1. Cog Chp 4 - short Term/Working Memory
The Man with the 30 Second Memory
Cog Chp 4 - short Term/Working Memory

2. Short Term Working Memory (STWM)
A.K.A. – Primary memory, Immediate Memory, Short-term store, Temporary Memory, Supervisory-Attention System (SAS) and Working Memory (WM)
Cog Chp 4 - short Term/Working Memory

3. Cog Chp 4 - short Term/Working Memory
Short Term Memory
(STM) as a storage space.
Working Memory (WM) as a place where mental work is done
Cog Chp 4 - short Term/Working Memory

4. Cog Chp 4 - short Term/Working Memory
Serial Recall test – must remember the words in the correct order
Free Recall test – may remember the words in any order.
Cog Chp 4 - short Term/Working Memory

5. Capacity of Short Term Memory
John Jacobs (1887) used the Memory span test with every letter in the alphabet and numbers apart from “w” and “7” because they had two syllables. He found out that people find it easier to recall numbers rather than letters. The average span for letters was 7.3 and for numbers it was 9.3.
Cog Chp 4 - short Term/Working Memory

6. Cog Chp 4 - short Term/Working Memory
George Miller (1956) – free recall test of memory for words and numbers.
- The Magic Number 7: +/- 2
Cog Chp 4 - short Term/Working Memory

7. Cog Chp 4 - short Term/Working Memory
Memory Chunks – Seven Chunks of Memory can be retained in STM.
Chunking – increases capacity of STM
BATCARBOYERA
- requires processing for meaning (recoding)
Cog Chp 4 - short Term/Working Memory

8. Cog Chp 4 - short Term/Working Memory
Herb Simon (1974) - Larger Chunks reduce memory span.
Chunk Size
Memory Span
Unrelated words
6 or 7
Two Word Phrases 4
Eight Word Phrases 3
Cog Chp 4 - short Term/Working Memory

9. Cog Chp 4 - short Term/Working Memory
Pronunciation Time
Language Differences in digit span.
Mueller (2003) (Research Activity 4.1)
Shorter Pronunciation = Higher Digit Span
Cog Chp 4 - short Term/Working Memory

10. Maintenance Rehearsal: Mentally repeating items in STM
Cog Chp 4 - short Term/Working Memory

11. Cog Chp 4 - short Term/Working Memory
Cowan et al. (2005) Running Memory Task Method to control for rehearsal and Transfer to Long Term Memory. Presented unpredictable number of digits very rapidly. The Magical Mystery Four! - when rehearsal is not allowed, Memory Span drops to 4.
Cog Chp 4 - short Term/Working Memory

12. Cog Chp 4 - short Term/Working Memory
Serial position effects
Better Memory for
1) first few words (Primacy Effect)
2) last few words in the list (Recency Effect).
Cog Chp 4 - short Term/Working Memory

13. Cog Chp 4 - short Term/Working Memory
Evidence
Present words too quickly to allow rehearsed - Primacy effect disappears.
When rehearsal after presentation is eliminated (e.g., Brown- Peterson task) Recency Effect Disappears.
Primacy – early words rehearsed more -- moved to LTM.
Recency - last words still in STM -- recovered directly.
Cog Chp 4 - short Term/Working Memory

14. Cog Chp 4 - short Term/Working Memory
Duration of STM Peterson & Peterson (1959) Increasing the time of the secondary task (counting backwards by 3’s) reduces Memory Span.
Cog Chp 4 - short Term/Working Memory

15. Why is information lost from STWM?
Brown-Peterson Studies
Distracter task (e.g., count backwards)
- eliminates rehearsal
- items are lost from STM
- recency effect disappears
If not attended to at least every 20 secs the memory trace DECAYS and items lost from STM.
Cog Chp 4 - short Term/Working Memory

16. Cog Chp 4 - short Term/Working Memory

17. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
After information enters STM, a copy may or may not be sent to LTM. Soon, however, that information will disappear from STM.
Two processes could cause information to disappear from STM:
Decay and Displacement.
Cog Chp 4 - short Term/Working Memory

18. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
Decay: information that is not rehearsed disappears as time passes.
Displacement: information being held in STM is pushed out by newly arriving information.
Displacement is most likely to occur when the capacity limit of STM has been reached (about 7 units of information).
Cog Chp 4 - short Term/Working Memory

19. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement? B R D Q L T H J
Displacement is most likely to occur when the capacity limit of STM has been reached (about 7 units of information).
Cog Chp 4 - short Term/Working Memory

20. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement? B R D Q L T H J
Displacement is most likely to occur when the capacity limit of STM has been reached (about 7 units of information).
Cog Chp 4 - short Term/Working Memory

21. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement? B R D Q L T H
The original version of the Stage model emphasized decay as the main cause of forgetting in STM. Their later version emphasized displacement. Here is a study that compared decay to displacement and showed a much greater effect of displacement. J
Cog Chp 4 - short Term/Working Memory

22. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
You are read a list of 16 digits:
TONE
After the last digit, you hear a tone...
Cog Chp 4 - short Term/Working Memory

23. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
TONE
The tone is a signal to recall one of the digits. The last digit before the tone (8) occurs only once at an earlier point in the list.
This is called the “probe”.
Cog Chp 4 - short Term/Working Memory

24. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe 4
TONE
Recall
The subject’s task is to recall the digit following the probe.
Between the digit, 4, and the tone, two things happen: (1) time passes, and (2) more digits are presented.
Cog Chp 4 - short Term/Working Memory

25. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe 4
TONE
Recall
Which is more important in causing forgetting, time or the additional digits?
The decay principle implies time; the displacement principle implies digits.
Cog Chp 4 - short Term/Working Memory

26. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Slow Presentation (Seconds)
= 12 4
TONE
Recall
Time and digits are correlated (confounded). To separate them, Waugh & Norman used two rates of presentation: slow (1 digit per second) and fast (4 digits per second).
Cog Chp 4 - short Term/Working Memory

27. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Fast Presentation (Seconds)
= 3 4
TONE
More time passes between the digit and the tone with slow presentation (12 seconds) than with fast presentation (3 seconds). According to the decay principle, the chances of recalling the digit should be lower with slow than with fast presentation.
Cog Chp 4 - short Term/Working Memory

28. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Fast Presentation (Seconds)
= 3 4
TONE
According to the displacement principle, the chances of recalling the digit should be the same with fast and slow presentation because the number of digits before the tone is the same in both conditions.
Cog Chp 4 - short Term/Working Memory

29. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Fast Presentation (Seconds)
= 3 4
TONE
Waugh & Norman made this comparison with the probe digit in each of the following positions: 3 (shown here), 5, 7, 9, 10, 12, 13, or 14.
Both decay and displacement predict an increase in recall as the probe gets closer to the tone.
Cog Chp 4 - short Term/Working Memory

30. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Fast Presentation (Seconds)
= 3 4
TONE
Results
There was slightly (but not significantly) higher recall with fast than with slow presentation when the probe was near the beginning of the list. Recall dropped sharply as the probe was moved from the end toward the beginning.
Cog Chp 4 - short Term/Working Memory

31. Forgetting from Short-Term Memory: Decay or Displacement?
STM
LTM
Forgetting from Short-Term Memory: Decay or Displacement?
The Probe-Digit Procedure
(Waugh & Norman, 1965)
Probe
Fast Presentation (Seconds)
= 3 4
TONE
Conclusion
As time passes, what mainly causes forgetting from short-term memory is exposure to additional information, not the passage of time.
Cog Chp 4 - short Term/Working Memory

32. Cog Chp 4 - short Term/Working Memory
Participants poorer at recall when more items intervened.
◙ Retroactive interference
Rate of presentation did not effect recall
◙ Decay
Cog Chp 4 - short Term/Working Memory

33. Cog Chp 4 - short Term/Working Memory
Atkinson & Shiffrin (1968) Multistore Model
S S
e t
n o
s r
o e r y
Retrieval
Short-Term Memory
Long-Term Memory
Encoding
Rehearsal
Loss
Cog Chp 4 - short Term/Working Memory

34. Short Term vs. Long-Term Memory (LTM)
Capacity and Duration Difference Double Dissociation? Milner (1966) patient H.M normally working short-term memory with an impaired long term one. Shallice & Warrington (1970) patient K.F. unimpaired long-term memory performance while a severe impairment in short-term memory.
Cog Chp 4 - short Term/Working Memory

35. Unitary-Store Approach
STM is just that fraction of LTM activated at any given moment. Ruchin (1999) – EPRs during serial recall test Compared Pseudowords to real works More activity with words than with pseudowords People process semantic information (not just sound) when words are presented.
Cog Chp 4 - short Term/Working Memory

36. Cog Chp 4 - short Term/Working Memory
Working Memory (WM)
(Baddley & Hitch)
Place where mental work is done.
- activates information from LTM into WM and from WM to LTM.
Consists of two levels of processors
Central Executive
Helper Systems – modality specific memory stores
Cog Chp 4 - short Term/Working Memory

38. Cog Chp 4 - short Term/Working Memory
Central Executive (Boss)
- Directs the flow of Information
- limited capacity
- role is of attention rather than memory
- activation of info from LTM
Control Processes
- rehearsal
- coding for meaning
- integration of information
- decision making
Cog Chp 4 - short Term/Working Memory

39. Cog Chp 4 - short Term/Working Memory
Central Executive
Resembles an attention System
No storage ability
Frontal Lobes Thought to play a large role.
Dysexecutive syndrome is a neurological impairment of executive function, where patients have trouble with complex thinking and reasoning tasks.
Cog Chp 4 - short Term/Working Memory

40. Neurological Evidence
Three major executive processes based on different parts of the Frontal Lobe. Task Setting – simple planning Monitoring – checking that the task is being performed correctly. Energization – sustained attention or concentration.
Cog Chp 4 - short Term/Working Memory

