour ink of 30 colour associated words when written in opposing colours. E.g. plum written in orange. In the second condition the same procedure was followed but with the participants stating the colour ink of non-colour associated words. E.g. plan written in blue. The dependant variable was the time taken to complete each task, measured with a stopwatch to the nearest second. Several things were done to try and control for any confounding variables. Firstly, all participants were given the same set of instructions in order to prevent them gain ing a different interpretation of what was being expected of them. Another thing that was done was to ensure that none of the participants could confer during the time in which the experiment was taking place, thus helping to prevent them from incurring demand characteristics. Participants also took the two conditions in different orders to help control for practice effects. Finally, all participants were shown the exact same copies of the stimuli which made it easier to ensure that this is not a reason for any differences that may have occurred. Participants Twenty five participants took part in this experiment. 16 of these were recruited by a researcher at the Open University and consisted of their friends and family. The other 9 were recruited through asking friends and family of the researcher. The age of the participants ranged from 17 to 69 and was made up of 12 males and 13 females. Materials A stopwatch accurate to the nearest second was used to time how long it took each participant to state the colour the words were written in. The visual stimuli presented in each condition consisted of 30 words placed into two columns on an A4 piece of paper. For condition 1 these consisted of 6 different words (blood,plum,carrot,sky,grass and lemon) written in 6 different colours (red,orange,blue,green,yellow,and purple). The word was never written in the correct colour i.e. sky would never be blue. In the second condition a different set of 6 words was used (plan,sty,ledge,grade,career and blame). These were written in the same 6 colours as the words in condition 1. In each condition each word was used 5 times and presented in a random order. A set of each stimuli is shown in the appendicies (appendix 1). A set of standardized instructions was also used to explain what was required of each participant (appendix 2). Finally each participant was required to complete a consent form bef ore carrying out the tasks (appendix 3). Procedures Each participant was asked if they would be willing to take part in a psychology experiment looking at cognitive processes, that would take about 5 minutes of their time. The ones who agreed to were given a consent form to fill in stating that they were willing to take part. They were then tested one at a time with their age and gender being recorded before being read the instructions as to how the experiment would work. i.e. that they would be shown a list of words and were required to state the colour the word was written in whilst being timed to state all 30 colours. They were also told that there would be two conditions and that the same procedure was required for each. (instructions appendix 2). Once all of this was understood and the participant had asked anything they wanted to they were given the words for condition 1. The stopwatch was started as they stated the first colour and stopped after they had stated the 30th. This time was recorded in the same table as used to recor d the participants age and gender earlier in the experiment.. The same was then repeated for condition 2 and the time recorded. The order in which the participants carried out the two conditions varied. Once all of this was completed the participant was given a debrief about the nature of the experiment and asked if they wanted to ask anything or needed anything. They were also made aware again of their right to withdraw at any point after the experiment should they decide they are uncomfortable with their data being use, and of the fact that their data would remain anonymous should they allow it to be used. Results The one-tailed research hypothesis was that people take longer to state the colour ink in which 30 words are written, when the words are colour- associated words rather than colour-neutral words. This was measured with a stopwatch accurate to the nearest second (appendix 4 raw data). Table 1-Paired -Samples T-test data Mean N Std. Deviation Std. Error Mean Pair 1 Colour associated words 25.6190 21 4.95456 1.08117 Colour-neutral words 22.9048 21 3.94848 .86163 As can be seen from table 1 above, the mean response time for the two conditions was fairly different with the mean for the colour- associated words being 2.7 seconds slower than the speed for the colour-neutral words. This difference can further be seen from the error bar chart below(graph 1). Graph 1 shows that we can have 95% confidence that the population mean for condition 1 (the colour associated words) will lie within :- 1.08117 x 1.96 = 2.12 Therefore the lower bound is 25.62-2.12= 23.50 seconds Upper bound is 25.62+2.12=27.74 seconds Or 25.6 2Â ± 2.12 seconds Graph 1 also shows that we can have 95% confidence that the population mean for condition 2 (the colour neutral words) will lie within :- .86163 x 1.96 = 1.69 Therefore the lower bound is 22.9 1.69 = 21.21 seconds Upper bound is 22.9 + 1.69 = 24.59 seconds Or 22.9 Â ± 1.69seconds Therefore, although it appears from the experiment that when condition 2 is used the individuals can read the words more quickly, this cannot be confirmed with any confidence. It is possible that in reality that condition 1 could result in those being test reading the words than under condition 2. For example, if the real mean of the whole population is towards the upper bound for condition 2 and towards the lower bound for condition 1, the individuals will be able to complete the test more quickly under condition 1.if there was no overlap between the bounds for each condition it would have been possible to say with 95% confidence that one condition allowed the individuals to complete the test more quickly. A paired t-test was conducted on the data which showed that (t(30)=4.214;p=