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Three Stages of Memory
Sensory
Short-Term
Long-Term
Stage Model of Memory
Long-term memory
Working orShort-term
Memory
Sensory
Input
Sensory Memory
AttentionEncoding
Retrieval
Maintenance Rehearsal
Sensory Memory
• Function—holds information long enough to be processed for basic physical characteristics
• Capacity—large– can hold many items at once
• Duration—very brief retention of images– .3 sec for visual info– 2 sec for auditory info
Sensory
InputSensoryMemory
Sensory Memory
• Sensory memory forms automatically, without attention or interpretation
• Attention is needed to transfer information to the next stage
Sensory
InputSensoryMemory
Neisser's Selective Attention Test: Introduction
• At any particular moment, we focus our attention on just a few limited aspects of our experience.
• Ulric Neisser devised a test to demonstrate selective attention. A viewer sees images of three men in black shirts tossing a ball superimposed on images of three men in white shirts tossing a ball, and is instructed to press a key each time a black-shirted player passes the ball.
Selective Attention: An Example• View the Neisser’s Selective Attention Test
basketball video clip below. Count the number of passes made. (click below to start)
•Did you notice the lady walk across the room with the umbrella? No! You were too busy watching & counting the passes.
Sensory Memory or Working Memory
• Divided into two types:
iconic memory–visual information
echoic memory– auditory information
Sensory
InputSensoryMemory
Types of Sensory Memory
• Iconic memory—brief memory of an image– A quick snapshot that lasts a fraction of second.– Eidetic memory is a photographic memory that
about 5% of children possess. Fades with time.
– George Sperling studied iconic memory
• Echoic memory —brief memory of a sound – Auditory sensory memories may last longer
than visual sensory memories (several seconds)
Sperling’s Experiment• Presented matrix of letters for
1/20 of a second
• Report as many letters as possible
• Subjects recall only half of the letters
• Was this because subjects didn’t have enough time to
view entire matrix? No• How did Sperling know this?
Sperling’s Experiment• Sperling showed people can see
and recall ALL the letters momentarily
• Sounded low, medium or high tone immediately after matrix disappeared– tone signaled 1 row to report
– recall was almost perfect
High
Medium
Low
Memory for image fades after 1-3 seconds or so, making report of entire display hard to do
Short Term or Working Memory
Working orShort-term
Memory
Sensory
Input
Sensory Memory
Attention
Working or Short-Term Memory• Function - conscious processing of information
– where information is actively worked on
• Capacity - limited (holds 7 +/- 2 items)
• Duration - brief storage (about 30 seconds)
• Code - often based on sound or speech even with visual inputs
Working orShort-term
Memory
Sensory
Input
Sensory Memory
Attention
Working Memory Store
• What happens if you need to keep information in working memory longer than 30 seconds?
• To demonstrate, memorize the following phone number (presented one digit at a time)...
8 361975
Working Memory Store
• What is the number?857-9163The number lasted in your working memory longer than 30 secondsSo, how were you able to remember the number?
Maintenance Rehearsal
Working orShort-term
Memory
Sensory
Input
Sensory Memory
Attention
• Mental or verbal repetition of information Allows information to remain in working memory longer than the usual 30 seconds
Maintenance rehearsal
You’ll want to limit Interference
• When new information appears in the short-term memory and takes the place of what was already there.
Maintenance Rehearsal
• What happens if you can’t use maintenance rehearsal?• Memory decays quickly• To demonstrate, again memorize a phone number (presented one
digit at a time)– BUT, have to count backwards from 1,000 by sevens (i.e., 1000, 993,
986 … etc.)
6 490582
Working Memory Store
• What is the number?628-5094Without rehearsal, memory fades
Peterson’s STM Task• Test of memory for 3-
letter nonsense syllables
• Participants count backwards for a few seconds, then recall
• Without rehearsal, memory fades
Primacy & Recency Effect
• When given a list of items to remember we are most likely to recall…
• The first few items (Primacy Effect)
• The last few items (Recency Effect)
• We’re most likely to forget the middle items.
Ways to Improve STM: Chunking
• Grouping small bits of information into larger units of information– expands working memory load
• Which is easier to remember?– 4 8 3 7 9 2 5 1 6– 483 792 516
Long Term MemoryLTM
Long-Term Memory• Once information passes from sensory to
working memory, it can be encoded into long-term memory using maintenance or elaborative rehearsal
Long-term memory
Working orShort-term
Memory
Sensory
Input
Sensory Memory
AttentionEncoding
Retrieval
Maintenance Rehearsal
Long-Term Memory• Function—organizes and stores information
• Unlimited capacity
• Duration—thought by some to be permanent
Long-term memory
Working orShort-term
Memory
Sensory
Input
Sensory Memory
AttentionEncoding
Retrieval
Maintenance Rehearsal
Memory is a Reconstruction
• Memories are NOT perfect playbacks of past events.
• They can be influenced by new information and the way we view and organize the world (schemas).
Clive Wearing--Living Without Memory: Introduction
• Studies of malfunctions of memory have helped researchers understand how we form (encode), store, and retrieve memories. Memories are recorded successively as sensory memory (the immediate initial stage), short-term memory (or working memory), and long-term memory.
• In one extreme type of memory deficit, caused by accident or disease, a person is unable to form new memories and lives in an eternal present.
• Clive Wearing, a world-renowned choir director and musical arranger, suffered brain damage following viral encephalitis, which destroyed both temporal lobes, the entire hippocampus, and much of the left frontal lobe. He lost his ability to form new memories. He has no memory of anything beyond the last minute or two.
Clive and Deborah Wearing have one of their regular encounters, thirteen years after Clive suffered brain damage. Deborah describes Clive's repeated experience of waking up for the first time, as recorded in a diary.
Clive Wearing--Living Without Memory
Click on box or title to play.
Can also show (12:35) Segment #10 from The Mind: Psychology Teaching Modules (2nd edition).
If you’d like to view a more recent video of Clive click HERE. (5:54)
Clive Wearing--Living Without Memory: Questions
1. Why does Wearing retains many memory-related abilities, such as speech, musical ability, and ability to recognize his wife.
2. What is the role of the hippocampus (totally destroyed in Wearing) in memory formation?