About Short-Term Memory

This is a series of blog posts about the learnings and discoveries I made while studying Cognitive Psychology at the University of Berkeley, California. It will introduce you to the basic concepts of human cognition; attention, memory, categorization, semantic organization, language, problem solving and decision making.

Marc-Oliver
Jul 24, 2017 · 4 min read

Let me introduce you the the concept of short-term and working memory by describing a specific situation in three phases.

Phase 1: Our protagonists, Alex and Chris, are about to encounter and recognize each other on a busy street in downtown New York.

During this stage, the Sensory Store/Memory is used. It works as a rapid buffer that keeps available for a brief moment all sorts of incoming sensory stimuli that we would normally miss . This gives our two protagonists, Alex and Chris, a little bit more time to recognize each other, especially since their encounter is so unexpected. Let us assume, Chris takes full advantage of his Sensory Memory and intentionally accesses what he just noticed out of the corner of his eye: a familiar face. At this point, Chris’s Central Executive component already demanded some information about Alex from his Long Term Memory and put it into his Episodic Buffer (STM), so that he can manipulate/update the data in the following conversation.


Phase 2: Alex remembers Chris

Let us assume that Alex’s mind was occupied and completely ‘somewhere else’ at the time that Chris walked up to him. At first, Alex simply did not recognize his old friend. His Visuospatial Sketchpad, Phonological Loop and his Central Executive Component were visualizing a plan of his new home, counting the rooms and identifying how many windows he needed to order. Although, his Sensory Memory kept recording a person walking towards him, he paid no attention whatsoever until Chris started to call his name. At this point, Alex’s Central Executive Component switched the focus of attention to Chris. ‘It’ noticed a familiar auditory code; Chris’s voice.


Phase 3: Alex and Chris exchanging information/news

During this stage, both Alex and Chris are constantly receiving and encoding new verbal and visual information codes from each other. Based on Baddeley’s revised Working Memory Model (Alan D. Baddeley, 1974), the Phonological Loop (PL) maintains and manipulates language and the Visuospatial Sketchpad (VSSP) deals with visualisations. Both components also have access to what is stored in the Long Term Memory, so there is a constant refreshing of information codes. Apparently, the Episodic Buffer (the STM in Baddeley’s Model) pulls and holds information chunks from different modalities together, until they get passed on, decay or other new incoming information interferes with it. The Central Executive Module, which I mentioned earlier, seem to control and shift the attention to the different components of the working memory, respectively makes decisions.

So while Alex is talking to Chris, his Central Executive Component blended out most distractors from outside, but also shifted his attention away from his previous task of counting the windows for his new home. He now focuses (his attention) on just Chris. His eyes keep scanning his old friend, comparing the images he has in his Long Term Memory with new incoming visual codes and refreshing them when necessary. The Visuospatial Sketchpad is helping Alex to maintain and to manipulate all the visual information. The same is true for incoming verbal information, leveraging Alex’s Phonological Loop. When they talk about the new neighbourhoods they now both live in, Chris and Alex immediately form a visual map from their verbal instructions, leveraging all four of Baddeley’s components at the same time: The Central Executive is orchestrating the resources and the Episodic Buffer keeps combining, storing and refreshing information snippets from both the VSSP and PL. The Long Term Memory adds architectural landmarks and familiar places they both been to.

Although, Baddeley’s revised Model from Reed’s book (‘Cognition’, Stephen K. Reed, 2012) does not account for other types of memory codes beyond the visual and the verbal (due to his research focus?), Baddeley believes that other modalities work in a similar way and follow the same ‘working’ principles and logic.

In summary – all memory systems mentioned in Reeds book seem to have three main functions. The first one is encoding. The second one is storage and the third function is retrieval. What is fascinating about the Working Memory is it’s capability to direct our attention. You can probably compare it best with the role of a conductor of a large orchestra. The primary duties of the conductor are to set the tempo, ensure correct entries by various members of the ensemble, and to shape the phrasing where appropriate. Basically exactly what I have described in Phase 2.


Related academic resources:

  • Alan D. Baddeley, 1974 [Link]
  • Andre Szameitat, 2017 [Video]
  • Stephen K. Reed, 2012 [Link]
  • Bart Aben, Sven Stapert and Arjan Blokland [Link]
  • Berkeley Course Material, Dr Christopher Gade

The Versatile Designer

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Marc-Oliver

Written by

Senior UX Manager @Appnovation, Canada. Writes about Cognitive Psychology, Behavioural Economics & Platform Design. Creator of https://axurewidgets.com.

The Versatile Designer

The hidden stories every product designer should know about markets, products & consumer behavior.

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