Working Model of Memory

Baddeley and Hitch (1974) developed the Working Memory Model (WMM), which focuses specifically on the workings of short-term memory (STM).

Atkinson and Shiffrin’s Multi-Store Model of memory (MSM) was criticized for over-simplifying STM (as well as LTM) as a single storage system, so the WMM alternative proposed that STM is composed of three, limited capacity stores:

Central Executive

  • Think of the central executive as the boss that makes decisions about which info deserves attention and which should be ignored.
  • It is modality free, which means that is can receive info from any of our senses
  • The boss also selects strategies for dealing with problems (phonological loop or visuo-spatial sketchpad), but like any person in the company, the boss can only do a limited number of things at the same time (limited capacity) i.e. it can only process what is is paying attention to.
alan-sugar

Think of the central executive as Alan Sugar. He decides what is important and then delegates the tasks to his assistants.

Phonological Loop

The phonological loop is one of the slave systems controlled by the central executive. It deals with auditory / sound information or deals with both written and spoken material. The phonological loop can be subdivided into the phonological store (inner ear) and the articulatory process (inner voice)

Phonological Store (Inner Ear) Stores acoustic items (words that you hear) in speech form

Articulatory Control Process (Inner Voice) Allows for sub-vocal repetition of items in the phonological store, otherwise known as maintenance rehearsal. It’s capacity is believed to be 2 seconds worth of what you can say.

Visuo-Spatial Sketchpad

The visuo-spatial sketchpad deals with visual and spatial tasks (like planning a journey to school in your head). It has a limited capacity, 3-4 objects. It also consists of two sub-components:

Inner (eye) Scribe – Deals with the arrangement of objects in the visual field and is able to manipulate them.

Visual Cache – Stores visual information (e.g. form, shape and colour).

Episodic Buffer

Baddeley added the third slave system in 2000 because it has been suggested that the WMM needed a general store to operate correctly. The EB explains how it is possible to temporarily store information combined together from the Central Executive, the phonological loop, the visuo-spatial sketchpad and long term memory. The EB brings info from phonological loop and visuo-spatial sketch pad together to form a single memory and adds a time frame (episode)

The also EB tries to correct problems caused by the limited capacity of both the phonological loop and the Visuo-spatial sketchpad, as well as problems with Central executive storage of visual and acoustic info. The EB also has a limited capacity of around 4 chunks of information, according to Baddeley.

Research – Evidence

Baddeley & Hitch – Dual process tasks:

The WMM stemmed from research using a ‘dual-task technique’ whereby performance is measured as participants perform two tasks simultaneously. The following observations provided evidence to suggest different, limited-capacity STM stores process different types of memory:

  • If one store is utilised for both tasks, then task performance is poorer than when they are completed separately, due to the store’s limited capacity
    • E.g. repeating “the the the” aloud and reading some text silently would use the articulatory-phonological loop for both tasks, slowing performance.
  • If the tasks require different stores, performance would be unaffected when performing them simultaneously
    • E.g. repeating “the the the” aloud whilst performing a reasoning task (requiring attention true or false quiz, i.e. the central executive), or whilst learning a collection of images (using the visuo-spatial sketchpad).

Baddeley (1975)

Baddeley used a repeated measures design where he showed participants a collection of short words, one word at a time. He then measured how many they could recall. He then asked the same participants to learn a set of longer words, which they then recalled.

Findings: Participants had poorer recall in the longer words compared to the shorter words.

Conclusions: It seems that the phonological loop holds the amount of information that you can say in 2 seconds. This makes it hard to remember a list of long words such as ‘association’ and ‘representative’ compared to shorter words like ‘harm’ and ‘twice’ and therefore inhibits rehearsal of longer words!

Evaluation of the Working Memory Model – Theory: SAUNDERS

  • Alternative explanation – better than MSM: The WMM provides an explanation for parallel processing (i.e. where processes involved in a cognitive task occur at once), For example, driving and talking at the same time. This is more accurate than the MSM as they do not consider this in their theory. The MSM sees memory as moving from one store to the next, and these stores are simplistic. Where as the WMM shows that not only do we have different types of STM, but that we can use these different types simultaneously.
  • Research to support: Case study research: The case study reported that brain-damaged patient KF could still recall visual information using his STM but struggled with auditory and verbal information, making conversation difficult.  This suggests that his phonological loop had been damaged, leaving all other areas of memory intact. Baddeley (1986) also found that patients with damage to their frontal lobe had problems concentrating suggesting damage to the central executive because they find it difficult to direct their attention.
  • Empirical research to support: Evidence supports the existence of separate stores in STM through brain scanning evidence Braver et al gave tasks that involved the Central executive to Ppts while they were having a brain scan. They found that there was greater activity in the prefrontal cortex. Other research using PET scans has found that different parts of the brain are activated when doing a visual task compared to a verbal task. This supports the WMM because it provides evidence that the CE, PL and VSS exist as separate systems within the brain infrastructure.
  • Useful applications: Baddeley’s research into dual processing tasks can be used to support law changes such as driving whilst using a mobile phone. Baddeley found that you cannot do two visual tasks at the same time because it overwhelms the capacity of your VSS. Therefore his research has been essential in saving lives and helping to promote laws that prevent car accidents that happen through texting and driving. Furthermore, Baddeley’s research into the word length effect highlights that we can only manage small chunks of information at a time. His research found that participants were far more likely to recall a list of short words compared to longer words. This means that we should try to learn things in small chunks to ensure we can try and maintain it in our STM.
  • Research to support uses Lab Experiments: The model was developed based on evidence from laboratory experiments, so confounding variables could be carefully controlled to produce reliable results (that can be replicated) However, Ecological validity – Results from laboratory experiments researching the WMM will often have low ecological validity (i.e. may not relate to real life), as tasks such as repeating ‘the the the’ are arguably not representative of our everyday activities.
  • Reductionist – Despite providing more detail of STM than the multi-store model, the WMM has been criticised for being too simplistic and vague, e.g. it is unclear what the central executive is, or its exact role in attention. For example we have no idea of its capacity. Baddeley even quoted ‘the CE is the most important, but the least understood. This discredits the WMM because if it is not fully understood, then it would be difficult to measure and accurately support its existence.