A03 - Memory - Coding, Capacity And Duration Flashcards
A limitation of Miller’s research into capacity is that he may have overestimated the capacity of the STM.
Cowan (2001) reviewed research and concluded that the capacity of STM is closer to 4 chunks of information.
This is closer to the lower end of Miller’s estimate of 5 and suggests that it may be a more appropriate ‘Magic Number’ than 7.
However, as memory can be affected by individual differences, it may be that it is difficult to draw universal conclusions in this area of research.
A limitation of Miller’s research into capacity is that he did not specify the size of the chunk.
Simon (1974) found that people have a smaller STM capacity with larger chunks such as 8-word phrases compared to one syllable words.
This shows that Miller’s explanation is not a complete explanation for the capacity of STM.
However, despite this this research does support the view that STM does have a limited capacity.
A limitation into the research into capacity of STM is that capacity is not the same for everyone as there are individual differences which affect the results.
Jacobs found that digit span recall increased steadily with age. 8-year-olds remembered an average of 6.6 digits and 19-year-olds remember 8.6 digits on average.
This shows that with age perhaps brain capacity increases or that people develop better strategies to improve their digit span.
Therefore, the research into capacity should only be generalised with caution as individual differences appear to affect the capacity of STM.
A limitation of research into capacity is that the findings lack ecological validity as the research is often carried out in an artificial setting.
Jacob and Miller used meaningless words, numbers and objects to test participants recall which is not reflective of how memory is used in the real world.
In real life memory often has much more personal significance such as remembering people’s birthdays and remembering daily activities.
Therefore, as the tasks lacked mundane realism and the results from these lab experiments may only be generalised to the real world with caution.
A limitation of P&P is that it may not have been measuring trace decay but in fact displacement, lowering the construct validity of the research.
The participants were asked to count backwards in 3s or 4s as a distraction task. This complicated task may have overwritten the trigrams and instead created displacement, rather than merely preventing rehearsal.
When Reitman (1974) used auditory tones instead of numbers he found that the duration of the STM was longer.
This suggesting that the validity of the results from P&P were low due to their methodological limitations.
A limitation of P&P is that the results of the study lack ecological validity.
The stimulus material in the task was very artificial and therefore lacked mundane realism e.g. participants had to memorise trigrams which is not reflective of real-life examples of memory.
Whereas in real life settings people must remember things like birthdays and events.
These have more personal significance than nonsense syllables.
However, sometimes in everyday settings we do have to remember meaningless things like phone numbers or post codes.
In these instances, the trigram task may be very representative of real life.
Overall, we should be cautious when generalising the findings of this study, as the results have only limited application to specific real-life tasks.
A strength of Bahrick’s results is that they have higher ecological validity than P&P’s research into duration.
This is because participants memory was being tested on their own high school classmates which means that task had higher mundane realism and the results can be generalised to other settings.
However, the issue with this is that there were more confounding variables. For example, some participants may have frequently looked at their year books and others did not, meaning the internal validity of the results are compromised as the researchers may not be accurately measuring the impact of time on LTM recall.
It can therefore be argued that Bahrick’s research has high ecological validity but low internal validity which should be taken into consideration when generalising the findings.
A limitation of Baddeley’s findings into encoding of STM is that there is contradictory research evidence.
Brandimote et al (1992) found that participants used visual coding in STM if they were given a visual task and prevented from doing any verbal rehearsal before the visual recall.
Neslon and Rothbart (1972) also found evidence of acoustic coding in LTM.
This shows that encoding is not always acoustic in the STM and not always semantic in LTM.
Therefore, Baddeley’s findings cannot be generalised to all types of learning equally.
A limitation of Baddeley’s research is that the findings lack ecological validity the research was carried out in a lab setting and the findings must be generalised with caution to the real world.
Baddeley used meaningless words to test participants recall which is not reflective of how memory is used in the real world.
In real life, memory often has much more personal significance such as remembering people’s birthdays and remembering daily activities.
Therefore, as the task Baddeley used lacked mundane realism the results may not reflect how memory is used in the real world.
A strength of Baddeley’s findings into coding showed that there are distinct and separate memory stores.
This is because it showed that STM are coded acoustically and LTM semantically.
This was an important finding which led to the development of the multi-store model of
memory.
The finding of the MSM has a reliable finding which has stood the test of time.
