1. Short-Term Memory & Working Memory
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/19/2018: Lecture 04-4
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2. Lecture probably ends here
Outline
Chunking in WM/STM
Brown-Peterson Paradigm: How long does information last in WM/STM?
Causes of forgetting from WM/STM
The Working Memory (WM) Model
Phonological Loop (PL)
Visuospatial Sketchpad (VSP)
Central Executive (CE)
What is the phonological loop?
Lecture probably ends here
Psych 355, Miyamoto, Spr '18
Chess Masters & Chess Novices: Chunking & WM/STM Memory Span

3. Famous Example of Chunking and/or Recoding Chess Masters versus Chess Novices
Chase and Simon (1973a, 1973b):
Chess masters can remember the locations of a large number of pieces on a chess board even if it is only briefly flashed in front of them.
Chess novices perform much worse on WM/STM retention of chess pieces on a chess board.
Chase and Simon's study is discussed in Chapter 12 of Goldstein (2014, 4th edition). I am discussing it here because it illustrates how chess experts and chess novices differ in their use of memory resources. In particular, chess experts can chunk and recode chess information in ways that novices cannot.
Psych 355, Miyamoto, Spr '18
Overview of Results: (Chess Masters/Novices) x (Meaningful/Random Boards)

4. Chess Masters versus Chess Novices
Master does no better than novice because he can’t chunk.
Master Novice
(b) Random placement
Master Novice
(a) Actual game positions
Actual Game Positions = Chess pieces are arranged as in a real game
Random Placement = Chess pieces are arranged at random; These positions could never occur in a real game.
Psych 355, Miyamoto, Spr '18
Focus on Left Panel: Actual Game Positions

5. Chess Masters versus Chess Novices
Master does no better than novice because he can’t chunk.
Master does better than novice because he can chunk based on strategic relationships.
Master Novice
(b) Random placement
Master Novice
(a) Actual game positions
Chess masters are much better than chess novices at remembering chess positions from real games.
Psych 355, Miyamoto, Spr '18
Focus on Right Panel: Random Arrangements of Chess Positions

6. Chess Masters versus Chess Novices
Master does no better than novice because he can’t chunk.
Master does better than novice because he can chunk based on strategic relationships.
Master does no better than novice because he can’t chunk.
Master Novice
(b) Random placement
Master Novice
(a) Actual game positions
Masters and novices are equally bad at remembering random chess positions (impossible positions) on a chess board.
Psych 355, Miyamoto, Spr '18 ##

7. Summary: Chunking, Recoding, STM Capacity Limits
As we take in information, we reorganize it into larger chunks, and we recode the information into other mental formats.
Knowledge, learning, and past experience help us use our limited-capacity short-term memory more effectively.
Are experiments that study STM capacity limits relevant to everyday life?
In everyday life, we almost never try to remember sequences of unrelated information.
Yes – the capacity limits are always present, even if they are hidden in everyday life by our chunking and recoding strategies.
Psych 355, Miyamoto, Spr '18
Brown-Peterson: How Long Does Information Last in WM/STM?

8. How Long Does Information Last in WM/STM?
Brown-Peterson paradigm – an attempt to measure how long information is retained in STM without active processing.
Preview of Conclusion: Information is lost from WM/STM after 15 – 20 seconds, and sometimes less.
Examples of forgetting from STM: Forgetting what you are doing – suddenly you can’t remember why you picked up a tool or walked into a room, etc. Your intention of what to do next is part of the content of STM – if something bumps it out, you may be temporarily unable to retrieve the intention.
Example: If you remember something you want to do when you get home, but if you don’t write it down, you may forget it and not remember it later.
Psych 355, Miyamoto, Spr '18
The Brown-Peterson Paradigm - Description of the Task

9. Brown-Peterson Paradigm
Brown-Peterson paradigm – an attempt to measure how long information is retained in STM without active processing.
The Brown-Peterson task is the Coglab for this week.
Example of the Task:
Remember three letters:
Count backwards by 3’s from the given number:
Stop counting and report the letters when the experimenter tells you to do so.
P N R
P N R
108
Duration of delay is different on different trials, e.g., 5 second, 10 second, 15 seconds, .....
Psych 355, Miyamoto, Spr '18
Brown-Peterson Paradigm – What Is the Purpose of the Brown-Peterson Task?

10. What is the Purpose of the Brown-Peterson Paradigm?
Brown-Peterson paradigm – an attempt to measure how long information is retained in STM without active processing.
Remember three letters, e.g., “P N R"
Count backwards by 3's from a given number
Report the letters after a delay
Goal: Measure decay characteristics of STM.
Counting backwards by 3’s is an example of articulatory suppression.
Later when we discuss working memory, we will say that counting backwards by 3’s suppresses rehearsal in the phonological loop (PL).
Assumption 1: While you are counting backwards, you cannot rehearse “P N R”.
Assumption 2: Counting backwards by 3's does not interfere with retention of "P N R".
Psych 355, Miyamoto, Spr '18
Results for Brown-Peterson Task – Averaged Results

11. Results for the Brown-Peterson Paradigm
Delay in Seconds
IMPORTANT FACT: These results are averaged over many trials.
Superficially, the results support the hypothesis that without active processing, almost all information is lost after about 15 – 20 seconds.
Keppel & Underwood: Reanalysis for 3rd & 18th Trial
Psych 355, Miyamoto, Spr '18

