Alan Baddeley on the development of the working memory model

Summary

The speaker shares their journey into researching memory, starting with a grant to study long-term and short-term memory at the University of Sussex. They explore the limitations of the Atkinson-Shiffrin model, which was prominent at the time but faced criticism due to new findings in neuropsychology and cognitive research. Key discoveries, like Craik and Lockhart's levels of processing and case studies of patients with distinct memory impairments, led to questioning the model's assumptions. The speaker introduces their own working memory model with three components: the central executive, phonological loop, and visuospatial sketchpad, which became influential in memory research.

Takeaways

• 🧠 The speaker transitioned from psychology to a teaching position at the University of Sussex and applied for a grant to study the relationship between long-term and short-term memory.
• 📝 The research focused on the challenges of short-term memory models at the time, particularly the popular Atkinson and Shiffrin 'modal model' of memory.
• 📚 The Atkinson and Shiffrin model assumed that information passed through sensory buffers into a unitary store, acting as working memory.
• 💡 The concept of working memory, introduced in the 1960s, was seen as a temporary system used for cognitive tasks like reasoning and learning.
• 🔍 The modal model faced criticism for suggesting that holding information in short-term memory improves learning, which was proven ineffective by studies on deeper levels of processing.
• 🧑‍⚕️ Neuropsychological case studies, such as patient HM, highlighted issues with the model, showing that short-term memory impairments did not always affect learning and intelligence.
• 🔄 The discovery of a double dissociation between short-term and long-term memory deficits in different patients challenged the unitary view of memory systems.
• 📊 Experiments involving tasks like digit span showed that using working memory resources slowed performance but did not entirely disrupt cognitive tasks like reasoning.
• 🛠️ The researchers proposed a multi-component model of working memory, consisting of a central executive, a verbal component (phonological loop), and a visual-spatial sketchpad.
• 📖 The 1974 paper 'Working Memory' introduced this model, which became highly influential in the study of memory, even though full understanding of working memory remains elusive.

Q & A

What motivated the speaker to apply for a research grant?

The speaker's boss at the University of Sussex suggested applying for a grant, which led the speaker to pursue research on the relationship between long-term and short-term memory.

Who did the speaker appoint as the postdoc for the research, and what was the focus of the project?

The speaker appointed Graham Hitch as the postdoc, and the research focused on the relationship between long-term and short-term memory.

Why had short-term memory research become unpopular at the time?

Short-term memory research had become unpopular because it had grown messy with many similar models that lacked clear distinctions, and there was dissatisfaction with the prevailing model by Atkinson and Shiffrin.

What was the Atkinson and Shiffrin modal model, and why was it criticized?

The Atkinson and Shiffrin modal model suggested that information flows through sensory buffers into a unitary store acting as working memory. It was criticized for assuming that learning improved just by holding information in memory, which was later proven inefficient.

How did Craik and Lockhart’s levels of processing theory challenge the Atkinson and Shiffrin model?

Craik and Lockhart showed that learning was more effective when information was processed deeply, rather than just held in memory. For example, thinking about a word’s meaning helped retain it better than just repeating it.

What neuropsychological evidence challenged the separation between short-term and long-term memory?

Studies on patients, like HM, who had impaired long-term memory but intact short-term memory, challenged the separation. Other patients had intact long-term memory but impaired short-term memory, showing a double dissociation that questioned the existing models.

What is meant by a ‘double dissociation’ in memory research, and why is it significant?

A double dissociation occurs when one group of patients can perform one task but not another, and a complementary group shows the opposite pattern. This is significant because it provides strong evidence for the separation of cognitive functions, such as short-term and long-term memory.

How did the speaker’s team attempt to simulate the effects of brain damage in healthy subjects?

The speaker’s team simulated the effects of brain damage by giving healthy subjects tasks that used up working memory, such as holding and repeating sequences of digits while performing reasoning, learning, or comprehension tasks.

What were the findings of the experiment involving healthy subjects performing dual tasks?

The experiment found that while performance was slower as the number of digits held increased, the error rate remained constant. This suggested that short-term memory alone could not fully explain working memory function.

What components did the speaker propose to account for the limitations of existing memory models?

The speaker proposed three components: a central executive for attentional control, a verbal component (phonological loop) for short-term memory, and a visuospatial sketchpad for visual memory, forming the basis of the working memory model.