41. Cog Chp 4 - short Term/Working Memory
Storage and Temporary Maintenance of information
Phonological Loop
Two structures
1. Phonological buffer
- holds verbal info for a few minutes
2. Subvocal rehearsal loop
(- everything we said about STM.)
Though to be important for verbal processing.
Cog Chp 4 - short Term/Working Memory

42. Cog Chp 4 - short Term/Working Memory
Phonological Loop
Phonological Similarity Effect - sound based rehearsal.
Word Length Effect – not chunks, but limited time duration
Cog Chp 4 - short Term/Working Memory

43. Cog Chp 4 - short Term/Working Memory
Holds acoustic information giving Central Exec longer to process it.
Central
Exec
Phonological
loop
Cog Chp 4 - short Term/Working Memory

44. Cog Chp 4 - short Term/Working Memory
Visuospatial Sketch Pad
Holds images for further processing by central
Executive.
Both Slave systems have limited capacity but
Do not interfere with each other.
Cog Chp 4 - short Term/Working Memory

45. Visuo-Spatial Sketchpad
Capacity – About 4 Items Vogel et al. (2001) Presented displays of between 3 to 12 objects. 90ms later followed by either identical display or identical with one object changed. Performance good up to four objects then begins to decline.
Cog Chp 4 - short Term/Working Memory

46. Are Visuo and Spatial Stores?
Visual task (is it the same object) Spatial task (is it the same location) Activated different areas of the Cortex Gender Differences
Cog Chp 4 - short Term/Working Memory

47. Cog Chp 4 - short Term/Working Memory
Episodic Buffer – storage system that can hold information from the phonological loop and visuo-spatial sketchpad.
General storage system for combining and integrating information from other components and from long-term memory.
- Limited capacity
Cog Chp 4 - short Term/Working Memory

48. Cog Chp 4 - short Term/Working Memory
Robbins et al. (1996)
Chess players (skilled and novice) had to select moves from various chess positions.
Secondary Tasks
One group of participants engaged their central executive by using their attention to generate random letter sequences while trying to memorize the positions of pieces.
Cog Chp 4 - short Term/Working Memory

49. Cog Chp 4 - short Term/Working Memory
 Articulatory suppression task e.g. saying ‘see-saw” while trying to remember the positions.
Visuo-spatial sketchpad suppression task – pressing keys on a keyboard in a clockwise fashion.
After 10 seconds their memory was tested.
Participants in the articulatory suppression group performed well.
Cog Chp 4 - short Term/Working Memory

50. Figure 4.4 Effects of secondary tasks on quality of chess-move selection in stronger and weaker players. Adapted from Robbins et al. (1996).

51. Cog Chp 4 - short Term/Working Memory
Episodic Buffer
No storage capacity Acts as a glue to integrate information within working memory
Cog Chp 4 - short Term/Working Memory

52. Working Memory Capacity
Information is stored briefly while processing other information. Working Memory Capacity = Ability to combine processing and storage of Information.
Cog Chp 4 - short Term/Working Memory

53. Cog Chp 4 - short Term/Working Memory
Measuring WM Capacity
Reading Span – Largest number of sentences from which an individual can recall the final words 50% of the time. Operation Span (demo at 3:17) Dual task (math and memory).
Cog Chp 4 - short Term/Working Memory

54. Cog Chp 4 - short Term/Working Memory
Cog Chp 4 - short Term/Working Memory

55. Cog Chp 4 - short Term/Working Memory
WM Capacity is more strongly related to Fluid than to Crystalized Intelligence! This is a correlation!! WM capacity could be causing higher IQ. IQ could be causing higher WM Capacity. Both could be related to come third factor!!
Cog Chp 4 - short Term/Working Memory

56. Cog Chp 4 - short Term/Working Memory
Attentional Control
Refers to individuals' capacity to choose what they pay attention to and what they ignore. e.g., Distractibility – The correlation between WM Capacity and performance in a visual search task is only found when distractors are present.
Cog Chp 4 - short Term/Working Memory

57. Cog Chp 4 - short Term/Working Memory
e.g., Lapses in attention (vigilance tasks) High WM capacity showed fewer lapses in attention. Allocation of Attention. Low WM – inflexible, like spotlight High WM – more flexible, divided attention.
Cog Chp 4 - short Term/Working Memory

58. Prosaccade and Antisaccade
Subjects view a fixation point and a visual target is presented. Subjects are instructed to make a saccade away from the target (antisaccade) or to the target (prosaccade). Prosaccade – no relation to WM capacity Antisaccade – High WM were better.
Cog Chp 4 - short Term/Working Memory

59. Cognitive control capacity
Memory capacity
vs.
Cognitive control capacity
“Greater working memory capacity does not mean that more items can be maintained as active, but this is a result of greater ability to control attention,…ability to use attention to avoid distraction.”
-Engle RW

60. The Answer is not that simple!
Dual-Component Model – Attention Control is Important but so is LTM. Multiple Regression Studies Fluid Intelligence related to LTM, Attentional Control and Working Memory Capacity!
Cog Chp 4 - short Term/Working Memory