The extraneous variables include:
- Order effects eg fatigue – fatigue can play a part in the experiment and can have a direct effect on the number of words recalled by the participant. Therefore, to overcome this problem, there will only be a 2 second gap between each word being read, and the participants will be asked to recall the words as soon as they have heard the list of words. This speeds up the procedure to ensure there is only a short time lapse.
- Demand characteristics – the participants may develop an understanding as to why the experimenter is asking them to carry out the task. Therefore, both the male and female participants will try harder to remember the words due to their competition with the opposite sex. To overcome this extraneous variable, the participants will only be told the aim of the experiment in the debriefing after they have carried out the task.
- Evaluation apprehension – the participants performance may be inhibited by their concern that they are being judged by the experimenter. Therefore, the participants will not be watched whilst they are recalling the words.
- Experimenter bias – this is when the experimenter shows unintentional bias when giving instructions to participants or when recording data from an experiment. To ensure experimenter bias does not play a part in the investigation, a single blind method will be used. This means the participants will be unaware of the nature of the study so they will not be influenced by the experimenter.
- Time of day – this links to fatigue so therefore the experiment will be conducted between 1300h and 1500h when fatigue is usually at its minimum.
- Chemical imbalance (eg drugs and alcohol) – all drugs and alcohol have some effect on the ability to recall the words. Therefore, all participants used will be free of drugs and alcohol.
- Noise – the level of noise may affect the participants recalling abilities. The greater the level of noise, the less words the participants are likely to recall. To overcome this extraneous variable, the experiment will be carried out in an empty room to ensure the level of noise is low.
- Hunger – hunger can also affect the ability to recall words. The hungrier the participant, the fewer words they are likely to recall. Therefore, as stated above, the experiment will be conducted between 1300h and 1500h. This is the period just after lunch so the participants will have eaten.
- Stress – participants used will be stress free whilst participating in the experiment as the greater the level of stress the participant is under, the less words they are likely to recall.
Target population
As this task requires a certain degree of concentration and to ensure all the participants fully understand the instructions given, and that parental consent is not needed (as this slows the investigation down), the target population for this experiment are males and females between the ages of sixteen to eighteen years old. Ten males and ten females will be used for this experiment. The same number of males and females will be used to ensure that it is a fair test and by using twenty participants will give the results more ecological validity than by using only ten participants for example. Also, by using this number of participants will enable an average number of words to be calculated and any anomalous results will be highlighted and accounted for.
As this is an experiment where an independent variable is being manipulated to see what effect it has on the dependant variable rather than a correlation study and due to the target population being used, the most logical sampling method to use is opportunity sampling. This is where the sample is selected on the basis of who is available at the time of testing and who is willing to take part. An advantage of opportunity sampling is that it is quick and convenient for the time allowed for the investigation and it will provide a representative sample of the target population. This in-turn will lead to more reliable results being produced which will allow scope to generalise the findings.
Ethical issues
Before carrying out the experiment, there were a number of ethical issues that needed to be considered. These include:
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Consent – will be required from all participants.
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Right to withdraw at any time during the experiment.
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Deception – the aim of the experiment and the task they have to carry out will be explained to the participants in the briefing.
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Confidentiality – all participants results will be confidential but when published will not be identifiable.
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Briefing – participants will be briefed before the experiment to decide whether they want to participate in the experiment or not. Due to the nature of the experiment, the participants will not be told the aim of the experiment here as this may affect their performance of the task.
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Debriefing – after the experiment, the participants will be told the aim of the experiment and will be informed who will have access to the results and where they will be published. However, all participants will be given a code so the results will remain anonymous. Even at this stage, if the participants have any objections, they have the right to withdraw their results from the experiment. Also, the participants will be fully reassured that it is not their intelligence that is being assessed through this memory test as this may deter them from having their results published.
Finally, in the debriefing, the participants will be thanked for participating in the experiment.
