The aim of the study I am conducting, is to investigate the effect of a distractor task from the recall of a list of words on the STM, of a selection of students
Experimental hypothesis
There will be a higher percentage of accurately recalled words at the end of the list by participants from the condition with a distracter task, i.e. reciting alphabet backwards, than from the condition when no distracter task is used. From Glanver and Cuntiz’s study, it gives me an idea of what direction my results will go; therefore it is a one-tailed hypothesis.
The null Hypothesis
There is no significant difference in the percentage of accurately recalled words from the end of the list, between the participants that were given a distracter task and participants that weren’t.
Method
Design
In this study, participants were given a list of words and asked to free recall immediately after, as many words accurately from the list as possible. Participants were also given a distracter task, and were asked to free recall as many words as possible after the distracter task. The experimental design used was the repeated measures design. This was used because it would eliminate participant variables as the same participants were used for each condition, also only a few participants were required.
The variables in my investigation:
Independent variable(IV): whether or not participants were given a distracter task or not. In this case the distracter task was for the participants to recite the alphabet backwards.
Dependent variable (DV) : the percentage of accurately recalled words from the last seven words of the list, showing the recency effect.
The conditions used in the investigation:
Condition A: Without distracter task, Participants had to immediately free recall as many words from the list as possible once whistle had blown.
Condition B: With distracter task, whistle was blown then participant had to recite alphabet backwards for 30 seconds. Then whistle was blown again and participant stopped reciting alphabet, and had to free recall as many words from the list as possible. 10 participants were used for the study. As repeated measures design was used for study, 5 participants did condition A then B, and 5 participants did condition B then A In order to be sure that any changes I observed in the dependent variable (DV) were actually caused by the changes in the independent variable (IV), I had to control all extraneous variables. An extraneous variable in this study was an order effect. This is when participant’s performance in one condition may affect performance in another condition. Participants may do better in the second condition because they have had more practise. To control this extraneous variable I will use counterbalancing. This means the group of participants would be divided into two. Half of them would do condition A first followed by condition B and half do condition B first followed by condition A. The order of these conditions was allocated to participants by stratified sampling. The list of participants for the sample of this study, was put into alphabetical order and every second person on that list did Condition A first followed by condition B and the remaining sample did condition B first followed by condition A. The same word lists were used for each condition. The environment was controlled by using the same room for each condition , for every participant. Words which were similar to the environment in which the participant, e.g. table, was not used. Words which were significant to the participant, or just everyday words such as cat dog etc., were not used, as they may have effected the results. A stopwatch was used to ensure both groups had the same amount of time to carry out each task. The same brief and the same set of standardised instructions were given to each participant, see appendix 2 and 3, so that all participants were given the same amount of information.
The ethical issues I considered in my study were:
- Withdrawal from the investigation. This was controlled as each participant was given a set of standardised instructions and was told that they could withdraw at any point during the study.
- Protection of participants. This was controlled as each participant was asked to take part in the study and was assured no harm or stress would be bought upon them during the study.
- Consent. This was controlled because participants were under the age of 16, so consent from guardians as well as participants were recorded through consent forms. See Appendix 8 for copy of consent form.
- Confidentiality. To control this, participants were assured that results would be kept confidential.
- Each participant was debriefed at the end of the investigation to make sure they were not misled in any way. See Appendix 4
Participants
10 participants were used for this study. Target population used were year 10 students, at a grammar school in Birmingham. Age range of participants from 14-15 years. Year 10 students were used, so participants in study were naïve as older students may have already taken part in the study, which may affect the results. As this grammar school was a single sex school, all participants were female. Participant sample was produced by random sampling, a list of all students year 10 students, were given a number and by computer, the computer generated random numbers which determined what students would be used for the sample. Random sampling was used because it gives every person in the target population an equal chance of being chosen, so selection is independent from human judgement, which gives an unbiased sample.
Materials
Random word list chosen from magazine, every 5th word was used. See appendix 1. For copy of magazine article, see Appendix 7.
Stopwatch
Results sheet and pen
Set of standardised instructions, see appendix 3.
Debrief and Brief , see appendix 3 and 4
Whistle
Procedure
People were approached that had been selected by sample and the brief was read to them (see appendix 2 ) asked if they would take part in the study. There 10 participants, individually each participant was taken to the room where the experiment would take place, a standardised set of instructions were read to the participant, see appendix 3. According to what condition the participant was doing first,(condition A then B/condition B then A) everything was done the same for each participant.
Condition A : Once list of words has been read out to participant, whistle is blown and participants recall as many words as possible.
Condition B: List of words read to participants, whistle blown then participants recite alphabet for 30 seconds. After 30 seconds, I blow whistle again, and they start to recall as many words as possible.
Researcher on tick sheet recorded results as participant recalled the words. Once investigation over, debrief read to participants, see appendix 4, and any questions answered if asked by participants.
Results
See appendix 5 For raw data see appendix, This shows the number of accurately recalled words for the last 7 words of the list for condition A and B. Mean, mode, standard deviation and range has been calculated for both conditions and put into table below.
Table to show central tendency and dispersion for condition A and B.
