Baddeley (1966b) Working Memory (Edexcel A-Level Psychology): Revision Notes

Baddeley (1966b) Working Memory

Overview

Alan Baddeley, a prominent memory researcher, sought to examine whether long-term memory (LTM) and short-term memory (STM) represented distinct systems or existed on a continuum. Previous investigations into STM and LTM employed different research techniques, making direct comparison difficult. Baddeley proposed that determining whether these memory systems were different or the same required using identical research methods for both. He designed an investigation to explore how both semantic (meaning-based) and acoustic (sound-based) coding affected both short-term and long-term memory.

Aim

To investigate the influence of acoustic and semantic word similarity on learning and recall in short-term and long-term memory.

Procedure

Baddeley designed a laboratory experiment to test sequential recall of acoustically and semantically similar word lists. Three different experiments were conducted; experiment three provides the focus here.

Participants

Men and women were recruited from the Applied Psychology Research Unit subject panel. Participants were assigned to one of four list conditions using an independent groups design.

Materials

Four lists of 10 words were created:

• List A: Contained 10 acoustically similar words (e.g. man, can, cat, map)
• List B: Contained 10 acoustically dissimilar words matched in terms of frequency of everyday use to List A (e.g. pit, few, cow, mat)
• List C: Contained 10 semantically similar words (e.g. great, large, big, broad)
• List D: Contained 10 semantically dissimilar words matched in terms of frequency of everyday use to List C (e.g. good, huge, deep, late)

Procedure steps

1. Each list of 10 words was presented via projector at a rate of one word every three seconds in the correct order
2. After presentation, participants completed six tasks involving memory for digits
3. Participants were then required to recall the word list in one minute by writing down the sequence in the correct order
4. This process was repeated over four learning trials
5. The word list in random order was displayed on a card in the room throughout (as this was not a test of learning words, but of sequence order)
6. After the four learning trials, participants were given a 15-minute interference task involving copying eight digit sequences at their own pace
7. Following the interference task, participants were given a surprise retest on the word list sequence

Procedure table

Hearing test	Learning trials				Interference task	Retest
Listening and copying each word presented in random order from the list	Trial 1: Visual presentation of list followed by a 6 eight-digit sequence recall task, followed by recall of the list	Trial 2: Visual presentation of list followed by a 6 eight-digit sequence recall task, followed by recall of the list	Trial 3: Visual presentation of list followed by a 6 eight-digit sequence recall task, followed by recall of the list	Trial 4: Visual presentation of list followed by a 6 eight-digit sequence recall task, followed by recall of the list	Copying sequences of digits	Recall of the word list in the correct order

Findings

Recall of the acoustically similar sounding words was worse than the dissimilar sounding words during the initial phase of learning, particularly during trial two. However, recall of the similar and dissimilar sounding words was not statistically significant when tested for long-term memory. This demonstrates that acoustic encoding was initially difficult but did not affect long-term memory recall.

Participants found the semantically similar words more difficult to learn than the semantically dissimilar words, and recalled substantially fewer semantically similar words in the retest.

Conclusion

The finding that participants found it more difficult to recall List A (acoustically similar words) in the initial phase of learning suggests that short-term memory is largely acoustic. Therefore, acoustically similar sounding words were more difficult to encode in STM.

Later retest recall of List C (semantically similar words) was impaired compared to all other lists because they were semantically similar, suggesting that encoding in long-term memory is largely, but not exclusively, semantic.

Evaluation: Strengths

Scientific methodology: The study was conducted in a controlled laboratory environment with a standardised procedure. Therefore, the study can be regarded as replicable and the reliability of the results can be established.

Cause and effect relationship: Due to the highly controlled nature of the experiment, Baddeley established a cause and effect relationship between the independent variable (semantic or acoustic word list similarity) and the dependent variable (long-term memory). This provides strong evidence for the different encoding processes in STM and LTM.

Controlled variables: Some participants received a list of same frequency words as a baseline for recall comparison. This controlled for potential confounding variables and ensured that any differences between the experimental and control lists resulted from similarity rather than other factors affecting recall.

Evaluation: Weaknesses

Lack of mundane realism: Laboratory research employs experimental techniques that are not typical of how memory is used in everyday contexts. We do not often learn lists of random monosyllabic words. Therefore, the ability to generalise these findings to everyday contexts is questionable. However, memory researchers would argue that to understand memory, we need to remove the context in which normal memory is used and simplify the nature of the information being learned in order to isolate the aspects of memory we are concerned with.

Exaggerated rehearsal: The experiment relied heavily on rehearsal during the four learning trials for information to become established in long-term memory. The very concentrated nature of rehearsal is likely to have exaggerated this memory process, with the result being an artefact of the experimental procedure. Under normal conditions, we would not be expected to use rehearsal in such a contrived way, so this study lacks mundane realism.

Limited ecological validity: The artificial nature of the task (learning lists of similar-sounding or similar-meaning words) does not reflect how memory operates in real-world situations, where context, emotion, and personal relevance play important roles in encoding and retrieval.

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