overview of memory atkinson-shiffrin model sensory signals sensory memory short-term memory...

Overview of Memory

• Atkinson-Shiffrin Model

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

“Types” of Memory

• Sensory Memory– brief ( < 1 second)– preattentive / parallel processing (very

large capacity)

Sensory Memory

Capacity

• Describe a simple experiment that could measure the capacity of “memory”

Capacity

• Describe a simple experiment that could measure the capacity of “memory”

• Briefly present some letters or digits and then ask the subject to report them– Called “whole report”

Capacity

F S F EG S A UT O C G

Capacity

“Recall as many letters as you can”

Capacity

• George Sperling - Systematic investigation of memory capacity

– Result: subjects accurately recall 3 or 4 items

– What can you conclude from this result?

Capacity

• What if subjects forget as they are recalling?

Capacity

• What if subjects forget as they are recalling?

• How could you modify the experiment to measure the instantaneous capacity, before any forgetting can occur?

Capacity

• Partial Report - briefly present letters or digits and ask subject to report only some of them

“Report the letters in the row indicated by the arrow”

Capacity

U E S BO D W AI B V S

Capacity

Capacity

Which Letters?

Capacity

• Partial Report

• Result: subjects can recall any 3 or 4 letters that are indicated by the arrow !

Capacity

• Partial Report

• Result: subjects can recall any 3 or 4 letters that are indicated by the arrow !

• What does this mean about the capacity of memory?

Capacity

• There is some part of the perception system that stores huge amounts of information…

Duration

• But for how long? How would you design an experiment to measure the duration of this high-capacity memory system?

Duration

• But for how long? How would you design an experiment to measure the duration of this high-capacity memory system?

• Vary the onset of the probe

Duration

• Partial Report

Probe Delay

# of letterspotentially recalled

500 ms0 ms never

0

4

10

Duration

• Partial Report

Delay

# of letters potentiallyrecalled

Interpretation:1. Information dwells in a brief storage “buffer”2. duration of storage lasts about 1/2 of one second

500 ms0 ms never

0

4

10

Iconic Memory

• a brief storage of “raw data” in the visual system

Echoic Memory

• Auditory information is stored in a similar sensory “buffer”– Echoic memory seems to last for several

seconds

Properties of Sensory Memory

1. Brief (iconic ~500ms; echoic ~2 seconds)

Properties of Sensory Memory

1. Brief (iconic ~500ms; echoic ~2 seconds)

2. unlimited capacity

Properties of Sensory Memory

1. Brief (iconic ~500ms; echoic ~2 seconds)

2. unlimited capacity

3. pre-attentive

Next Time:

• Short-term memory