EXP6939HUMAN MEMORY

• Focus and structure of course

• A brief personal history

• Some themes in the study of memory

• Prescientific perspectives on memory

• A Science of memory: methods and measures

• Assignments for next week

THEMES IN THE STUDY OF HUMAN MEMORY(Baddeley, Ch. 1)

• How should memory be described?– Phenomenological– Information processing– Biological

• What does it include? Is memory singular or plural?– Episodic versus semantic– Declarative versus procedural– Short term versus long-term– Implicit versus explicit

• How are lab studies related to “everyday memory?”– The issue ecological validity– Areas of “applied memory research”

SCHACTER’S THEMES:MEMORY’S “FRAGILE POWER”

• Memory is powerful– Who we are is what we remember– Its role in everyday tasks– Normally functions in the background

• Memory is fragile– Omissions, distortions and constructions

in everyday life– These may be adaptive– It’s vulnerable to a host of impairments

• Memory is not singular– Differences based on duration, content,

accessibility– Different processes can be selectively

impaired– And tied to different brain regions– The search for “dissociations”

MEMORY’S FRAGILE POWER(cont’d)

• Remembering is an act of synthesis– Combining fragments of the past with

present state and goals– Memory as an attribution– Different subjective states of memory

(e.g., remember or know?)

• Memory has both automatic and effortful aspects– Most remembering as a mixture of the

two– Different brain regions involved in

automatic and strategic aspects of memory?

MEMORY THROUGH THE AGESPrescientific perspectives

Ancient gods for memory

Greek and Roman philosophy

• Plato (427-347 BC)– Innate concepts and memories– Metaphoric mechanisms for

• Encoding (a scribe; misencoding)• Storage (wax tablet; distortable)• Retrieval (aviary; retrieval failure)

• Aristotle (384-322 BC)– Retention & knowing versus

“recollection”– Nature of representation– Individal differences in memory– Laws of association in recall

• Contiguity, similarity, contrast– Automatic and effortful retrieval– Potential for false memory and

source amnesia

Aristotle’s On Memory and Reminiscence (c. 350 bc)

• Memory vs. recollection– Memory is necessary, not sufficient for

recollection– Recollection a form of inference

(attribution?) placing ourselves in a certain time and space

– Some phrases sound like implicit/explicit, some availability/accessibility

• Recollection and association– Retrieval as “movement” between related

memories– Associative “laws” (contiguity, similarity)– Automatic cuing vs. effortful search

• Interesting comments about:– Rehearsal and practice– Concrete vs. abstract “codes”– Role of the “substrate” (hard/soft walls)– Recollection may be in error– Arousal hurts memory– Dwarfs have lousy memory

• Cicero (106-43 BC)– Practical aspects of memory– “method of loci” for remembering order

• Augustine (354-430 AD)– Sensory vs. ‘intellectual” memories– Active nature of remembering– Potential for “false memories”– Importance of emotion in memory

“Aristotle was the sort of universal Genius who makes three-paragraph summaries about him seem peculiarly lightheaded and perverse.” [Murphy &Kovach, Historical Introduction to ModernPsychology]

The Renaissance:Empirical observation

• Juan Luis Vives (1492-1540)– Spanish humanist/empiricist– “Three Books on the Soul of Life” (1538)– Importance of rehearsal for retention– Utility of “memory exercise” and practice– Three sources of forgetting

• “image’ is erased or destroyed• Smeared or fragmented• Or “escapes our search”

• Francis Bacon (1561-1626)– British philosopher/humanist– Describes the “inductive method”– Basic skills of memory, fancy, reason– Mnemonic strategies

• Visual imagery• Study prior to sleeping• Varied encoding• Selective memory search

(“prenotion”)

British Empiricism and Continental Nativism

• Thomas Hobbes (1588-1679)– Memory as “decaying sensations”– Knowledge results from experience– Founds British empiricist tradition

(Locke, Hume, Hartley, Mill)

• Rene Descartes (1596-1650)– Mental laws vs. physical (dualism)– Importance of innate concepts and

processes

A SCIENCE OF MEMORY

• Herman Ebbinghaus (1850-1909)– Prussian philosopher– Steeped in British empricist approach– “Uber das Gedachtnis” (1885)– First experimental work on memory– Introduces basic controlled methods– Describes basic memory phenomena

• Learning and forgetting functions• List-length effects and STM span• Serial position and spacing effects• Remote and backward associations• Importance of meaningfulness and

organization– Contrasts effortful and automatic

retrieval– Contrasts explicit and implicit

memory

DESIGNING A MEMORY EXPERIMENT

• Manipulation versus control• Whose memory will we study?

