The Stroop Effect Essay Example

ability to divide ones attention between two or more tasks.

If one of these tasks becomes an automatic process it becomes easier to divide ones attention between these two tasks. However, sometimes rather than being helpful, interference can occur between the controlled process and the automatic process (Tzelgov, 1999). Psychologists have frequently found that the powerfully autonomic nature of reading words or in this case numbers, as it is such a well-learned automatic activity can interfere with other tasks.This idea has been researched by a number of researchers. Kahneman (1973) devised a model of divided attention, which was based around the idea of mental effort.

He proposed that some tasks might be relatively autonomic, so make fewer demands in terms of mental effort, such as a reading task. Several activities can be carried out at the same time, provided that their total effort does not exceed the available capacity. So usually an autonomic task will not require much mental effort and so often can be carried out automatically. Kahneman, 1973) In an experiment done by Stroop (1935), he carried out an investigation into autonomic processing, by inventing the stroop effect.

In this, he instructed participants to read a list of color words written in black ink. This, evidently a very simple task was easy for the participants to carry out. Following this, participants were asked to read a list of color words written in conflicting colored inks, for example, the word “red” written in blue color ink and to call out the color ink the words were written in.Although this task seems very simple at first and is only matter of simple color recognition, Stroop

found that it took the participants considerably longer to complete this task then the previous. This is because, the powerful autonomic or the unconscious nature of reading words meant that participants automatically wanted to read the words rather than the color ink they were written in. So, even though the participants did not often read the color word out loud, there was a time delay while the participants thought of the correct response which was the color ink (Stroop, 1935).

This Stroop effect can also be found when the participants are not consciously aware of the colour name being presented (Cheesman and Merikle, 1984), which indicates that the word identification is an automatic process, not available to consciousness and therefore not under our control. Some research, though, seems to suggest that the processes behind word identification are not entirely automatic, they are to some extent avoidable.A study carried out by Kahneman and Henik (1979) supported this as they found that interference was greatly decreased when the colour name is in an adjacent location, rather than in the same location as the colour which participants are asked to name. Again though, this reduction in interference is due to the placement of the distracting word, not due to any effort by or ability of the participants.

However, evidence from a recent series of experiments conducted by MacLeod and Dunbar (1988) suggests that the processes involved in the Stroop task may have not been inadequate.In their experiment they taught participants to use color words as names for arbitrary shapes that actually appeared in a neutral color. After 288 trials where there was a 72 trials per stimulus, participants could

perform this shape-naming task without difficulty. At this point, the effect that ink color had on shape naming was tested by presenting participants with conflicting and congruent stimuli for example, shapes colored to conflict or agree with their assigned names. Ink color produced large interference and facilitation effects.However, when the task was reversed, and subjects were asked to state the color of the ink in which the shapes appeared which is known as the color-naming task, congruity of the shape name had no effect.

They also noted that reaction times for the shape-naming task which was a control condition were slower than were those for the standard color-naming task which was also a control condition. MacLeod and Dunbar's (1988) results are incompatible with the explanation of the Stroop task in terms of controlled versus automatic processing. MacLeod & Dunbar, 1988) In the meanwhile, Shiffrin and Schneider (1977) looked into automatic processing in a lot of detail and identified some of its features in comparison with controlled processes. The typical piece of research carried out consisted of participants being required to search for specific letters which were target items amongst an array of digits which were distracter items. For instance, participants were asked to spot as quickly as possible letters from B-L (target items) within the part of the alphabet from Q-L (distracter items).After 2001 trials, the participants were able to spot the target items extremely quickly without having to think about the alphabet each time.

Now in the second part of the experiment, the target items and distracter items were swapped around which meant that the previously learnt task of spotting letters from B-L changed

into having to spot letters from Q-L. Shiffrin and Schneider found that the time taken for them to carry out this task significantly increased.This is because the already learned, automatic process was very difficult to change, which shows how automatic processes are fixed and rigid and after practice it can become automatic (Shiffrin & Schneiders, 1977). Shiffrin and Schneiders research was based on visual rather than auditory tasks, so Poltrock et al.

(1982) came out with an experiment which carried out an auditory detection task. In this experiment, participants listened for one or three target letters embedded in a stream of dichotic letter pairs.Subjects responded faster and made fewer errors under the consistent mapping (CM) condition than under the varied mapping (VM) condition and the effect of memory set size decreased over practice in the CM condition but not the VM condition. The results are discussed in terms of automatic and controlled processes involved in recognition of target stimuli. A review of research on auditory target detection suggests that the development of automatic processes may account for some apparent incongruity in the text (Poltrock et al, 1982).

This experiment showed that it has the same results as Shiffrin and Schneiders research. The present study aims to carry out a modification on the experiment on automatic processes carried out by Stroop and to discover whether the results correspond. The experiment was conducted with a numerical stroop effect to find out whether reading numbers had the same effect on automatic processes as it had on reading words. The question here is whether the results will be replicated here.The hypothesis for this experiment is a directional hypothesis which states

that the length of time taken for participants to say out the number of number in the incongruent part will be longer than for participants to say out the number of numbers in the congruent part. Method Participants A number of hundred and eighty participants were recruited for this study.

The participants consist of 77 males and 89 female. There were 14 data missing in the experiment. The participants whom took part aged between 18 to 89 years.No participants who were approached refused to take part. Materials One task sheet was used, which consist of three parts.

