1. Decay in Short-Term Memory (STM) then: The Working Memory (WM) Model
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/21/2016: Lecture 04-4
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2. Lecture probably ends here
Outline
What causes forgetting in STM?
Decay
Interference (proactive interference and retroactive interference)
Measurement of decay in STM: The Brown/Peterson paradigm
Working memory (WM) model of Baddeley & Hitch
Phonological loop
Visuospatial sketch pad
Episodic working memory
Evidence for the phonological loop
Lecture probably ends here
Psych 355, Miyamoto, Spr ‘16

3. What Causes Forgetting from WM/STM?
Why is information lost from STM? How long does information last in STM without active processing?
Two hypotheses
Decay – representations of information simply "fall apart."
Interference – other information "bumps" information out of STM.
Brown-Peterson paradigm – an attempt to measure how long information is retained in STM without active processing.
General Conclusion: Without active processing, all information is lost after 15 – 20 seconds.
What causes the loss of information?
Interference - It is certain that this is one cause.
Decay - hard to prove convincingly that decay occurs; maybe it does.
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.
The Brown-Peterson Paradigm - Example
Psych 355, Miyamoto, Spr '16

4. 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 this past week’s Coglab.
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
108
Duration of delay is different on different trials, e.g., 5 second, 10 second, 15 seconds, .....
Brown-Peterson Paradigm – Summary of the Task
Psych 355, Miyamoto, Spr '16

5. 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".
Results for Brown-Peterson Task – Averaged Results
Psych 355, Miyamoto, Spr '16

6. 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 '16

7. 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!
Same Graph – Hypothesis That Proactive Interference Causes Forgetting
Psych 355, Miyamoto, Spr '16

8. Keppel & Underwood’s Reanalysis of Brown-Peterson Results
Delay in Seconds
Why does performance at 18 second delay get worse as subject performs more memory trials?
Proactive interference – explained on next slide
Interference – Definition; Proactive & Retroactive Interference
Psych 355, Miyamoto, Spr '16

9. Interference – a Cause of Forgetting
Interference as a cause of forgetting – 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): Old 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 (not tennis).
Example: It is hard to remember where I parked my car today because I have many memories of parking my car in various places.
Experimental Design for Wicken’s Exp Showing Release from PI
Psych 355, Miyamoto, Spr '16

10. Forgetting in Brown-Peterson Paradigm Is Due in Part to PI
Simplified Version of Figure 6.6 (p. 157): Wicken's Study of Influence of Proactive Interference on Brown-Peterson Task
Wicken’s experiment uses the Brown-Peterson paradigm.
Experiment has 3 groups, but only two are important.
Same Slide – Emphasis Rectangle on Fruit Group
Psych 355, Miyamoto, Spr '16

11. Forgetting in Brown-Peterson Paradigm Is Due in Part to PI
Simplified Version of Figure 6.6 (p. 157): Wicken's Study of Influence of Proactive Interference on Brown-Peterson Task
Fruit Group: Every trial requires subject to remember 3 fruit.
Meat Group: Trials 1 – 3 require remembering meat words. Trial 4 requires remembering fruit words.
Results of Wicken’s Experiment
Psych 355, Miyamoto, Spr '16

12. Forgetting in Brown-Peterson Paradigm Results in Part from PI
Fruit Group
Trial 1: banana, peach, apple
Trial 2: plum, apricot, lime
Trial 3: melon, lemon, grape
Trial 4: orange, cherry, pineapple (same category)
Meat Group
Trial 1: salami, pork, chicken
Trial 2: bacon, hot doc, beef
Trial 3: hamburger, turkey, veal
Trial 4: orange, cherry, pineapple (switch category)
Same
Remember list of fruits after remembering other lists of fruits.
Remember list of fruits after remembering lists of meats.
Fruit Group
Meat Group
This figure was cut & pasted from slides distributed with Goldstein, 4th edition.
The R-code ‘\p355\rcode\release.fr.pi.fig.5.12.docm’ produces a similar graph.
% Recalled After 20 s Delay
% Recalled After 20 s Delay
Same Graph Without the Colored Boxes
Psych 355, Miyamoto, Spr '16

13. Forgetting in Brown-Peterson Paradigm Results in Part from PI
Fruit Group
Trial 1: banana, peach, apple
Trial 2: plum, apricot, lime
Trial 3: melon, lemon, grape
Trial 4: orange, cherry, pineapple (same category)
Mean Group
Trial 1: salami, pork, chicken
Trial 2: bacon, hot dog, beef
Trial 3: hamburger, turkey, veal
Trial 4: orange, cherry, pineapple (switch category)
Remember list of fruits after remembering other lists of fruits.
Remember list of fruits after remembering lists of meats.
Fruit Group
Meat Group
This figure was cut & pasted from slides distributed with Goldstein, 4th edition.
The R-code ‘\p355\rcode\release.fr.pi.fig.5.12.docm’ produces a similar graph.
% Recalled After 20 s Delay
% Recalled After 20 s Delay
Same Graph: Define “Release from PI”
Psych 355, Miyamoto, Spr '16

