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

Memory

The Man with the 30 Second Memory

Cog Chp 4 - short Term/Working Memory 1

http://www.liveleak.com/view?i=5a9_1261557924


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)


Short Term Memory

(STM) as a storage space.

Working Memory (WM) as a place

where mental work is done


Serial Recall test – must remember the words in the correct order

Free Recall test – may remember the words in any order.

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.



George Miller (1956) – free recall test of memory for words and numbers.

- The Magic Number 7: +/- 2


Memory Chunks – Seven Chunks of Memory can be retained in STM.

Chunking – increases capacity of STM

BATCARBOYERA - requires processing for meaning (recoding)


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


Pronunciation Time

Language Differences in digit span.

Mueller (2003) (Research Activity 4.1)

Shorter Pronunciation = Higher Digit Span


Maintenance Rehearsal: Mentally repeating items in STM

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.



Serial position effects Better Memory for1) first few words (Primacy Effect) 2) last few words in the list (Recency Effect).


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.

Duration of STM

Peterson & Peterson (1959)

Increasing the time of the secondary task (counting backwards by 3’s) reduces Memory Span.



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.


http://beta.blogger.com/post-edit.g?blogID=36132474&postID=4660008615572014267


Forgetting from Short-Term Memory: Decay or Displacement?

STM

LTM

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.



STM

LTM

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).



STM

LTM


R D Q L T H JB



STM

LTM


B R D Q L T H

J



STM

LTM

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.

B R D Q L T H

J



STM

LTM

The Probe-Digit Procedure

You are read a list of 16 digits:

(Waugh & Norman, 1965)

7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

After the last digit, you hear a tone...

TONE



STM

LTM

The Probe-Digit Procedure (Waugh & Norman, 1965)

7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

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.

TONE

This is called the “probe”.

Probe



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

The subject’s task is to recall the digit following the probe.

TONE

Between the digit, 4, and the tone, two things happen: (1) time passes, and (2) more digits are presented.

Probe

4Recall



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

Which is more important in causing forgetting, time or the additional digits?

TONE

Probe

4Recall

The decay principle implies time; the displacement principle implies digits.



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

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).

TONE

Probe

4Recall

+1+ 1 +1 +1 + 1 +1+ 1+ 1+ 1+ 1 +1 +1 = 12

Slow Presentation (Seconds)



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8More 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.

TONE

Probe

4

Fast Presentation (Seconds) 1 + 1 + 1 = 3



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8According 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.

TONE

Probe

4




STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8Waugh & 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.

TONE

Probe

4


Both decay and displacement predict an increase in recall as the probe gets closer to the tone.



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

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.

TONE

Probe

4


Results



STM

LTM


7 0 8 4 1 6 0 9 5 5 3 7 2 4 7 8

As time passes, what mainly causes forgetting from short-term memory is exposure to additional information, not the passage of time.

TONE

Probe

4


Conclusion


Participants poorer at recall when more items intervened.◙ Retroactive interference

Rate of presentation did not effect recall◙ Decay


Long-Term Memory

S Se tn os ro er y

RetrievalShort-Term Memory

Atkinson & Shiffrin (1968) Multistore Model

Rehearsal

Loss

Encoding

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.


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.



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


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

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.


http://www.youtube.com/watch?v=SAfRzrnoEqQ

Neurological EvidenceThree 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.



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.


Phonological Loop

Phonological Similarity Effect - sound based rehearsal.

Word Length Effect – not chunks, but limited time duration


Central Exec Phonological

loop

Holds acoustic information giving Central Exec longer to process it.


Visuospatial Sketch PadHolds images for further processing by centralExecutive.

Both Slave systems have limited capacity butDo not interfere with each other.

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.


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



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


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.


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.

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

Episodic Buffer

No storage capacity

Acts as a glue to integrate information within working memory


Working Memory Capacity

Information is stored briefly while processing other information.

Working Memory Capacity = Ability to combine processing and storage of Information.


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).


http://www.youtube.com/watch?v=wp4z41Jax6g


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!!


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.


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.


Prosaccade and AntisaccadeSubjects 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.


“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

Memory capacity vs.

Cognitive control capacity

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!


Documents

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