Short term memory and working memory

Question 1

What is memory?

Answer 1

Process of retaining, retrieving and using information when the information is no longer present.

Question 1

What is working memory?

Answer 1

• It’s short term memory + what we do with it.
• It is a limited capacity system for temporary storage and manipulation of information
• It’s used for complex stuff –> comprehension, learning, reasoning, etc

Question 2

What are the 3 subdivisions of memory proposed by Atkinson and Shiffrin?

Answer 2

• Sensory memory –> holds info for 200ms (visual + iconic) or few seconds (auditory/echoic)
• Short term memory –> limited capacity (5 - 7 items), lasts for 15 - 20 sec
• Long term memory –> hols huge amount of info, lasts indefinitely

Question 3

What are processes by which you pass information between stores?

Answer 3

Attention –> from SM to STM
Rehearsal –> from STM to LTM
Loss of information –> overtime if info isn’t rehearsed

Question 4

How much information can the sensory memory hold?

Answer 4

It can hold huge amounts info, perhaps everything we are seeing, but only very briefly. Most information is overwritten by following stimuli so it usually goes unnoticed.

Question 5

Describe Sperling’s classic paradigm related to sensory memory.

Answer 5

• The briefly presented participants with letter arrays
• Participants were asked to report as many letters as possible

There were 2 modes of reporting answers:
- Whole report –> Av 4.5/12 letters
- Partial report (after display has disappeared participants are asked to report the letters in one row) –> 3.3/4

As more delays are introduced performance declines rapidly. Suggests large capacity of SM, just very brief.

Question 6

What does the Short term memory include?

Answer 6

• Incoming info from sensory information
• interpretative info recalled from LTS

Question 7

How do you measure the duration of the STM?

Answer 7

You need to prevent rehearsal. Ask participants to recall info after various delay times.

• After 3s –> 80% recall
• After 18s –> 10% recall

15 - 20 sec is the classic figure for STM duration. The classic explanation for this was deacy.

Question 8

Describe Peterson and Peterson’s experiment and how it disproved decay hypothesis?

Answer 8

They found an interaction between delay and trial number.
- The difference between 3 and 18 seconds in the first trial was smaller than the the difference in average trials.
This suggests that decay theory was wrong as same decay would have been seen in all trials if it was right. Interference was seen –> interference of distracting task with info they had to remember.

Question 9

What are proactive and retroactive inferences?

Answer 9

Proactive inference is when we let previous knowledge impact the things we learn later –> more info from previous trials –> more things to interfere with new knowledge.

Retroactive inference is when new things you learn impact things you already knew.

Question 10

What is the capacity and duration of short term memory?

Answer 10

Capacity –> 5 - 8 items
Duration –> 15 - 20 sec

Question 11

What is the digit span task?

Answer 11

A task used to measure capacity of memory. Gives you a list of numbers and sees how many you can recall.

Question 12

What are the two factors that impact the remembering of an Item?

Answer 12

Chunking and complexity.

Chunking –> small units can be grouped into larger meaningful units. Ericcson et al showed that chunking improve STM of college students from 7 items to 79 items.

Complexity –> the more complex the stimulus the harder it is to remember the item. Complexity decreases STM capacity.

Question 13

What is the difference between STM and WM?

Answer 13

STM memory holds info for a brief period of time while WM does processing and manipulation of info that occurs during complex cognition

Question 14

What are the components of WM?

Answer 14

• Central executive
• Phonological loop
• Visuospatial sketchpad
• Episodic buffer?

Question 15

What is the central executive?

Answer 15

• Selectively attends to what gets from the SM to the STM and controls processes in the STM
• Suppresses other information

Question 16

What is the phonological loop?

Answer 16

• Verbal and auditory info get processes.
• Include written verbal info

Question 17

What is the phonological similarity effect?

Answer 17

• Letters or words that sound differently get more confused than letters or words that look similar.

Question 18

What is the word length effect?

Answer 18

• Larger words are harder to remember.

Question 19

What is articulatory suppression and what does it do?

Answer 19

• More evidence for phonological loop
• Repeat unrelated sounds to prevent rehearsal after the presentation of words
• Reduces memory span
• Eliminates word length effect
• Reduces phonological similarity effect for reading words

Question 20

What happens in the visuospatial sketchpad?

Answer 20

• Visual and spatial processing
• Creation of visual images in the mind after the stimulus is removed

Question 21

What did Shepard and Meltzer find in relation to mental rotation?

Answer 21

That the reaction time increases when the objects have to be rotated more.

Question 22

What is the relationship between the PL and VSSP?

Answer 22

They are partially independent –> suggests that we can process both kinds of information at once to some extent.

Ex. Brooks –> form mental image of F and trace its corners –> participants did better when they had to report corners orally rather then pointing.

Question 23

How can you study the function of the central executive?

Answer 23

1) Brain damage –> people with frontal lobe damage–> difficulty with task switching. –> Perseveration–> continue to perform inappropriate behaviors (difficulty task switching)

2) Individual differences –> Vogel et al –> compare high WM capacity with low WM capacity people. They showed stimuli and varied the # of distractors. Higher WM people did better. ERP component showed that high WM participants had less info in their WM. This suggests that high WM people are better at filtering information and not letting distractors in.

Question 24

What is the episodic buffer?

Answer 24

Store that communicated with LTM and WM. It holds information longer and has greater capacity than PL and VSSP.

Question 25

What does Cowan propose in his WM theory?

Answer 25

That attention and WM are essentially synonymous.

Question 26

What are the neurological basis of WM?

Answer 26

• Prefrontal cortex –> monkeys with no PFC have difficulty holding info.
• Individual neurons –> individual neurons in health monkeys fire depending on stimulus position and keep firing when stimulus is gone
• Functions of each slave system are done in areas associated with specific functioning. Eg., visual –> occipital lobe, auditory –> temporal lobe