14. Forgetting in Brown-Peterson Paradigm Results in Part from PI
PI (Proactive Interference: Previous trials with same category (fruit or meat) interferes with STM retention on current trial.
Release from PI: Improved STM retention on trial where PI no longer influences performance.
Remember list of fruits after remembering other lists of fruits.
Remember list of fruits after remembering lists of meats.
Fruit Group
Meat Group
This figure was cut & pasted from slides distributed with Goldstein, 4th edition.
The R-code ‘\p355\rcode\release.fr.pi.fig.5.12.docm’ produces a similar graph.
% Recalled After 20 s Delay
% Recalled After 20 s Delay
Summary: What Causes Forgetting from WM/STM?
Psych 355, Miyamoto, Spr '16

15. Conclusion re Forgetting in the Brown-Peterson Paradigm
Delay in Seconds
Proactive interference is a major cause of forgetting in the Brown-Peterson paradigm.
Brown-Peterson paradigm attempts to measure decay of memory in STM, but the measurement is confounded with PI (proactive interference).
Requirements for the "Perfect" Way to Measure Decay in STM
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16. Requirements for the "Perfect" Way to Measure Decay in STM
Researcher must discover Task X such that:
Performing X does not interfere with retaining some information Z in STM, e.g., Z could be remembering the words "spoon hawk knot".
Past learning does not interfere with performance of Z, i.e., no proactive interference.
Performing X prevents rehearsal of the to-be-remembered item, e.g., prevents rehearsal of "spoon hawk knot."
In the Brown/Peterson task,
X = counting backwards by 3's
Z = remembering short lists, e.g., short lists of foods, or short lists of digits, or short lists of names, etc.
Very hard to discover a good Task X.
Bottom-Line re Forgetting in STM
Psych 355,, Miyamoto, Spr '16

17. 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., after a few seconds, if some new information interferes with the contents of WM/STM.
Why is information lost from WM/STM?
Interference – well-established cause of forgetting from WM/STM.
Decay – no one has yet proved definitively that decay does or does not occur.
Overview of WM versus STM - END
Psych 355, Miyamoto, Spr '16

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 and 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 for WM, ....
but question of how WM manipulates information is the central focus of research.
Diagram of the Atkinson/Shiffrin (Modal) Model of Memory
Psych 355, Miyamoto, Spr '16

19. Modal Model of Memory (circa 1970)
Control Processes
Input
Sensory Memory
Short-Term Memory
Long-Term Memory
Output: Speech/Actions
Diagram for the Baddeley-Hitch Working Memory Model
Psych 355, Miyamoto, Spr '16

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.
Same Slide Without the Emphasis Rectangles
Psych 355, Miyamoto, Spr '16

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.
What Justifies the Hypothesis: PL is Part of WM?
Psych 355, Miyamoto, Spr '16

22. What Justifies the Hypothesis: PL Is Part of WM?
Summary of Evidence for PL (Phonological Loop)
Phonological similarity effect: Memory span is smaller for lists of similar-sounding words than for lists of dissimilar-sounding words.
Example 1: Remember the list, D B C T P G (harder)
Example 2: Remember the list, K F Y L R Q (easier)
Word length effect: Memory span is greater for lists of short words than for lists of long words.
Articulatory suppression experiments
Neuropsychological evidence (later - not in this lecture)
Demo of the Phonological Similarity Effect
Psych 355, Miyamoto, Spr '16

23. Demo of Phonological Similarity Effect: Memory Span for Words
On each trial, you will see a sequence of words presented one after the other.
Your Task: Write down all of the words in the order in which they were presented.
For example, if you see
ORANGE  LOOSE  GRIP  TUESDAY
Write down: ORANGE, LOOSE, GRIP, TUESDAY Note that ORANGE, TUESDAY, GRIP, LOOSE is incorrect.
On each trial, make a mental note of how hard it was to do the task.
Fixation Point
Psych 355, Miyamoto, Spr '16

24. Word Span Trial with 5 Words: How Hard Is This?*
Note to Self: The following slides advance automatically on a timer, i.e., don't advance the slides manually.
Next: On Click – Display Stimulus Words on a Timer, 1 Slide per second
Psych 355, Miyamoto, Spr '16

25. Digit
EASE
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26. Digit
GONE
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27. Digit
SING
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28. Digit
TOP
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29. Digit
CRISP
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30. What Were the Words? Correct Answer: EASE, GONE, SING, TOP, CRISP
Remember how hard was that task. Next: Repeat task but with different stimulus words.
Fixation Point
Psych 355, Miyamoto, Spr '16

31. Word Span with 5 Words: How Hard is This?*
Note to Self: The following slides advance automatically on a timer, i.e., don't advance the slides manually.
On Click, Display Stimulis on Timer, 1 Slide per Second
Psych 355, Miyamoto, Spr '16

32. Digit
RAKE
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33. Digit
FATE
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34. Digit
TASTE
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35. Digit
BREAK
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36. Digit
BAIT
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37. What Were the Words? Correct Answer: RAKE, FATE, TASTE, BREAK, BAIT
Which word list was harder to remember?
List 1: The words are not similar in sound.
List 2: The words are similar in sound.
List 2 is harder to remember.
This is the phonological similarity effect.
Theoretical Analysis of the Phonological Similarity Effect
Psych 355, Miyamoto, Spr '16

