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Overview of Memory. Atkinson-Shiffrin Model. RETRIEVAL. ATTENTION. Sensory Memory. Short-Term Memory. Long-Term Memory. Sensory Signals. REHEARSAL. “Types” of Memory. Sensory Memory brief ( < 1 second) preattentive / parallel processing (very large capacity). Sensory Memory. Capacity.
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Overview of Memory • Atkinson-Shiffrin Model RETRIEVAL ATTENTION Sensory Memory Short-Term Memory Long-Term Memory Sensory Signals REHEARSAL
“Types” of Memory • Sensory Memory • brief ( < 1 second) • preattentive / parallel processing (very large capacity)
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 E G S A U T 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 B O D W A I B V S
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 10 # of letters potentially recalled 4 0 0 ms 500 ms never Probe Delay
Duration • Partial Report 10 # of letters potentially recalled 4 0 0 ms 500 ms never Delay Interpretation: Information dwells in a brief storage “buffer” duration of storage lasts about 1/2 of one second
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 • Brief (iconic ~500ms; echoic ~2 seconds)
Properties of Sensory Memory • Brief (iconic ~500ms; echoic ~2 seconds) • unlimited capacity
Properties of Sensory Memory • Brief (iconic ~500ms; echoic ~2 seconds) • unlimited capacity • pre-attentive
Next Time: • Short-term memory