12. Keppel & Underwood’s Reanalysis of Brown-Peterson Results
Delay in Seconds
Panel (b): Performance on the 1st trial of Brown-Peterson task.
Panel (c): Performance on the 3rd trial of Brown-Peterson task.
Performance at 18 second delay gets worse as subject performs more memory trials!
Psych 355, Miyamoto, Spr '18
Same Graph – Hypothesis That Proactive Interference Causes Forgetting

13. Bottom Line re Duration of Storage in WM/STM
To keep information in WM/STM, you need to actively process the information.
Phonological rehearsal & forming mental images
Associating contents of WM/STM with information in LTM (thinking)
Without active processing, information in WM/STM is lost after 15 – 20 seconds.
In everyday life, information may be lost from WM/STM even more quickly, e.g., new information interferes with the current contents of WM/STM.
Psych 355, Miyamoto, Spr '18
What Causes Forgetting from WM/STM?

14. What Causes Forgetting from WM/STM?
Three hypotheses (not mutually exclusive):
Competition – a new focus of attention draws attention capacity away from current contents of WM/STM. New information pushes aside current contents of WM/STM.
Interference – something you learn or already know conflicts with the retention of other information because it is similar in meaning or form.
Decay – no one has yet proved definitively whether decay occurs.
Psych 355, Miyamoto, Spr '18
Competition Causes Forgetting from WM/STM

15. Competition Causes Forgetting from WM/STM
Suppose that T and X are two different mental tasks to which one can devote attention.
In Brown-Peterson task, T = retention of three letters, e.g., F, L, W, in STM; X = counting backwards by 3's from a designated starting number.
In everyday life, my attention is usually divided between several lines of thought. If some focus of attention becomes especially interesting, other competing foci get less attention, or none.
If, while maintaining X in WM/STM, attention is diverted to some other topic or task Z, then attention to Z can cause part or all of X to drop out of WM/STM.
Psych 355, Miyamoto, Spr '18
Interference Causes Forgetting from WM/STM

16. Interference Causes Forgetting from WM/STM
Interference – something you learn or already know makes it difficult to remember something else.
Retroactive Interference (RI): New learning interferes with recall of previous learning.
Example: What did you see when you walked to school 7 days ago? Everything you have seen since then interferes with access to that memory.
Example: Julie used to go out with Tom and now she goes out with Ted Memory of Julie/Ted interferes with memory of Julie/Tom.
Proactive Interference (PI): Previous learning interferes with recall of new learning.
Example: If you already play tennis, it is harder to learn to play badminton than if you already play basketball .
Example: It is hard to remember where I parked my car today because I have many memories of parking my car in various places.
Psych 355, Miyamoto, Spr '18
Does Decay Cause Forgetting from WM/STM?

17. Does Decay Cause Forgetting from WM/STM?
Results for the Brown-Peterson task looks like it demonstrates that information decays from WM/STM, but there is actually a different, better explanation. [Topic of Section 4, 4/19/2018]
There is no clear evidence that decay from WM/STM occurs, but it is hard to prove that it doesn't occur. [Topic of Section 4, 4/19/2018]
Psych 355, Miyamoto, Spr '18
Overview of the Distinction Between the STM Model and the WM Model

18. Overview of the STM and WM Models
Short-Term Memory (STM)
STM is a single component
Main theoretical issue:
How much information can be stored in STM? How long does it last?
Working Memory (WM)
WM has multiple components
Main theoretical issues:
How is information represented in WM? How is information manipulated in WM?
The issue of the duration and quantity of information storage is still important, but question of how WM manipulates information is the central focus of research.
Psych 355, Miyamoto, Spr '18
Diagram for the Modal Model of Memory (Contrast with WM Model)

19. Modal Model of Memory (circa 1970)
Control Processes
Input
Sensory Memory
Short-Term Memory
Long-Term Memory
Output: Speech/Actions
Psych 355, Miyamoto, Spr '18
Diagram for the Baddeley-Hitch Working Memory Model

20. Baddeley-Hitch Working Memory (WM) Model
Think of the diagram to the right as an expansion & revision of the standard STM model.
Phonological Loop (PL)
Storage of sounds
Rehearsal
Manipulation of verbal information
Visuospatial Sketch Pad (VSP)
Storage & manipulation of visual images and spatial information.
3. Central Executive (CE)
Directs activity within the PL or VSP.
Coordinates activity between PL, VSP, and LTM.
Basic Idea: At least two short-term memory stores, audition (language), visual/spatial.
What justifies the hypothesis that there are separate memory stores?
What justifies the assumption of an executive process.
Psych 355, Miyamoto, Spr '18
Same Slide Without the Emphasis Rectangles

21. Baddeley-Hitch Working Memory (WM) Model
Think of the diagram to the right as an expansion & revision of the standard STM model.
Phonological Loop (PL)
Storage of sounds
Rehearsal
Manipulation of verbal information
Visuospatial Sketch Pad (VSP)
Storage & manipulation of visual images and spatial information.
3. Central Executive (CE)
Directs activity within the PL or VSP.
Coordinates activity between PL, VSP, and LTM.
Basic Idea: At least two short-term memory stores, audition (language), visual/spatial.
What justifies the hypothesis that there are separate memory stores?
What justifies the assumption of an executive process?
Psych 355, Miyamoto, Spr '18
What Justifies the Hypothesis: PL is Part of WM?

22. Thursday, 19 April, 2018: The Lecture Ended Here
Psych 355, Miyamoto, Spr '18