In order to keep these ethical issues under control, all the participants will be asked to fill in a consent form before taking part in the experiment.
See Appendix One for a copy of the consent form.
Task and materials
The participants will carry out the experiment one at a time. The experimenter will read a list of twenty words with a two second gap between each word to the participant who will be asked to memorise as many of the words as possible. After all twenty words have been read, the participants will immediately write down as many of the words as they can remember.
As this experiment is about the verbal memory, the only materials used will be the list of words read by the experimenter, a stop clock to time the 2 second interval between each word, a blank piece of paper and a pen.
A list of 20, three lettered (monosyllabic), concrete words will be randomly chosen using a lottery style sample. They will be concrete, monosyllabic words to ensure that none of the words stand out from the list as this may make them easier to remember and therefore distort the results. Abstract words will not be used as participants may not be familiar with them unlike concrete words which are already stored in the LTM.
The first forty concrete, monosyllabic words from an infant’s storey book will selected and placed into a hat. The first twenty words that are picked out of the hat will be used for the experiment. An infant’s book will be used to pick the words as it will have a high concentration of this type of word because young children will be incapable of understanding complex or longer words.
This lottery style sample of choosing words will ensure that the words used are completely randomly chosen.
See Appendix Two for a copy of the word list.
Procedure
The instructions to the participants were standardised as if participants heard different instructions, it may affect their understanding and performance of the task. This would lead to inaccurate results with low ecological validity. Also, the instructions did not contain any subject specific language as this may confuse and deter the participant from taking part in the experiment.
A candidate who fits in the target population was approached:
Excuse me please, I am carrying out an experiment as part of AS Psychology Coursework and I would be grateful if you would help me by participating in the experiment.
If the candidate agreed to participate in the experiment they were be given a briefing:
Thank you for participating in this experiment. Due to the nature of the investigation, I cannot tell you the aim of the experiment until you have carried out the task. Before participating in this experiment, I would like you to fill out this consent form (give the participant the consent form). Do you still wish to participate?
I would like to assure you that it is not your intelligence that is being assessed by this experiment and you have the right to withdraw from the experiment at any time.
Instructions to participants
I will read a list of twenty, three letter words to you with a 2 second interval between each one. Your task is to remember as many of the words as possible. As soon as you have heard all twenty words, I will ask you to write down as many of the words as you can remember. There will be no time limit for the time allowed to recall the words so there will be no rush. Do you have any questions?
After the participant had performed the task, they were debriefed:
I would like to thank you again for participating in this experiment. The aim of this experiment was to find out whether there is a difference in the verbal memories of males and females.
Your results will only be published in the write up of this experiment and will not be available to any one else other than the examiner. Although the results will be published, you will remain anonymous as I will allocate a code to identify the results; not your name. Finally, you have the right to withdraw your results from the experiment. Do you have any questions?
Results
The male participants can be identified as they have all been given the letter A. the number following the A is the number in which they participated in the experiment. By giving the participants a code enables the results to remain anonymous.
A table to show the number of words recalled by the 10 male participants
Total number of words recalled = 97
Mean number of words recalled = 9.7
Median number of words recalled = 10
Modal number of words recalled = 10
Range = 5
Overall percentage of words recalled = 48.5%
The female participants can be identified as they have been given the letter B. The number following the letter B is the number in which they participated in the experiment.
A table to show number of words recalled by the 10 female participants
Total number of words recalled = 100
Mean number of words recalled = 10
Median number of words recalled = 10
Modal number of words recalled = 10
Range = 7
Overall percentage of words recalled = 50%
See Appendix Three for a copy of the calculations
The following table summarises the number of words recalled by both males and females. This enables the results to be seen clearly and without the need for cross referencing:
Discussion
The results for this experiment show that overall females did recall a higher concentration of words than males. However, the original one tailed experimental hypothesis which stated that females will recall a significantly higher number of words than males has been proven to be incorrect because the difference in the number of words recalled by the two genders was minute. Therefore, the null hypothesis is a correct statement. Females showed a 1.5% better recall of words (ie the females recalled 3 more word than males). Also, notice that the mean number of words recalled by males and females are similar (9.7 words for males and 10.0 words for females). At first glance, this would appear to indicate that the verbal memories of males and females are almost identical.
