AGING AND MEMORY

• The aging of America

• Conventional wisdom on aging and memory

• Neurobiological changes [demo]– Neural mass decreases, 5-10% / decade

• Shrinkage; atrophy of “white matter”• Frontal lobes particularly vulnerable• Some atrophy, little cell loss, in

hippocampus– Decreases in neurotransmitters

• Acetylcholine from basal forebrain• Dopamine receptors in frontal lobes

– Decreased blood flow, metabolism– Less “functional activation”

• Left anterior frontal during encoding• Right anterior frontal during retrieval

HOW MEMORY CHANGES

• The myth of inevitable, global decline

• Deficits may be due to other factors:– General health problems– Medication– Depression– Self-concept, sense of “efficacy”– Educational level– Motivation and task engagement– Specific disease (e.g., Alzheimer’s)

• Age-related declines seen . . . More in Than in

Kinds of memory:

declarative procedural

explicit implicit

episodic semantic

recent remote

Types of tasks:

complex simple tasks

unfamiliar familiar tasks

distractor no distractor

divided full attention

recall recognition

• Processes that are especially vulnerable:– Speeded information processing (the

“general slowing hypothesis” of Salthouse)

– Effortful, strategic encoding, more so retrieval (the “reduced resources hypothesis” of Craik)

– Source monitoring and memory

– Executive function, elaborative encoding and retrieval

Simon (1979): Cued recall

The farmer drove the truck

Free Cued

Young .50 .70

Old .25 .25

(Cherry, et al. 1993): contextual cues and “causal elaborations”

• The grimacing man held the cheese..

. . as he reached for a salt cracker.(nonexplanatory context)

. . as the mousetrap caught his finger.(explanatory context)

Type of context

nonexplanatory explanatory

Base Full Base Full

Young .22 .47 .21 .76

Old .06 .20 .10 .59

– Executive control in working memory (Baddeley)

Salthouse & Babcock (1991) : “computation span”

– Attentional allocation, inhibition of potential distractors from task or memory (Hasher & Zacks)• Broader context-priming effects• Greater stroop interference• More PI intrusions

0

2

4

6

8

20 yr 70 yr

Study Task

Me

an S

pan digit span

computationspan

AGING AND MEMORY

• Taking the edge off aging– Stay healthy and engaged

• Regular aerobic exercise• Nonroutine, challenging daily activities

– Provide meaningful organization and structure to tasks

– Allow adequate time for encoding and retrieval

– Minimize distractions, keep tasks simple

– Provide extensive practice on new tasks, continued practice on old skills

• Reminiscence in the elderly– Seeing coherence in one’s life story– Providing continuity over the

generations

Mental Exercise and Mental Aging

• The “use it or lose it’ hypothesis– Evidence of “protective function” of

mental activity Rutgers Newsletter– Salthouse (06): the need for longitudinal

comparisons

Suggests that mental activity does notAffect rate of decline with age

Alzheimer’s and Memory

• Demographics– C. 4 million afflicted, accelerates with

aging (50% of 85 yr+)– 3rd leading cause of death– Costs approaching $100 billon annually

• Etiology– Ultimate causes unknown– Immediate cause is degeneration of

neural structure• Loss of mass, neurons• Impaired acetylcholine levels• Plaques of neural debris• Neurofibrillary tangles within neurons

• Early symptoms of dementia– Memory loss: misplacing things,

forgetting to do things, disorientation, repetition in converstation, retrieval of familiar words and names

– Procedural memory: deficits in performance of “simple” routine tasks; dressing, cooking, etc

– Poor judgment: e.g., wrong clothes, inappropriate social behavior

• Progressive Dementia– Increasingly severe impairment in

cognitive functioning; semantic memory, language, autobiographical memory

– Loss of motor control– Loss of self– The challenge to families

fMRI and agingMemory Retrieval (Miller, 03)

Top row: young adult (20 yr)Bottom row: old adult (70 yr)

Source Memory Problems and Aging

Bartlett, et al (1991)False fame judgments

0.00

0.10

0.20

0.30

0.40

0.50

zero One Two

Study exposures

Pro

po

rtio

n f

als

e

"fa

mo

us

"

Old

Young

• Session 1:• view nonfamous faces• detect repetitions

• Session 2 (next week):• view S1 faces, other famous and nonfamous faces• judge fame

Episodic Memory Deficits in Alzheimer’s Disease

La Rue, 1992: WMS loss (%)

Paired associate recall 34

Paired associate recognition 5

Memory for visual detail 65

Story memory 80