Alan Baddeley is an influential English psychologist who significantly contributed to our knowledge of memory. In 1974 Baddeley proposed a working memory model, a subtype of short-term memory (STM). Such a model could only be developed after Baddeley had conducted several studies on the topic, among which one can find the famous 1966 study. This explanation reviewed this study and assessed its contribution to our current knowledge of long-term memory (LTM) and STM.
- The explanation first present's Baddeley's (1966) Short-Term memory ideas.
- Then the study conducted by Baddeley is presented in terms of its research question, hypotheses and design.
- The results are then discussed, and the study's main conclusion follows.
- The overall contribution of Baddeley to our knowledge of memory is then presented.
- Last, the explanation offers a critical assessment of the strengths and weaknesses of the study.
Baddeley (1966) Short-Term Memory
Before developing the Working Memory Model, Baddeley studied both LTM and STM.
LTM refers to the semi-permanent storing of information, while STM resembles the capacity to hold a limited amount of information for a limited amount of time.
Your knowledge of your address reflects LTM, while your ability to remember the details of the appointment you just made before you note them now reflects STM.
Before 1966, Baddeley had already studied memory. He was particularly interested in encoding, which refers to how information is coded or converted to be stored in memory.
Baddeley was interested in whether encoding happened semantically or acoustically. Hypothetically, semantic memories would be stored based on the meaning of the information, coding the concepts and abstract parts of an object or thought. Contrarily, acoustic memories would be stored based on coding sounds.
Baddeley (1966) Study
The study that Baddeley (1966) designed aimed to test whether LTM was encoded acoustically or semantically. To test this theory, participants were provided with different word lists that either sounded similar or meant similar things. Baddeley predicted that if participants could remember more similar-sounding words, LTM would be encoded acoustically. On the contrary, if participants remembered more words with similar meanings, LTM would be encoded semantically.
Research design
The research presented a between-groups comparison. The 72 participants were recruited through opportunity sampling and were randomly allocated to four groups.
Variables
The independent variable (IV) that was investigated had two levels:
Acoustically similar words versus acoustically dissimilar ones.
Semantically similar words versus semantically dissimilar ones.
The dependent variable was the score on a recall test of 10 words (calculates as a percentage). Participants did not only need to recall the words themselves but also the order in which these were presented.
Procedure
Each of the four groups was shown a slideshow including 10 words. The words were displayed for 3 seconds each.
The four groups emerged based on the four levels of the IV. In this way, the groups were the following:
- Acoustically similar words, which included words such as cap, hat, or sack.
- Acoustically dissimilar words which included words such as cow, dad, or led.
- Semantically similar words included words such as big, large, or huge.
- Semantically dissimilar words which included words such as hot, pen, or man.
As you can see from the examples, all words were simple and had one syllable. This was done to avoid that word difficulty would impact the results.
The learning phase was separated from the testing phase by an interference test in which participants had to hear and write numbers.
In the testing phase, participants took part in a recall test. For the recall test, participants needed to recall the words and the order in which they appeared.
This procedure was repeated four times. After the fourth trial, participants took a break and completed an unrelated interference task. To their surprise, they were asked to recall the list of words again after the break.
Baddeley (1966) Results
When calculating the results, the performance of the individuals in groups 1 and 2 was compared, as well as the performance of groups 3 and 4, separately. Further, participants' performance on the 5th trial was analysed to test for forgetting.
The results indicated that:
Acoustically similar words were harder to recall than acoustically dissimilar words. Remembering the words cap, hat, and sack is more difficult than remembering cow, dad, and led.
Semantically similar words were harder to recall than semantically dissimilar words. Remembering the words big, large, and huge is more difficult than remembering hot, pen, and man.
When assessing STM, this is, when comparing trials before the break, the worse performance was for the acoustically similar words.
Performance was overall better on the semantic condition than on the acoustic one.
Fig. 1. Results graph from Baddeley's (1966) original paper
Baddeley's (1966) conclusion
The main conclusion that Baddeley drew from such results is that LTM is encoded semantically. This comes from the fact that performance on the firth condition was better for the semantic condition than for the acoustic one. Further, Baddeley (1966) concluded that STM encoding is acoustic. This was deduced by the fact that performance on the short-term conditions (trials 1-3) was worse for semantically similar words.
Baddeley Findings
Taken together, through the pioneering work of Baddeley, psychologists learned that the encoding of STM and LTM differed from one another. Baddeley's main contribution to our knowledge of memory is that while LTM is encoded semantically, STM is encoded acoustically.
Baddeley (1966) Strengths and Weaknesses
Here there is a critical evaluation of Baddeley's (1966) study.
Baddeley (1966) Strengths
The strengths of the study are:
Since the study was standardised and can easily be replicated, it presents high reliability.
Baddeley used interference tasks to make sure that he was actually measuring long-term memories. This, in turn, increases the internal validity of the findings.
Baddeley and Hitch used this study as supporting evidence for the proposal of the working memory model in 1974, which provides evidence of the implications that these findings had.
It has beneficial implications for real-life scenarios; for instance, students can use these findings to strategise their revision techniques better).
Baddeley (1966) Weaknesses
The weaknesses of the study are:
It was carried out on British students, which makes it ethnocentric. Therefore the research does not consider cross-cultural differences and limits the generalisability of the findings.
The sample included 72 participants, which is not representative of the population and limits the generalisability of the findings.
Given that it is a laboratory study, has low ecological validity; it is unlikely that the procedure is used in everyday life.
Baddeley - Key takeaways
- The research aimed to see whether LTM and STM encoding is semantic or acoustic.
- Participants were allocated into groups and asked to recall a list of words and their order.
- The study found that:
- LTMs are encoded semantically.
- STMs are encoded acoustically.
- The strengths of the study are that it has high reliability and internal validity and research theories applications.
- The weaknesses of the study are that it is ethnocentric, non-generalisable, and has low ecological validity.
References
- Baddeley, A. D. (1966). The influence of acoustic and semantic similarity on long-term memory for word sequences. Quarterly Journal of Experimental Psychology, 18(4), 302–309. doi:10.1080/14640746608400047
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