– Effects of age, gender, disorders, expertise

• What state are they in?– Arousal, mood, motivation

• What is the object of memory?– Verbal or nonverbal material– Simple or complex structure– Learned in the lab or elsewhere

• What are the conditions of presentation?– Visual, auditory or other modality– Number of presentations– Sequence of presentations– Time between presentations– Context of presentations

• What will they do with the material?– Intentional or incidental instructions– Special encoding tasks

• Who gets what conditions?– Between-group or within-subject

• How long is the retention interval?– Immediate (STM, seconds to tens of sec)– Recent (LTM, minutes to hours)– Remote (LTM, months to decades)

• What is the memory task?– Explicit tests of memory

• Free or cued recall• Recognition

– Implicit tests of memory• Repetition priming, fragment completion

• What attribute(s) do we test?– Identity, frequency, position, sequencing

of items

MEASURING MEMORY:THE DEPENDENT VARIABLES

• Performance measures– Accuracy, speed of response

• Potential for speed-accuracy trade-offs

Attention Condition

FullDivided

RT(ms) 620 540 errors (%) 4 6

– Types of errors• omission, commission, distortions in recall

• Hits and false alarms in recognition

Proportion “old” wordsHigh Low

Hits .80 .40False Alarms .30 .05

d’ 1.37 1.39

• Subjective judgments– Confidence

• Is confidence correlated with accuracy?– Qualitative judgments (remember-know)

• Physiological markers– Measures of CNS: Blood flow

• Positron emission tomography (PET)• Magnetic resonance imaging (MRI, fMRI)

– Measures of CNS: electromagnetic activity

• Electroencephalography (EEG, ERP)• Magentoencephaolography (MEG)• Optical imaging (EROS)

– Measures of ANS activity• Galvanic skin responses (GSR)• Muscular activity (EMG)• Heart, respiration rate

AN OBSESSION WITH MEMORY

• Marcel Proust’s In Search of Lost Time– 1908-1922; 8 volumes, 3,000 pages– Recollections, and meditations

• “I understood that all the material of a literary work was in my past life, I understood that I had acquired it in the midst of frivolous amusements, in idleness, in tenderness and in pain, stored up by me without my divining its destination or even its survival, as the seed has in reserve all the ingredients which will nourish the plant.”

TWO CASES OF AMNESIA

• GR (from Schacter 96)– 67-yr old Italian poet & artist– Stroke damages left thalamus– Almost complete amnesia for “episodic

past” (retrograde amnesia)– Little ability to remember new events

(anterograde amnesia)– Near-full recovery a year later

• Sheila (from Campbell & Conway 95)– 32-yr old school teacher– Severe herpes encephalitis– Damage to temporal lobes, right frontal

lobes– Mild RA, profound AA (the classic

“amnestic syndome”– Little hope for recovery

A RECENT CASE OF “MEMORY THEFT”

• Binjamin Wilomirski’s “Fragments”– 1995 book by Holocaust survivor– 1999: Expose by Ganzfried– Was it fraud? Or misconstruction?

REMEMBERING VERSUS KNOWING

• The remember-know distinction (Tulving, 85)– Importance of contextual and sensory

detail of episode

• Dissociations based on– Divided attention at study selectively

reduces “remember” judgments (Gardiner & Parkin, 1995)

– Elaborative encoding at study selectively enhances “remember” judgments, and

– Study of pictures versus words selectively enhances “remember” judgments (Rajaram, 1993)