LCS 11: Cognitive Science quickly you hardly catch it going? Its - - PowerPoint PPT Presentation

Pomona College

LCS 11: Cognitive Science

Memory - long and short

Jesse A. Harris March 4, 2013

Jesse A. Harris: LCS 11: Cognitive Science, Memory - long and short 1

Has it ever struck you ...that life is all memory, except for the one present moment that goes by so quickly you hardly catch it going? It’s really all memory ...except for each passing moment. Tennessee Williams. The milk train doesn’t stop here anymore.

Agenda

֠ Basic types of long term memory ֠ Working memory ֠ Schedule for unit modified Mar 6 Schacter, 2001; ch. 2-3 Mar 11 Loftus, 1997; Schacter, 2001: ch. 5 Mar 13 Bartlett, 1932; Schacter, 2001; ch. 6 Class attendance on Mar 13 optional! Discussion of writing prompt and final projects.

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Exercise

Recollection

Recall your childhood home or a building that you spent significant portions of time growing up.

• 1. What color were the walls?
• 2. How many rooms did it have?
• 3. How many windows did it have?

Introspection

Subjectively, what was the experience of recollecting like? Which experiences felt like

• 1. Long term memory?
• 2. Short term memory?

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Types of long term memory

Long Term Memory Propositional/Factual Episodic Semantic Procedural Skill

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Types of long term memory

Propositional Memory

Sometimes described as knowing that – memory representations for factual information or knowledge stored within the memory system. Episodic Knowledge about specific events, e.g., the day when you were accepted to Pomona College. Subtypes include recognition and recall memory. Semantic General facts about the world, e.g., where Pomona College is, what its students are like, etc.

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Types of long term memory

Procedural Memory

Sometimes described as knowing how – memory for how to perform actions, solve problems, etc. Skill Knowledge about how to perform a task, e.g., riding a bike; may be non-conscious.

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Long term memory

Amnesia

Memory deficit manifested by damage, disease, or trauma.

• 1. Retrograde - inability to recollect before damage
• 2. Anterograde - inability to recollect after damage

Different components likely associated with physically different locations in the brain.

Double dissociation in amnesiacs:

• 1. Poor episodic memory but intact semantic memory
• 2. Poor semantic memory but intact episodic memory

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Patient HM

◮ Severe epilepsy after bike

accident at 9

◮ Hippocampi and amygdalae

removed in late 20s

◮ Severe anterograde amnesia

afterwards unable to form new long term memories

◮ Yet, showed some retention of

procedural knowledge, as well as a few highly salient facts, such as Kennedy’s assassination.

Henry Gustav Molaison 1926–2008

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Long term memory

Getting to long term memory

In a way, long term memory is all about the past. Other memory systems deal with the present. Sensory Extremely short retention of sensation. Working Slightly longer retention of information made available to conscious processing

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Sensory memory

◮ Initial stage of memory encoding

in which sensory input is retained for very short time spans.

◮ Visual input held in memory -

trails added to sparklers; fill in visual input in films.

◮ Auditory input held in memory

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Properties of the STM system

◮ Short-term (working) memory allows us to maintain

information accessible to conscious thought for short periods of time.

◮ Necessary when executing tasks ◮ Two major questions in research in this area

• 1. Capacity: How much information does STM hold?
• 2. Duration: How long does information persist in STM?

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Working memory

Experiment

◮ Get out sheet of paper ◮ I’ll list 10 words ◮ After 30 seconds, I’ll cue you to start writing down as

many of them as you can.

◮ Try to be aware of what’s happening in your mind as you

do the task ...

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Book Vacuum Ship Justice Hearer Cloud Purple Mankind Hollow Thrill

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Wait

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Start writing!

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Working memory

◮ How many did you remember? Between 5 and 9? ◮ What was happening as you tried to maintain the words

in memory?

◮ Did you try to repeat them?

Book ...Vacuum ...Book ...Vacuum

◮ How did that work once you saw more words?

Book ...Vacuum ...Ship ...Justice ...Hearer ...Cloud

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Working memory

Recency effect

First few items probably next to be recalled. Why? First items repeated more in memory, may have improved encoding.

Primacy effect

Last few items probably were first to be recalled. Why? Items most recently held in sensory memory

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Recency effects

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Capacity

Digit span: I’ll display a row of numbers. Read the numbers, and then when they disappear, right them down in the correct

• rder.

