COGNITIVE SCIENCE 17

Can You Remember My Name?

Part 1 Jaime A. Pineda, Ph.D.

The Persistence of MemoryDali, 1931

Nature of Learning(synaptic plasticity)

• Experiences produce changes in the brain (learning)– Perceptual: the ability to identify and categorize objects through

our senses (knowing about things); takes place in sensory systems– Motor: the ability to identify and categorize things through our

motor systems (knowing what to do)– Stimulus-response: establishing an association between a

stimulus perception and a motor response • Classical and instrumental conditioning (Hebbian rules/LTP and LTD)

– Relational: the relationships among individual stimuli• Spatial • Episodic• Observational

Nature of Memory

– Changes in the brain as a result of experiences are retained for a period of time (memories)

– How and where are memories stored?• Karl Lashley – “memory is not possible”• Memories are highly distributed

Memory

Organization of experience….what would you do without it?

The ability to retain learned information and knowledge of past events and experiences and to be able to retrieve that information.

Learn ---- Retain ---- Retrieve

Encoding ---- Maintenance ---- Retrieval

Brain Research In the Media…

Short-Term Memory

Sensory Memory

Long-Term Memory

Sight

Sound

Taste

Touch

Smell

Attention

Elaboration and

Organization

Retrieval

Rehearsal

Lost Lost

Common Model of Memory Processes

Time Course of Memory Processes

Memory Processes Sensory

Holds information for a fraction of a second

Perception and attention

Short Term

Information remains for about 15-20 seconds

Chunking

Rehearsal: Rote and Elaborative

Long Term

Information remainsfor days, months,and years

Retrieval:

More frequent activation of neuron patterns leads to more efficiency

Memory Dichotomies

• working (short-term) vs. long-term• episodic vs. generic • explicit vs. implicit • procedural (riding a bike) vs. declarative

Types of MemoryWorking memory: An active system for temporarily storing and

manipulating information needed in the execution of complex cognitive tasks  (e.g., learning, reasoning, and comprehension) (Baddeley 1986)

– The “magic number” (+ 7) for digit span, and more.– Sets a limit on performance, good thing?– “Loading platform” for long term memory

149162536496481

Memory Processes

• How do memories get from working memory to long term memory storage?– consolidation

• How do we get them back?– Retrieval– Indexing

What Facilitates Encoding, Consolidation, and Maintenance?

• Time spent in working memory? rehearsal?

• Attention and engagement• Connection to what we already know• Depth of processing (typeface vs.

meaning)

What Facilitates Retrieval?

• Memory cues & context• Depth of processing, easier to find• Retrieval failure or memory loss? Or

forgetting vs. misplacement?

Forgetting

We are forgetting all the time.

Decay-- metabolic processes undo “memory traces”

Displacement-- awake vs. asleep during recall interval, interference

1 4 9 16 25 36 49 64 81

ta-da!

Long Term Memory

Squire & Zola, PNAS, 1996

Squire’s Taxonomy of Memory

Memory Disorders

Two main types of Amnesia:

• Anterograde (“forward”) Amnesia

• Retrograde (“backwards”) Amnesia

Memory Disorders

Anterograde Amnesia• Problem: forming new memories

post-injury/operation• Korsikoff’s Syndrome (chronic alcoholics),

Alzheimer’s, patients like H.M. with hippocampal/thalamus damage

• Can read, write, converse, remember life until damage was done

• “Right now, I’m wondering, Have I done or said anything amiss? You see, at this moment everything looks clear to me, but what happened just before? That’s what worries me. It’s like waking from a dream; I just don’t remember.”

• “…Every day is alone in itself, whatever enjoyment I’ve had, and whatever sorrow I’ve had.”

H.M.:

Memory Disorders

Retrograde Amnesia:• Problem: loss of memory for some period before

brain injury• ECT and head traumas• “Trace consolidation theory” -- memory hasn’t had

time to become firmly established, but... several years?

• Sometimes memories do come back gradually

Memory Disorders

What amnesiacs can do:

• procedural memory tasks (mirror tracing)

• implicit memory tasks • behavioral conditioning

Squire & Zola, PNAS, 1996

Squire’s Taxonomy of Memory

Memory in the BrainOther important brain areas and functions:• Pre-frontal cortex—retrieval, working memory• Hippocampus & other parts of Thalamus--

consolidation• Amygdala--emotional events, fear

conditioning• Occipital & Temporal Lobes— visual/auditory memories