Key study: Working memory and a dual task study on chess (Robbins et al. 1996)

Looking for a study that supports the working memory model? Here’s a good one.

Working memory is the stuff we’re thinking about right now. The working memory model (WMM) was an elaboration of the multi-store model of memory (MSM) as it zooms in on the short-term store and explains how our short-term (working) memory actually works. If you can comprehend what working memory is and you can diagram the model, the next step is to understand the supporting evidence. Let’s look at one study that supports the working memory model. 

Before we look at the study, let’s quickly review the model. The WMM states that current thoughts (our working memory) are controlled by the central executive. It’s like “a little boss in the head” that controls the slave systems. Those slave systems are the visuospatial sketchpad and the phonological loop. The sketchpad is responsible for visual information, while the phonological loop is audio information. The following study is evidence that these two slave systems are seperate and different from one another. This is a major claim of the working memory model. It’s similar to the multi-store model’s claim that short-term and long-term memory are different.

Baddeley and Hitch’s working memory zooms in on short-term memory to explain what’s happening when we’re thinking about stuff.

One problem with the model so far is that it doesn’t explain why sometimes people can appear to keep heaps and heaps of information in their working memory, like actors in a Shakespearean play or memory champs who can remember random orders of hundreds of decks of cards. To explain this, the episodic buffer was introduced into the model. This is a place where information from long-term memory is kept until it’s needed. So the next two lines in an actor’s Shakespearean monologue are in their working memory, while the rest of the monologue they need to remember sits behind the curtain in the episodic buffer waiting for its entrance.

Dual Task Studies 

Which is harder – trying to memorise chess piece arrangements while saying “the” repeatedly or while also trying to type the same 4 numbers on a keyboard over and over? If you know the answer, you understand the working memory model.

When using studies to support a theory, it’s import to know what part of the theory the study is relevant to. It’s not often that one study will support every single claim of a theory. Dual task studies test the claim that there are two separate systems for visual (sight) and audio (sound) memories. The dual task paradigm is an experimental procedure that requires participants to think about unrelated visual and verbal information at the same time. For example, start singing your favourite song and now picture yourself in the mirror singing that song. This is easy because you’re using the two different slave systems. They are separate from each other so your working memory isn’t overloaded (we can only think about four things at any one time). Now try singing your favourite song and writing down the lyrics to a different song. This is much, much harder. Why? They’re both using your phonological loop and it’s maxing out its small capacity. The fact that doing two tasks that use the same slave system is harder than two tasks that use different slave systems is evidence for the fact that these are separate systems.

Exam tip: Don’t use everyday examples like the one I’ve given you above. Remember your purpose and audience. I use these examples to help you understand this tricky concept. In your exams and essays, you’re writing to show you’re a brilliant psychologist who can explain tricky concepts using proper academic language and empirical evidence (studies) not anecdotal examples. Your audience (your teacher and examiner), don’t need this stuff explained in simple terms as they already know it. 

Key Study: Playing Chess and Working Memory (Robbins et al. 1996)

Aim: 

• The psychologists wanted to “…apply the working-memory model to the issue of the nature of thought processes occurring in chess players.” In other words, they wanted understanding the thinking of chess players better by using the working memory model.

Methods:

• Participants were 20 male chess players from Cambridge, UK, ranging in ability from casual chess players to grand champions.
• The researchers wanted to see if memory recall would be affected by processing interfering information. For example, would having to process extra visuo-spatial information interfere with working memory capacity?
• The participants were asked to view an arrangement of pieces on one chess board for ten seconds. This board was on their left as they sat down facing forward. After this ten seconds they then had to try to recreate the arrangement they had just seen on a different chess board on their right. This involved them having to recreate the arrangement using their working memory.
• The independent variable in this experiment was the type of distracting information they had to process while they were completing this task. In one condition, the participants’ phonological loop was interfered with as they had to repeat the word “the” every second to the rhythm of a metronome. They were required to repeat the word during the ten seconds watching the board and learning the arrangement (using their phonological loop), as well as the time it took them to recreate the arrangement on the new board.
• In another condition, their visuospatial sketchpad was interfered with as they had to type into a simple keyboard (4×4 numbers) that was out of sight under a table. They were required to type with one hand in a particular order, while they were arranging the pieces with another hand. This would have required them using their visuospatial sketchpad.

A simple 4×4 keyboard like the one used in the experiment.

Results:

• The results showed that there was a far greater reduction in scores of accurate recall of chess positions when the participants’ visuospatial processing was interfered with during the keyboard task. Their average score for memory of the chess pieces was around 4/25 in this condition, compared to around 16/25 for the phonological interference.

Conclusions:

These results provide evidence for the existence of separate slave systems that process different information during working memory tasks. The memory of the chess pieces and the ability to arrange them in the correct order again requires visuospatial memory. If there was one system of working memory, there would be the same influence of scores on the memory of the chessboard regardless of the modality of interference – whether it was audial or visual. The fact that visuospatial interference had a far greater detrimental effect on visuospatial memory of the chessboard suggests that there are different systems for processing different information.

This study is one of many that has employed the dual task paradigm to investigate the existence of different components within short-term memory, namely the phonological loop and the visuospatial sketchpad. Differing effects on cognition based on modality provides some evidence for Baddeley and Hitch’s claim that our sensory store is comprised of different components that process different types of information.

References

Travis Dixon

Travis Dixon is an IB Psychology teacher, author, workshop leader, examiner and IA moderator.