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

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Capacity

Capacity

Information in STM is very limited: 7 ± 2 units of information (Miller, 1956)

Units of information

Number is not absolute; capacity for storage modulated by how information is packaged ...chunks

George Miller 1920-2012

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Chunking

Memory encoding

Ericsson et al (1980) found that, with over 230 hours of training over 20 months, a college student was able to steadily increase his digit span from 7 to almost 80 digits.

◮ Mnemonic associations – 3492

encoded as “3 minutes and 49 point 2 seconds, near world-record mile time” and 893 as “89 point 3, very old man”

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Chunking

Question

Did the student improve his WM capacity through practice?

Efficient retrieval structures

Efficient grouping of digits into supergroups, thereby compressing information into information chunks.

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Working memory

◮ Alan Baddeley and colleagues

developed a discrete model of WM

◮ Also explores the mechanisms

involved in transferring information between WM and LTM.

◮ Called “working memory” because

(limited) information can be maintained for long periods of time via rehearsal. Alan Baddeley

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Working memory

4 components

• 1. Central executive: independent of sensory modality;

allocates resources, like attention.

• 2. Phonological loop: short-term memory held in speech

form

• 3. Visuo-spatial sketchpad: short-term information

specialized for spatial and visual coding

• 4. Episodic buffer: temporary storage used for integration of
• ther units

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Working memory

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Working memory

Dual task logic: Can you walk and chew gum at the same time?

• 1. Tasks that use same components of the WM system will

interfere with one another

• 2. Tasks that do not use same components should not

interfere with one another

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Working memory

Robbins et al (1996): tested effects of secondary tasks on the ability of stronger and weaker chess players to select continuation moves in a chess game

• 1. Repetitive tapping (control)
• 2. Random number generation (CE)
• 3. Clockwise keypad pressing (VSS)
• 4. Repetition of “see saw” (PL)

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Working memory

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Phonological loop

◮ Two components of

phonological loop:

• 1. Phonological store: limited

capacity, holding information for only a few seconds

• 2. Articulatory rehearsal process:

mechanism that refreshes information to keep it from decaying

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Phonological loop

Phonological similarity effect

◮ Visually presented words were recalled in order ◮ Recall was about 25% worse when words in list were

phonologically similar:

• 1. FEE, HE, KNEE, . . .
• 2. BAY, HOE, ODD, . . .

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Phonological loop

Read the following words. Start writing them down after I remove them

◮ beast, bronze, wife, golf, inn, limp, dirt, star

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Phonological loop

Read the following words. Start writing them down after I remove them

◮ alcohol, property, amplifier, officer, gallery, mosquito,

• rchestra, bricklayer

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Phonological loop

◮ You probably were able to

correctly recall more words from the first list than from the second.

Word length effect

Memory for lists of words is better for short words than for long words.

◮ Why should this be? ◮ Constraints on the phonological

loop – capacity limited to about 2 seconds of material (with some additional caveats)

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Phonological loop

Dual task logic: Can you walk and chew gum at the same time?

• 1. Tasks that use same components of the WM system will

interfere with one another

• 2. Tasks that do not use same components should not

interfere with one another

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Phonological loop

Read the following words. Start writing them down after I remove them

◮ dishwasher, hummingbird, engineering, hospital,

homelessness, reasoning

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Phonological loop

Read the following words while repeating “the, the, the, the, ...” out loud. Start writing them down after I remove them

◮ automobile, apartment, basketball, mathematics,

gymnasium, Catholicism

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Phonological loop

◮ Again, you probably were able

to correctly recall more words from the first list than from the second.

Articulatory suppression effect

Remembering word list becomes harder when the phonological loop is engaged.

◮ It also eliminates the word

length effect

◮ Why do you think this is?

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Phonological loop

◮ Word length effect: key factor is not number of syllables,

but the time it typically takes to say them.

◮ Baddeley et al (1975) observed worse performance on

recall of two syllable words with long vowels like harpoon and voodoo than for two syllable words with short vowels like bishop and wiggle.

◮ Conclusion? Rehearsal within phonological loop has a

limited duration: the greater the duration of the word, the more space it takes up in the phonological loop, and the more likely it is to be dropped.

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Patient CW

◮ Well known musicologist and

conductor

◮ Disease attacked his central

nervous system

◮ Severe limitations on short term

memory to 10 – 30 seconds

◮ Keeps a diary containing entries

• f continuous awakening

◮ Able to acquire new skill, but

doesn’t remember doing it

http://www.youtube.com/watch?v=5ObnErfTblY

Clive Wearing

• b. 1938

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