The first part in the sheet was a list of stars. The second part of the sheet consists of a list of number and the final part of the sheet also consists of a list of number. Participants were to read out how many numbers of stars and number there were in each part respectively. A digital stopwatch was used to take note of the time for the participant took for each part (see Appendix A for a sample of the task sheet). ProcedureAt the beginning of the experiment, participants were acknowledged for their effort and time to participate in this experiment.

The participants were then informed that they may withdraw from the experiment at any time if they experience any form of discomfort. Next, the experimenter read out the instructions for the participants to follow. The participants were shown the first part in the task sheet which consist of some stars. The participants were required to say out the number of stars to the experimenter by reading each row downwards starting from the leftmost column as quickly

and accurately as they can.Participants will then be time for the task.

In part 2 of the sheet, participants were asked to say out the number of the numbers in the sheet to the experimenter as quickly and accurately as they can. Participant will be timed for the task. In part 3 of the task participants were again asked to say out the number of the numbers in the sheet to the experimenter as quickly and accurately as they can. Again the participant will be timed for the task (see appendix A for a sample of the task sheet). ResultsThe mean results shows that participant took more time when they were asked to say out the number of numbers which were different or the incongruent condition, for an example, 3333, 44444,555. While, participant took a lesser time to complete the task when they were asked to say out number of numbers which were same or in the congruent condition, for example, 22, 333, 444, 55555.

While, the neutral conditions was when the participants were shown stars and were asked to say out the number of the stars, it was found that participants completed the task in-betweens the time of the congruent and incongruent conditions.The mean scores of the time taken to complete the task in the three conditions is shown below in Table 1. Table 1 Mean of time taken to complete task in 3 conditions Conditions Control Congruent Incongruent Time taken to complete task(s) As shown in Table 1, the mean time for incongruent condition is 17. 48s which is extremely longer than the mean time of the congruent condition which is 10.

87s.

This shows that participant took a longer time in completing their task in incongruent condition than in congruent condition. The control condition has a mean time of 15. 9s which was in between the congruent and incongruent condition. This shows that the congruent condition requires the least time for the participants to complete the task, followed by the control condition and the longest mean time was taken by the incongruent condition. Discussion The aim of this research was to replicate the original experiment with a numerical stroop task and to gain the same results.

The aim was achieved, as the results gained supported the hypothesis that it would take considerably longer time for participants to say the number of numbers which are incongruent than those of the congruent part.This shows that though the experiment was a numerical stroop effect, it showed a similar result with the past researches where there was interference between the autonomic nature of reading words and the color, as first suggested by Stroop( 1935). In stroop’s experiment It also supported Shiffrin and Schneider (1977) and Poltrock (1982) findings that incongruent condition took more longer time to complete than congruent codition. This can be explained with Kahneman (1973) where he proposed that some tasks might be relatively autonomic, so make fewer demands in terms of mental effort, such as a reading task.Several activities can be carried out at the same time, provided that their total effort does not exceed the available capacity.

So usually an autonomic task will not require much mental effort and so often can be carried out automatically. Hence, in this experiment participants took a longer time in saying

out number of numbers in incongruent part compared to the congruent part because autonomic nature of reading words is as same as reading numbers, as it is such a well-learned automatic activity it does interfere ith other tasks. However, the results obtained was not corresponding with MacLeod and Dunbar (1988), where the results obtain from the experiment done by them contradicted with this experiments result. MacLeod and Dunbar (1988), stated that in their experiment they taught participants to use color words as names for arbitrary shapes that actually appeared in a neutral color. After 288 trials where there was a 72 trials per stimulus, participants could perform this shape-naming task without difficulty.Hence they concluded that the results obtained by them are incompatible with the explanation of the Stroop task in terms of controlled versus automatic processing.

Though the results of the experiment supported the hypothesis, there are several experimental weaknesses that we must consider in evaluating this study. There are a few methodological limitations which could have affected the results of this experiment. One of the weaknesses which could have affected this experiment is because of biased sample.The sample only consisted of a particular age range which means that the results are only valid for this population and are not generalisable to the whole population. Another weakness of this experiment is the timing. This could have occurred when the experimenter could never be fully accurate with the timing, as using a stopwatch is bound to cause human error.

If the experiment is going to be carried out in the future, perhaps the stroop effect test could be done on a computer screen with the numbers

flashing on a screen before the participant’s eyes and once completed, the computer itself can stop the timer.Other weakness of this experiment is that the experiment itself was very artificial as it was carried out in an artificial environment. People would not usually find themselves in situations where they have to read a list of numbers from a sheet of paper in the real life. Therefore, the experiment lacks of ecological validity and the findings could not be applied to real life situations. As a conclusion the results obtained in this experiment tested the hypothesis. However, there were certain limitations in this experiment which may have come into play.

Hence, future research needs to be done to clarify the results. Further research could of course look into any differences in the task between age groups or gender References Cheesman, J. and Merikle, P. M. (1984). Priming with and without awareness.

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Tzelgov, J. (1999). Automaticity and Processing Without Awareness. Retrieved March 1, 2008 from the World Wide Web: http://psyche. cs. monash.

edu. au/v5/psyche-5-05-tzelgov. html Appendix A Sample of a task sheet used in the experiment. ** ** **** ***** **** ** ** ****** *** **** *** ****** ****** ****** ***** *** **** ** ***** ** **** **** ***** *** 66666 333 4444 4444 666666 55555 333 4444 22 22 55555 333 4444 22 666666 666666 666666 4444 55555 333 55555 333 666 444 444444 333336666 555 222222 333333 66666 5555 55 222 44 22222 44444 66666 3333 5555 222 66666