Cognitive Psychology The working Model of Memory By Baddeley and Hitch (1974)

Learning objectives Understand what is meant by the concept of working memory. Describe the working memory model and understand the functions and limitations of its components. Describe and evaluate the evidence on which the working model is based. Understand the strengths and weaknesses of the model.

Background to the WMM Baddeley and Hitch (1974) believed that there was more to STM than in the multi-store model (i.e. more than just being one store house).

The components of the WMM A complex and flexible system with different components

A MORE ACTIVE MODEL OF MEMORY

3 main components The central executive (supervisor) Has overall control Limited capacity Can process information from any sensory modality

Central Executive Responsible for a range of control processes e.g. setting task goals, monitoring and correcting errors, starting rehearsal process, switching attention between tasks, inhibiting irrelevant information Retrieving information from LTM Coordinating activity needed to carry out more than one process at a time.

Two slave systems The slaves to the CE can be used as storage systems Which frees up some of the CE’s capacity to deal with more demanding information processing tasks. The slave systems have separate responsibilities and work independently of one another.

1. Phonological Loop (the inner voice) has limited capacity A temporary storage system for verbal information in a speech-based form.

2. The visuo-spatial sketchpad The inner eye Limited capacity Temporary memory system for holding visual and /or spatial information

Revised model (1999) Phonological loop now = passive storage system called Phonological store which is linked to a rehearsal system called The Articulatory Loop Maintained by subvocal repetition. The visuo-spatial sketchpad = passive visual store called Visual cache (collection of data) which is linked to an active ‘inner scribe’ that acts as a rehearsal mechanism.

The dual task method To test the function of STM, Baddeley and Hitch asked participants to perform: A reasoning task (sentence-checking) While reciting a list of 6 digits. According to the multi-store model the capacity of the STM would be taken up with the digit task.

Recite the six digit number aloud while ticking True or False 1. B is followed by A BA 2. A is preceded by B AB 3. A is not followed by B BA 4. B follows A AB 5. B does not follow A BA 6. B is not followed by A AB 7. A follows B AB 8. B is not preceded by AAB 9. A is not followed by B BA 10. B does not precede AAB

Findings Participants made very few errors on either task (although the speed of sentence checking was slightly slower than when done on its own).

Conclusions Baddeley and Hitch concluded that STM must have more than one component and Must be involved in processes other than simple storage, e.g. reasoning, understanding and learning. STM is a kind of workspace where a variety of operations can be carried out on both old and new memories.

A MORE ACTIVE MODEL OF MEMORY

Very important Two tasks can be carried out at the same time as long as They are being carried out by different modalities (parts of the memory system). LTM is a more passive store for previously learned material. The ACTION is in the STM.

Evidence for the phonological loop Baddeley et al. (1975) Visual presentations of word lists for a brief time Participants asked to write them down in serial order. Condition 1 – lists consisted of 5 words familiar, one-syllable English words, e.g. harm, wit, twice. Condition 2 – 5 words, polysyllabic, e.g. organisation, university, association.

findings More short words were recalled This was called ‘the word length effect’ Conclusion Capacity of the loop is determined by the length of time it takes to say a word rather than by the number of items. The estimated time was 1.5 seconds

Method Laboratory experiment using a repeated measures design Evaluation Well controlled Longer words may be less familiar than short words. This could have affected the recall rather than the length. No ethical issues if fully informed consent obtained.

The word length effect under articulatory suppression Participants were given a task that would usually make use of the articulatory loop Asked to repeat a meaningless chant aloud e.g. la-la-la The word length effect disappeared and recall for short words was no better. This suggests that a verbal rehearsal system is important and when suppressed, processing has to take place elsewhere (maybe the central executive)

Evidence for the visuo-spatial sketchpad The visual store also has limited capacity. Shepard and Feng (1972) asked participants to imagine folding flat shapes in order to make a cube. They had to decide whether the arrows would meet head on.

findings The time taken to make the decision was related to the number of folds they would have had to make if they had actually been doing the task. Visual images work in a similar way to real life perception. People are likely to find it difficult to do two tasks simultaneously if they both use the visuo-spatial sketchpad.

Research: Baddeley et al Participants were given a tracking task (following a spot of light with a pointer around a circular path while imagining block capitals such as H, T, F and E.

Participants were asked to start at the bottom left-hand corner, to respond to each angle with a ‘yes’ if it included the bottom or top line of the letter and a ‘no’ if it did not. F H

findings Participants had enormous difficulty in tracking the spot of light and accurately classifying the corners. The two tasks were competing for the same limited resources of the visuo- spatial sketchpad. This is supported by the fact that participants could carry out the tracking task while performing a verbal task.

Logie (1995) Suggested that the visual cache stores information about visual form and colour The inner scribe processes spatial and movement information.

Klauer and Zhao (2004) supported this Participants carried out one of two tasks: A visual task A spatial task At the same time they were asked to do either A spatial interference task A visual interference task No secondary task (control condition)

findings Performance of the spatial task was much poorer for those carrying out a spatial distractor task at the same time compared with those doing the visual distractor task and vice versa. PET scans show evidence for separate systems. Brain activity differs. More activity in the left half for visual More activity in the right half for spatial

Evidence for central executive Critical role in attention, planning and coordination. Most flexible component of the working memory. More difficult to find evidence for. Easier to study the slave systems. Research on the CE tends to focus on the different functions.

Baddeley (1996) Investigated the functions of the CE in selective attention and switching retrieval plans. Participants were asked to generate random strings of digits by pressing numbered keys on a keyboard.

Try this (if you have a computer) Think of a sequence of eight digits that show no systematic pattern (Note that patterns easily emerge so this is difficult). At the same time: Recite the alphabet Count from 1 Alternate between letters and numbers (A1B2C3D4E5F6 etc)

findings Baddeley found that the generated digit string became considerably less random in Condition 3 when particpants were switching from alphabet to numbers at the same time. Baddeley concluded that both the random number generation task and the alternation task were competing for the same central executive resources.

Evaluation of the working memory model A very influential model Accepted by cognitive psychologists in preference to the idea of a STM store. More plausible than the multi-store model because it explains the STM in terms of active process rather than passive storage alone. Verbal rehearsal is accepted as one optional process within the articulatory loop rather than the only way to transfer information to the LTM.

More positives of the WMM It can account for some of the findings that the MSM finds difficult to explain. Research support comes from dual-task studies although KF could remember visual but not verbal stimuli in STM – supports the idea of at least 2 separate systems in the STM.

Brain scans show different areas of the brain are used for visual and verbal tasks which supports the WMM. The role of the CE is not fully understood and it is likely to be comprised of more than one component. Fails to account for musical memory as we are able to listen to instrumental music without impairing performance on other acoustic tasks.