Clive Wearing and H.M
A: To test whether the STM functions separately to the LTM, as Clive's STM functioned, but he had a severely impaired LTM.
P: A longitudinal study has been used to research in to these as it shows how they have not changed over these years. The participants were observed in their natural settings - their homes. The researchers watched how they interacted with family members and doctors throughtout he day.
F: By observing them, researchers could witness how they were not able to form any new memories as they could only remember up to 30 seconds ago. In the case of H.M, researchers noted how he culd remember everything up until he was 16. Researchers determined that the STM and the LTM were seperate because they could remember things from years ago, but couldn't form new memories because they could only remember information for about 10 seconds.
Co: This supports the theory of the WMM because it indicated how one type of memory could function without the other. It also showed that it was a journey, as the info had to go from the STM to the LTM, meaning they could rember anything new.
Cr: This study is hard to generalise because these cases are extremely rare.
Serial Positon Effect
A: To test whether the postiton of words in a list has an impact on memory and recall.
P: Participants took part in a laboratory experiment where they were presented with a list of words they had to recall in any order.
F: Words at the beginning and the end of the list of words were recalled better than the words in the middle. This is the serial postiton effect. Words at the beginning of the list are recalled because they have been constantly rehearsed and transferred to the LTM, while words from the end of the list are recalled as they are still in STM.
Co: This supports the idea of seperate STM and LTM - therefore supporting the WMM. It shows that it is a system, as the words were transferred from the STM to the LTM systematically through attention or repetition.
Cr: This study could be limited due to participant variables. For example, if a participant was dyslexic or didn't speak English very well, they may struggle to recall any words, irrelevant to their position.
Peterson and Peterson (1959)
A: To test the duration of how long information can be stored in the STM without recalling it.
P: In a laboratory experiment, they read nonsense trigrams (such as XQF) to participants and then got them to count backwards in threes from a large three-digit number for between 3 and 18 seconds.
F: About 90 per cent of trigrams were recalled with a 3 second retention interval, but only around 5 per cent after 18 seconds.
Co: This shows that the duration of the Short Term Memory is approximately 20 to 30 seconds.
Cr: This study could be limited due to participiant variables. For example, if a participant was dyslexic or had English as an additional language, they may struggle to remember letters, unrelated to the time preventing them from repeating it. Also, recalling nonsense trigrams bears little relevance to STM tasks occuring in our everyday lives, so therefore lacks realism.
Baddeley et al (1975)
Word Length Effect
A: To test whether the length of a word affected the amount recalled
P: In a laboratory experiment, participants were shown lists of words that they had to remember, and then recall. The words varied in length and were chunked in varing sizes.
F: They found that the length of words being chunked affected recall. Particpiants were more able to recall short words than long ones.
Co: This showed that the capacity of the STM was small and limited, to about 7 +/1 2 pieces of information. This research condradicted the one-way system of the WMM because, through the process of chunking (combining items in to meaningful units), particpants were using information alreaady in the LTM to assist in the memory of something in the STM.
Cr: This study is limited due to participant variable, because if they were dyslexic or only spoke English as a second language, they could struggle to recall words anyway.
Dual Task Experiment
A: To test investigate the existence of a visuo-spatial sketchpad in STM.
P: Particapnts were asked to complete a visual tracking task at the same time as describing angles on a letter or carrying out a verbal task.
F: Particpants found it really hard to complete the visual tracking task at the same time as describing angles on a letter because they both used the visuo-spatial sketchpad component at the same time, so they couldn't concentrate enough on one. However, during task 2 (completing a visual tracking task at the same time as carrying out a verbal task) participants perfomed much better because this uses different components, the visuo-spatial sketchpad and the phonlogical loop, so they are individually focused wholely on each one.
Co: This supports the existence of seperate stores in STM because the findings show that the visual and auditory information is inputed seperately because participants could focus on each task with a seperate component better when it was a different section and they struggled to concentrate on two things from a the same section.
Cr: This study is not very limited.