There could be many reasons as to why there was only a small difference in the number of words recalled. For example, all the words used on the word list were monosyllabic so none of the words stood out from the list. Also, none of the words were gender stereotypic (eg pan for females and car for males) which may have made them more easily remembered by the certain gender. This would have produced inaccurate, unreliable and less ecologically valid results.
This experiment supports and backs up the background information. For example the Maccoby and Jacklin study (1974) also found that females are marginally superior at verbal memory tasks. However, Maccoby and Jacklin made an interesting evaluation which needs to be taken into consideration. They said that the difference in the verbal memories of males and females may be overestimated because the studies that do not find the same results are rarely published.
This experiment also found that the first three words and the last word of the list were very frequently recalled by both males and females. Again, this supports the background theory of the primacy and recency effect. The words at the beginning of the list were remembered as the participant had time to rehearse them so they were stored in the LTM and the word at the end of the list was still stored in the STM.
However, the words ‘bat’ and ‘mat’ from the middle of the word list were also recalled by the majority of both male and female participants. This is because they are rhyming words which followed on from one another so they may have been more easily remembered. This could have affected the reliability of the results. Therefore, it this experiment was to be improved, any rhyming words would be excluded from the list to ensure they are not easily remembered.
Out of all 20 of the participants, only 6 of them managed to recall over 50% of the words (3 males and 3 females). This provides evidence for the dual coding theory supported by Paivio. He proposed that verbal material is held in a verbal store and nonverbal material in an imaginal store. He concluded that images or pictures are likely to spark corresponding words but words do not. Therefore, images are more likely to be remembered as they are kept in both forms of storage.
Although females did marginally out-perform males on this verbal memory task, the difference is too minimal to generalise by saying females have a better verbal memory than males. Both males and females performed similarly because the target population used for the experiment was 16 to 18 years olds and the sampling method used was opportunity sample. This target population was found at a secondary school and all the participants were members of the sixth form so they all had some similar characteristics such as intelligence which can affect recalling ability. Therefore, this experiment did not produce a very representative sample of the target population and has produced results which do not have much ecological validity. Therefore, if this experiment was to be re-conducted where time was not a limitation, a larger sample of participants (for example 100 males and 100 females) from a larger target population would be used to ensure that all of the participants have varying degrees of intelligence and contrasting personalities and general characteristics. The sample of participants from the target population would be chosen using a random sample. Each member of the target population would be given a number then a computer which generates random numbers will be used to choose the sample. This would produce an unbiased, representative sample of the target population which in turn would produce results with more ecological validity.
Also, it was impossible to control some of the extraneous variables such as stress levels and intoxication of participants. The higher the levels of stress and intoxication, the fewer words the participant is likely to remember. Again, this may have affected the accuracy and reliability of the results.
Another aspect that could have distorted the results was that some of the male participants were also psychology students. Therefore, they already had an in-depth knowledge of memory and how to maximise their memory so they may have put these memory techniques into practise whereas no on else could have. Other psychology students would not be used as participants if the experiment is carried out again.
A follow up investigation to this experiment would be to investigate the recall of images instead of words and then to compare and contrast the results with the results of this investigation. For example, 20 images would be shown to the participants for 3 seconds with a 5 second interval between each image. After all the images have been shown, the participant would recall as many images as possible.
Conclusion
The aim of this experiment has been achieved as it has been found out that the females who took part in this verbal memory test only very slightly out performed the males who took part in the test. Therefore, the experimental hypothesis has been proven to be incorrect but the null hypothesis is correct as there was no significant difference between the verbal memories of males and females.