BHS 499-07Memory and Amnesia

History of Memory Research and Early

Memory Models

Three Definitions of Memory

The location where memory is stored. The physical entity that holds the

memory:• Trace

• Engram

The processes used to acquire (learn), store (encode) or retrieve information.

Metaphors for Memory

Metaphors are used because memory is hard to understand and talk about.

Different metaphors capture different aspects of memory.

The number of metaphors tells us about the complexity of memory.

Some metaphors are better than others.• Memory is NOT like a muscle – more like a key.

Metaphors 1

Recorder of experience• Wax tablet

• Record player

• Writing pad

• Tape recorder

• Video camera Organized storage

• House

• Library

• Dictionary

Metaphors 2

Interconnections• Switchboard

• Network

Jumbled Storage• Birds in an aviary

• Purse

• Junk drawer

• Garbage can

Metaphors 3

Temporal Availability• Conveyor belt

Content Addressability• Lock and key

• Tuning fork

Forgetting of Details• Leaky bucket

• Cow’s stomach

• Acid bath

Metaphors 4

Reconstruction• Rebuilding a dinosaur

Active processing• Workbench

• Computer program

The Ancients Plato (428?-347? B.C.)

• Rationalist• Dualist – mind and body are distinct• Wax tablet metaphor (can be erased, the better the

impression the more readable. Aristotle (384-322 B.C.)

• Empiricist• Laws of association

• Similarity• Contrast• Contiguity

Modern Precursors

St. Augustine (354-430)• Advanced description of memory in the Confessions

similar to modern views.

Robert Hooke (1635-1703)• Modern insights into memory, but were ignored when

he was overshadowed by Newton.

Darwin and natural selection (1809-1882)• Organism changes to exploit the environment

• Memory has developed to perform specific tasks.

Philosophy of Mind

Empiricists – extended Aristotle’s ideas• Berkeley, Locke, Mill, Hume

• Knowledge through observation

• Associationism

Rationalists – antagonists to empiricists• Descartes, Kant

• Active involvement of the mind building ideas

• Knowledge through theories (e.g., schemas)

Early Researchers

Ebbinghaus (1850-1909)• Nonsense syllables

• PIM DAG ZOL CEK

• Learning curve – massed vs spaced practice

• Forgetting curve – forgetting occurs rapidly

• Overlearning – studying after something is learned

• Savings – decreased effort needed to relearn Bartlett (1886-1969)

• How does prior knowledge influence memory

• Reconstruction is guided by schemas (concepts)

Gestalt Psychology

Gestalt movement• Kohler, Koffka, Wertheimer

• The whole is different that the sum of its parts.

• Anti-reductionistic• But did acknowledge the importance of

understanding the components of thought.

• Memory influenced by the configuration of elements and context.

• Isomorphism of mental representation

Behaviorism

Behaviorism (Pavlov, Thorndike)• Psychology should be the study of observable

behavior. • Reacting against introspection

• Associated with the term “learning”.

• Later behaviorists (like Tolman) used mental explanations and representations (maps).

Classical and operant conditioning both involve memory.

Verbal Learning

A behaviorist approach to the learning of verbal materials.• Developed from Ebbinghaus’s work.

Memorization is the “attachment of responses to stimuli”

Forgetting is the “loss of response availability”

Paired Associates Paradigm

Paired associate learning – people memorize pairs of items (BIRD-GLOVE):• A-B -- the first item is the cue and the second

is the response

• A-B C-D paradigm (two lists are learned)

• A-B A-D paradigm (two associations learned)

• A-B A-B’ paradigm (synonyms)

• A-B A-Br paradigm (recombinations – hard!)

Early Neuroscience -- Lashley

Lashley (1890-1958) Search for the engram Rats learned a maze. Lashley progressively removed larger

and larger portions of rats brains, from different locations.

Memory affected more by the amount of brain tissue removed, not the location.

Hebb

Hebb -- The Organization of Behavior (1949) Forerunner of computational neuroscience

• Mathematical modeling of brain activity

What fires together, wires together Signal reverberation within collections of cell

assemblies followed by a change in neural interconnections

The Cognitive Revolution

Thought is a valid subject for study This is the field of psychology associated

with the term “memory” Adopted the methodological rigor of the

behaviorists The computer metaphor

• hardware vs. software

Miller’s Magic Number

George Miller• The Magical Number Seven, Plus or Minus

Two (1956) – describes the capacity of short term memory

• Different for verbal items and digits

Limited capacity of memory Organization aids memory (chunking)

The Modal Model of Memory

Modal refers to sensory modality (way of receiving info from outside world).

Heuristic means “rule of thumb” – this is a way of thinking about memory but not to be taken literally.

The guiding framework for decades.

Multiple Memory Systems

Memory is not unitary but consists of several subcomponents (parts).

Tulving’s Triarchic Theory:• Episodic Autonoetic (self)

• Semantic Noetic (formal knowledge)

• Procedural Anoetic (automatic skills)

Other Classifications

Declarative vs Nondeclarative• Declarative includes episodic and semantic

memory

• Nondeclarative includes procedural memory, classical conditioning and priming

Explicit vs implicit• Explicit memory involves consciousness,

implicit does not.

Current Issues

Neurological bases for memory Impact and importance of emotion on

memory Use of multiple memory sources (fuzzy

trace theories) Embodied cognition – how our grounding

in the world influences memory