38. Interpretation of Phonological Similarity Effect
Compare:
List 1: EASE GONE SING TOP CRISP MINT DOOR
List 2: RAKE FATE TASTE BREAK BAIT RATE FADE
Interpretation of Phonological Similarity Effect
Phonological similarity effect: Memory span is smaller for similar-sounding words than for dissimilar sounding words.
What does this show about working memory?
Basic Assumption of PL: One way people maintain information in STM is by rehearsing the sound of words.
Similar-sounding words are more confusable in a sound-based rehearsal. Memory span for similar-sounding words should be smaller if retention is based on rehearsal in the PL.
The predicted smaller memory span for lists of similar-sounding words is confirmed (even if the stimuli are presented visually!).
Repeat this Slide without Yellow TextBox
Psych 355, Miyamoto, Spr '15

39. Interpretation of Phonological Similarity Effect
Phonological similarity effect: Memory span is smaller for similar-sounding words than for dissimilar sounding words.
What does this show about working memory?
Basic Assumption of PL: One way that people maintain information in STM is by rehearsing the sound of words.
Similar-sounding words are more confusable in a sound-based rehearsal. Memory span for similar-sounding words should be smaller if retention is based on rehearsal in the PL.
The predicted smaller memory span for lists of similar-sounding words is confirmed (even if the stimuli are presented visually!).
Repeat: Evidence for the Existence of a Phonological Loop
Psych 355, Miyamoto, Spr '15

40. Evidence for the Hypothesis: PL Is Part of WM
Phonological similarity effect: Memory span is smaller for lists of similar-sounding words than for lists of dissimilar-sounding words.
Example 1: Remember the list, D B C T P G (harder)
Example 2: Remember the list, K F Y L R Q (easier)
Word length effect: Memory span is greater for lists of short words than for lists of long words.
Articulatory suppression experiments
Neuropsychological evidence (later - not in this lecture)
Phonological similarity effect was explained in lec04-4.p355.spr15.pptm.
Demo of the Word Length Effect
Psych 355, Miyamoto, Spr '15

41. Thursday, April 21, 2016: The Lecture Ended Here
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42. Next: Demo of Word Length Effect
Word length effect: Memory span is smaller for list of long words than for lists of short words.
"Long" means multisyllabic.
We already did some trials with short words.
Next: Memory span trial with long words.
Fixation Point
Psych 355, Miyamoto, Spr '16

43. Word Span with 5 Words: How Hard is This?*
Note to Self: The following slides advance automatically on a timer, i.e., don't advance the slides manually.
On Click, Display Stimulus on a Timer, 1 Slide per Second
Psych 355, Miyamoto, Spr '16

44. Digit
HABITUALLY
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45. Digit
NEUROTOXIN
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46. Digit
ANTICIPATION
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47. Digit
DECIDUOUS
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48. Digit
SAXOPHONE
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49. What Were the Words?
Correct Answer: HABITUALLY, NEUROTOXIN, ANTICIPATION, DECIDUOUS, SAXOPHONE
Which word list was harder to remember?
First list: Short dissimilar sounding words
Third list: Long dissimilar sounding words .
Theoretical Analysis of the Word Length Effect
Psych 355, Miyamoto, Spr '16

50. Interpretation of Word Length Effect
Word length effect: Memory span is smaller for lists of long words than for lists of short words.
What does this show about working memory?
Basic assumption of PL: One way that people maintain information in STM is by rehearsing the sound of words.
Prediction: Since longer words take longer to rehearse, it takes longer to complete the list and return to each word in the list. Therefore we are more likely to forget longer words from a list of length N than to forget shorter words from a list of length N. Thus, memory span should be smaller for longer words.
Prediction is confirmed.
Word Length Effect & Digit Span: Chinese, Welsh, & English
Psych 355, Miyamoto, Spr '16

51. Word Length Effect & Digit Span
England
Digits take longer to pronounce in English than in Chinese. Digits take longer to pronounce in Welsh than in English;
Digit span is greater for Chinese speakers than for English speakers. Digit span is greater for Welsh speakers than for Englilsh speakers.
Interpretation:
Everybody has the same basic STM capacity.
Chinese speakers can rehearse digits faster than English speakers. Therefore they can retain more digits on the average in a Digit Span task.
English speakers can rehearse digits faster than Welsh speakers. Therefore they can retain more digits on the average in a Digit Span task.
Wales
Finding for Welsh speakers was originally noticed by: Ellis, N. C.; Hennelly, R. A. (February 1980). "A bilingual word-length effect: Implications for intelligence testing and the relative ease of mental calculation in Welsh and English". British Journal of Psychology 71 (1): 43–51.
They noticed that Welsh children did worse than English speaking children on a digit span portion of the Wechsler IQ test. They investigated the reasons for this; they found that the word length effect was the probable cause.
Possible END of Lecture
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52. Possible END of Lecture
Next: Articulatory Suppression
Define Articulatory Suppression – Then Use Articulatory Suppression in Exp
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