Without a distracter task, participants remembered 0.8 more words on average, as you can tell from the mean, than with a distracter task. These results support the experimental hypothesis. The medians are similar to the means, so this can show that the participants are from normally distributed population. The range for condition A and B are equal, therefore the words accurately recalled are about the same so memory of participant in both conditions were similar, Standard deviation are both small, nearly close to 1, therefore shows how closely it is distributed about the mean, so again memories of participants were similar in condition A and B, but higher in A because no distracter task, so rehearsal of words was present in short term memory (STM).
Discussion
The results from this investigation show that there was a higher number of accurately recalled words from condition A (without distracter task), than from condition B. This can be shown from the graph in appendix 6. The graph shows the percentage of accurately recalled words for each position of the last seven words in the list. Condition A curve is much higher, this shows that the 30 second distracter task causes the recency effect to disappear. This supports Glanver and Cunitz study. These results support my prediction of the experimental hypothesis, however reject the null hypothesis. This is because the STM has a duration of about 15-30 seconds, So when participants have no distracter task, the participants tend to recall the last few words of the list ( recency effect). This is presumed to be because the last few words are still in the STM, so within 30 seconds of the end of the presentation they can immediately recall information from the end of the list. However when a distracter task is used it prevents rehearsal of information during the delay between presentation and recall, which causes rapid decay and loss of information from STM. This also supports Atkinson and Shiffrin’s multistore model of memory, as rehearsal acts as a buffer between sensory memory and long-term memory by maintaining incoming information within STM. I conclude that a distracter task affects the recall of a list of words on the STM. It is easier to recall when a distracter task is not present because rehearsal is not prevented.
The main criticism about the study is that it lacks ecological validity. The experiment was carried out in a psychology classroom, unlike a real life experience. One can almost say, to what extent can we generalise these results to everyday memory, as when was the last time you had to remember a list of words. Another criticism maybe that my sample is not representative of 16-18 year olds, as the sample I used were all girls.
To improve my investigation I could use a matched pairs design. Two different groups of individuals are used. However, they have been closely matched, or paired, so that the two groups are almost identical. This design itself controls for participant variables, which may otherwise confound the results of the study.
For a future study different durations of distracter task can be used to see how this affects the recall on STM. Or length of words and syllables can be changed to find out how many chunks the STM can hold, and what effect it has on LTM.
References
Glanver, M. & Cunitz, A.R. (1966) “Two storage mechanisms in free recall,” in Gross (2001) Psychology The science of mind and behaviour, Hodder and Stoughton (a).
Atkinson, R.C. & Shiffrin R.M. (1968) Human memory: a proposed system and its control processes. In Gross (2001) Psychology The science of mind and behaviour, Hodder and Stoughton (a).
Appendix
From the article in Appendix 8 these words were wrote down backwards so the list is not in a specific order like the article.
Appendix 1
Gorgeous
But
All
Home
Be
Bag
Designer
The
Gucci
Of
Fashion
At
Your
Make-up
Flatties
Mini
T-shirt
Wear
Relish
Cool
You
Appendix 2- Brief
Hello my name is Jasleen Chaggar, I am conducting a Psychology experiment. It is a simple word test , where I will present you with a list of words. You have the right to withdraw at any point in the experiment. There will be no harm or stress bought to you by this investigation, I will make sure of that. Your results will be kept strictly confidential. If you are willing to participate can you please follow me to the psychology classroom.
Appendix 3-Standardised Instructions
Condition A:
“ I am going to read out a list of words to you, when I have finished reading I will blow the whistle then can u recall as many words as you can remember from the list.”
List of words was read, the whistle was blown and the results were recorded as the participant recalled.
Condition B:
“I am now going to read out a list of words, this time, when I blow the whistle can you recite the alphabet backwards. When I blow the whistle the second time again can u recall as many words as possible as you can remember from the list.
The list of words were read, the whistle blown and the stopwatch was started for 30 seconds. The whistle was blown again and the results were recorded.
Depending on what order the participants are doing the conditions the instructions are read out according to that.
Appendix 4- debrief
You have just taken part in a memory test,. I was testing to see what 2 conditions would have on the effect of your recall from your short term memory. Condition A was when u were told to recall immediately, condition b was when u had to recite the alphabet. You are able to withdraw your results if u feel u need to.
Appendix 5
Condition A- without distracter task
Participant 1- 2 words accurately recalled
Participant 2- 3 words accurately recalled
Participant 3- 4 words accurately recalled
Participant 4- 5 words accurately recalled
Participant 5- 2 words accurately recalled
Participant 6- 3 words accurately recalled
Participant 7- 2 words accurately recalled
Participant 8- 3 words accurately recalled
Participant 9- 4 words accurately recalled
Participant 10- 2 words accurately recalled
Condition B- with distracter task
Participant 1- 2 words accurately recalled
Participant 2- 3 words accurately recalled
Participant 3- 2 words accurately recalled
Participant 4- 4 words accurately recalled
Participant 5- 1 words accurately recalled
Participant 6- 3 words accurately recalled
Participant 7- 1 words accurately recalled
Participant 8- 2 words accurately recalled
Participant 9- 3 words accurately recalled
Participant 10- 1 words accurately recalled
To investigate the effect of different conditions on the recall of STM.
