psyco 350 lec #2 – slide 1 lecture 2 – psyco 350, a1 winter, 2011 n. r. brown

Psyco 350 Lec #2 – Slide 1

Lecture 2 – Psyco 350, A1Winter, 2011

N. R. Brown


Outline

• A Little History• Information Processing & the Modal Model• Memory Systems• Aspects of Modal Model:

– STM vs LTM: Serial Position Curve

– Properties of STM• Capacity: Span Task• Duration/Forgetting: Brown Peterson Task• Retrieval: Sternberg Task


A Very Little Bit of History


Hermann Ebbinghaus (1850-1909)

• Father of Memory Research

• Memory stripped of meaning

• Inventor of the nonsense syllable (DAX, FOZ, KIR)

• Discoverer of:– Learning curve

– Forgetting function


Fredrick Bartlett (1850-1909)

• Impact of prior knowledge and meaning on memory.

• Most important ideas:– reconstruction

– schemata


Verbal Learning

• Emerged from Behaviorism

• Focus:– relationship between external variables and

human memory performance

– forgetting and theories of forgetting

• Approach: – Rigorously conducted, list learning (often paired

associate) experiments


Historical PrecedenceEbbinghaus

Behaviorism

Bartlett

Verbal Learning

Information Processing

Cog Psych

Contemporary Memory

Research


And Now …

Cognitive Research

Memory Research



• Core metaphor:

human mind as serial computer

• To understand/describe computer behavior, specify:– hardware

– software

– available data



To understand/describe human behavior, specify:

• the cognitive architecture (hardware)– identify components & their general function:

– characterize components in terms of:• capacity• speed• accuracy

• a cognitive task analysis (software & data)



Cognitive Task Analysis (software & data):

• What are the mental operations required to perform a task?

• How are the operations sequenced?• What information is involved in task?• How is the information accessed?• How is it represented?• How is it altered during the processing?


A Simple Computer Architecture

• Input devices/registers

• Active memory and processing

• Inactive (but accessible) memory


Modal Model of Memory

• The standard model of memory

• Atkinson & Shiffrin (1968)

• Four components– Sensory registers

– Short-term memory

– Long-term memory

– Control processes


Modal Model of Memory


Modal Model: Component Functions

1. Sensory stores:function: buffers sensory input for selection and identification

2. Short-term Memory

function: temporal storage during processing

3. Long-term Memory

function: store declarative & procedural knowledge

declarative -- knowing that

procedural -- knowing how

4. Attention

function: Selection and transfer from sensory stores

Maintenance of information in STM

Selection and scheduling of tasks


Multiple (Long-term) Memory Systems

• Long-term memory involves several sub-components

• Different memory systems for different types of information


Multiple Memory Systems

• Memory– Declarative Memory (explicit memory)

• Semantic memory –“permanent,” decontextualized knowledge

• Episodic memory–“forgettable” event memories

– Nondeclarative memory (implicit memory)• Procedural memory• Classical conditioning• Priming


Memory as Everything – A Simple Demonstration• (read &) store 1st #: [84] blue = WM• (read &) store 2nd #: [57]• Retrieve-execute: [2-digit addition strategy] red =

procedural• retrieve top ones digit: [4] memory • retrieve bottom ones digit: [7]• retrieve addition fact: [4+7=11] green = semantic• store ones sum: [1] memory• retrieve-execute: [carry operation]

– retrieve top tens digit: [8]– retrieve addition fact: [8+1=9]– store new top tens digit: [9]

• retrieve top tens digit [9]• retrieve bottom tens digit: [5]• retrieve addition fact: [9+5=14]• store tens sum [14_]• Retrieve, combine sums[14; 1 141]• State answer: “141”


Modal Model: Evidence STM – LTM Distinction

• Assumption: – dual stores – STM & LTM:

• small amount of info held briefly in STM• rehearsal enables and is required for transfer

from STM to LTM

• Support: serial-position-curve phenomena


Free Recall & the Serial Position Curve

Memory Tests

Recognition

Uncued

Serial

Cued

Recall

FREE


Free Recall Task

List #1 – 15 words

Instructions:

There are 15 words on this list.

When I say to, please write down as many of these words as you can.


Free Recall Task

List #2 – 15 words; 20 s delay

Instructions:

There are 15 words on this list.

When I say to, please write down as many of these words as you can.


Free Recall & the Serial Position Curve

• Free recall:– uncued recall of studied items

– order of output unconstrained

• Manipulate a variety of:– Encoding factors (e.g. presentation rate)

– Storage factors (e.g., delay)

• Dependent variable:– % recalled as a function of serial position


Serial Position Curve

• Primacy: Good recall for 1st few items • Recency: Good recall for last few items on list


Modal Account of the Serial Position Curve

• Recency Effect produced by read-out from STM

• Primacy & “pre-recency” reflect information retrieved from LTM

• “Transfer” from STM to LTM caused by rehearsal.

• Implications: – Primacy & Prerecency: w/ rehearsal

– Recency: unaffected by rehearsal


Rundus (1971): Rehearsal & the Serial Position Curve

• Materials– 20-word list

– presentation rate: 5 s/word

• Task(s): – During study – overt rehearsal

– During test – free recall


Rundus: Rehersal Protocols


Relation between Rehearsal & Recall

• Analysis:– # rehearsals for each

word (position)

– % recall for each word (position)

• Results:– “For a given amount of

rehearsal, items from the initial serial positions are no better recalled than items from the middle of the list” – Rundus, 1971, p. 66


Relation between Study-time (Rehearsal) & Recall

• Glanzer & Cunitz (1966)

• manipulate study-time.

• Assume: study time & rehearsal related

• Results:– Primacy & Prerecency:

w/ study time

– Recency: unaffected by rehearsal

styd


Relation between Filled Delay & Recall

• Glanzer & Cunitz (1966)

• Manipulate retention interval.

• Assume filled delay replaces contents of STM

• Results:– Primacy & Prerecency:

un affected by delay

– Recency as delay

styd


Amnesia & Serial Position• Baddeley & Warrington

(1970)• H.M. – removal temporal

lobe and hippocampus• Clobbered Explicit

memory.• Yet – on immediate test,

recency intact

styd


Dissociation: Evidence for Dual Store• Dissociation – when “a single variable has different affects on

two or more measures.”• Evidence for separate stores, processes, or representation.• Many variables have dissociative effect on the prerecency &

recency portion of serial position curve.

Prerecency Recency

Study time =

Post-list distraction = Ant. Amnesia =

List Length =

Word Frequency

psyco 350 lec #2 – slide 1 lecture 2 – psyco 350, a1 winter, 2011 n. r. brown

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