Memory: Coding, capacity, and duration (AO3) Flashcards
(9 cards)
LIMITATION: Miller may have overestimated capacity
A limitation of Miller’s research on short-term memory (STM) capacity is that he may have overestimated its true capacity. Cowan (2001) reviewed multiple studies and concluded that STM capacity is closer to 4 chunks rather than Miller’s estimate of 7, suggesting that the “magic number” of STM capacity may be lower than previously thought. This finding implies that Miller’s estimate might be inflated, as his methodology may not have accounted for individual differences in cognitive processing, leading to variability in STM capacity. Consequently, Cowan’s research calls into question the universality of Miller’s “magic number”, suggesting that memory research must consider individual differences to achieve more accurate and generalisable conclusions.
LIMITATION: Miller did not specify the size of the chunk
A limitation of Miller’s research on short-term memory (STM) capacity is that he did not specify the size or nature of each “chunk”. Simon (1974) found that STM capacity varies with chunk size; participants could remember fewer large chunks, like 8-word phrases, compared to simple, single-syllable words. This indicates that Miller’s concept of chunking lacks specificity, as it does not account for the variability in STM capacity based on chunk complexity, suggesting that his explanation is incomplete. Although Miller’s research underscores STM’s limited capacity, Simon’s findings highlight the need for a more nuanced understanding that considers how chunk size affects memory limits, which would enhance the validity of memory research.
LIMITATION: Individual differences in STM capacity
A limitation of research into short-term memory (STM) capacity is that individual differences, such as age, can significantly affect results, making it difficult to generalise findings. Jacobs found that digit span recall increased steadily with age, with 8 year olds remembering an average of 6.6 digits and 19 year olds recalling an average of 8.6 digits. This suggests that either brain capacity increases with age, or that older individuals develop more effective memory strategies to enhance their digit span. Consequently, STM capacity research should be generalised cautiously, as individual differences like age influence memory capacity, potentially limiting the validity of broad conclusions.
LIMITATION: Findings of STM capacity research lack ecological validity
A limitation of research into short-term memory (STM) capacity is that the findings lack ecological validity, as the research often takes place in artificial settings. Jacobs and Miller used meaningless words, numbers, and objects to test participants’ recall, which does not accurately reflect real-world memory usage. In everyday life, memory typically involved information with personal significance, such as remembering birthdays or daily tasks, which may engage memory systems differently. Therefore, the lack of mundane realism in these lab-based experiments suggests that their findings should only be generalised to real-world memory applications with caution, as they may not fully capture how STM operates in meaningful contexts.
LIMITATION: Peterson study may have measured displacement
A limitation of Peterson and Peterson’s research is that it may have measured displacement rather than trace decay, which undermines the construct validity of the study. Participants were required to count backwards in 3s or 4s as a distraction task, which is a process that may have overwritten the trigrams in memory, leading to displacement rather than merely preventing rehearsal. Reitman (1974) addressed this by using auditory tones instead of numbers and found that STM duration was longer, suggesting that rehearsal prevention alone does not account for STM decay. This implies that P&P’s results may lack validity due to methodological flaws that inadvertently impacted memory trace duration.
STRENGTH: Bahrick’s results have higher ecological validity
A strength of Bahrick’s results is that they have higher ecological validity than Peterson and Peterson’s research into duration. This is because participants’ memory was being tested on their own high school classmates, which means that the task had higher mundane realism. The results are therefore likely to be more generalisable to other settings. However, the issue with this study is that there were more confounding variables. For example, some participants may have frequently looked at their yearbooks while others did not, meaning that the internal validity of the results are compromised as the researchers may not have been accurately measuring the impact of time on LTM recall. It can therefore be argued that Bahrick’s research has high ecological validity but may have low internal validity, which should be taken into consideration when generalising the findings.
STRENGTH: Baddeley’s research demonstrates separate stores
A strength of Baddeley’s research into coding is that it provided evidence for distinct and separate memory stores in short-term memory (STM) and long-term memory (LTM). Baddeley’s findings showed that STM relies on acoustic coding, while LTM primarily uses semantic coding. This distinction supports the idea that STM and LTM operate independently with unique coding methods. This discovery was pivotal in the development of the multi-store model of memory (MSM), which became a foundational theory in cognitive psychology by outlining different memory processes. As a reliable finding that has stood the test of time, Baddeley’s research enhances the validity of the MSM and led on to his development of the working memory model, which significantly influenced memory models and research.
LIMITATION: Contradictory research evidence
A limitation of Baddeley’s findings on the encoding of STM is the existence of contradictory research evidence. Brandimote et al. (1992) demonstrated that participants used visual encoding in STM when given a visual task and prevented from engaging in verbal rehearsal prior to recall. Additionally, Nelson and Rothbart (1972) provided evidence of acoustic encoding in LTM, suggesting that memory encoding may be more flexible than Baddeley proposed. This indicates that encoding in STM is not exclusively acoustic, nor is LTM encoding solely semantic, challenging the universality of Baddeley’s claims. Therefore, the generalisability of Baddeley’s findings is limited, as they may not fully account for the variability in encoding strategies across different memory tasks, raising questions about the validity of his conclusions in diverse contexts.
LIMITATION: Baddeley’s findings lack ecological validity
A limitation of Baddeley’s research is that the findings lack ecological validity as the research was carried out in a lab setting, so they must only be generalised with caution. 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 daily activities. Therefore, as the task Baddeley used lacked mundane realism, the results may not reflect how memory is used in the real world, so lack ecological validity.
