The results show that more trigrams were recalled from participants who had no interference to contend with. This can be shown most clearly by the mean (7.8) and mode (9,7,6) which have considerably higher numbers than the mean (4.2) and mode (4) of participants who had interference. Another good indicator of the difference between results is the highest value. This value is five higher (11) in the no interference group compared to with interference (6). The lowest value is three higher (5) compared to 2. Apart from that ‘5’ value in the no interference group, there does not appear to be any anomalies.
The bar chart, however, is the clearest portrayal of the results. The chart compares the two mean values of the groups and because one (7.8) is 3.6 values higher than the groups with interference (4.2), this is very obvious on the chart. The value 7.8 is just over half of the maximum number of trigrams that could be recalled; 4.2 is just over a quarter of the maximum number of trigrams that could be recalled.
The results produced certainly support my experimental hypothesis in that those boys without rehearsal time recalled fewer letters from memory – they managed only 4.2 words on average compared to 7.8 by boys with rehearsal time. The reason for this was because they had to count backwards in groups of threes and therefore their rehearsal time was blocked. These results however do not support those achieved by Brown (1958) and Peterson and Peterson (1959) who concluded that information remained in the STM (without rehearsal) for only 18 seconds. The results quite clearly show that even without rehearsal, participants were able to recall some words after 20 seconds.
Implications of Study
The results that I have achieved from this study are useful when discussing the background theories related to it. Not only did the results support my experimental hypothesis but they also helped support the Atkinson and Shiffrin multi store model of memory. The model argued the existence of a rehearsal loop between the STM and LTM and the study I carried out certainly supported this. Those participants who actually rehearsed the trigrams managed to recall a significantly higher amount of them.
Another implication of the study is that, although the experiment did not support the Brown and Peterson technique (they claimed that information stayed in the STM for a maximum of 18 seconds; my results, however, show that after 20 seconds the participants still remembered some words), the results of the group without interference produced results that supported Miller’s (1956) experiment. He claimed that the number of items that could be held in the STM is seven, with an allowance of two on both sides, i.e. 5 and 9. This supports my mean result which is 7.8 and therefore surprisingly precise.
The study was carried out in a small area over a short space of time and to a small and limited sample of people. This means a generalisation outside the target population is virtually impossible. However, even though the sampling used was opportunity and therefore biased, a generalisation to the target population would not be impossible. One would believe that many 16-18 year old public school boys with a higher than average IQ would achieve a very similar set of results. Students from different countries also took part in the study so to an extent the results can be generalised to varying cultures and races
The form of interference in the experiment was counting backwards in threes from 681. However, if the interference had been that of music or television one could question whether the generalisability of the study could have been extended outside the target population as this form of interference is much more common than the one used in the experiment.
In the end, the study was a good measure of the Atkinson and Shiffrin multi-store model of memory as it certainly tested the existence of a rehearsal loop. However, there are problems with the validity of this experiment. The experiment is a field experiment and is therefore more realistic than a laboratory testing, but the task that had to be done and, to some extent, the setting are artificial. Learning trigrams in a school common room is simply not an every-day activity that one performs.
It can be argued whether the experiment has ecological validity, as although the school common room may be a natural setting regarding a pupil’s school life, it is not natural regarding his life on a wider scale.
Possible improvements in the validity could be made. Certainly the task could be changed to a more appropriate and realistic activity. Considering that the experiment is performed on 16-18 year olds, perhaps the learning of an educationally related subject could be incorporated. This might be foreign vocabulary or symbols related to passing a driving test. Another way the experiment could be made more realistic is by changing the form of interference. It is safe to say that most 16-18 year olds do not have their learning interfered with at home by having to count backwards in threes from 681 – it is simply not natural. Therefore a change in intervention would be useful. Possibilities are using music or the television to cause distraction, mediums that a teenager is much more likely to be used to and are more common. This is therefore a more realistic way of testing how distracted the pupil becomes.
Taking into account the ecological validity, I think I would have to extend the range of sampling to any age. This would mean I could perform the experiment with the general public, in public areas. This would, however, cause a problem with the reliability of the experiment. Ethically, the study is fine as the participant in each case gave his consent. If informed was given, the participant would have known too much.
As validity and reliability affect each other, the lack of validity in this experiment causes it to be very reliable. The study is extremely tightly controlled with the participants given the same amount of time to learn the trigrams in the same place. The list of trigrams is kept the same and the participants are chosen carefully – all are 16-18 years old and male public school boys – the fact that I used opportunity sampling made it quicker and fairly ethical but on the other hand it is biased as I was choosing who was available. To an extent I could reduce the background noise by sending the participant to a quiet area of the common room. However, the amount of background noise at any time could not be controlled. Neither could the mood of the participant, as some were happy to perform the experiment whereas others were not and they found it tedious – this could have affected the results. I was able, though, to make sure the participant had no previous exposure to the experiment because I used independent groups instead of repeated measures. Generally though, the fact that my procedure is so clearly stated makes the study easy to replicate.
Improving the reliability comes down to the setting of the experiment, which is not accessible to the general public. It would be useful therefore to have performed the experiment in a quite place other than that in a common room, as this would not be available to most people.
Application of the study to everyday life , Certainly the experiment itself is totally unrealistic and therefore can’t be applied to everyday life. However, the concept of testing the rehearsal loop can be applied. This is the basic reason behind every exam – to discover how well the candidate has been able to transfer information between the memory stores. Problems with the rehearsal loop could result in a lack of information being transferred to LTM and therefore poor revision techniques and poor results.
The use of different forms of interference would have been interesting as well. The use of television and music as ways of distraction would have shown to what extent people are affected by everyday forms communication and entertainment. This could be linked to people who drive with very loud music playing and are therefore often the cause of many road crashes through their negligence of those around them.
Brain, C. (2000) AS – Psychology – Approaches and Methods. Published by Nelson