Long-term Memory

Memory Terminology
• Types of Long-term memory
– Episodic memory
• Personal memory
– Semantic memory
• Generic knowledge
– Procedural memory
• Learning how to do things
• Encoding versus Retrieval
– Creating memories versus remembering

• Modal view of memory (qualitative differences
between STM and LTM)
– Capacity
• STM around 7 chunks, LTM nearly unlimited
– Duration
• STM around 30 seconds, LTM can last a lifetime
– Bahrick (1984) memory for Spanish class declined during first 6
years, but there was no further forgetting even out to 35 years
– Coding
• STM is acoustic
– confuse “b” and “g”
• LTM is semantic
– Baddeley (1966a) – 20 minutes after studying a list
» poor recall for semantically similar lists (HUGE, BIG, SIZE,
etc.)
» normal recall from acoustically similar lists (MAD, MAP,
MAN, etc.)

A Unitary Account of Memory
• levels of processing: the only difference between STM
and LTM is whether encoding is “shallow” or “deep”
– memory is a continuum, rather than different modes
– deep processing is more semantic and self-referential and
results in stronger, longer lasting memories
• Semantic memories are more distinctive (unique)
• Semantic memories involve elaboration (interconnected)
– shallow processing is concerned with physical characteristics
and results in weaker, temporary memories
– Craik and Tulving (1975) had participants study words with the
following tasks (listed from worst to best memory)
• Is it in upper case?
• Does it rhyme with ?
• Does it fit in the sentence ?

Long-term Memory
• Tests of long-term memory
– recognition
• how to measure performance?
– increased “hits” (saying old to targets) could be a bias to
always say old
– compare the hit rate to the false alarm rate (saying old to
distractors / foils / lures)
» If familiarity is compared to a criterion, bias and memory
can be separated
– free recall
– cued-recall (paired associate learning)
• study FLAG-SPOON, DRAWER-SWITCH, etc.
• FLAG-______
– results are similar to free recall

Results
• Forgetting Curves
– Ebbinghaus’s (1885) nonsense syllable experiment
• over the course of days, he kept on relearning lists of nonsense
syllables (e.g., RUR, HAL, BEIS, etc.)
• forgetting was measured as percent savings (a comparison of
immediate testing versus testing after a delay)
• information is rapidly forgotten at first (non-linear)

Results cont.
• recall is better when context is kept the same
– encoding specificity
• Thomson and Tulving (1970) – word context
– e.g., studied ‘ground-COLD’
» better recall with ‘ground-?’ than ‘hot-?’
• Golden and Baddeley (1975) – environmental context
– words learned on land or underwater
– words tested on land or underwater
memory
performance
study
on land
study
underwater
test
underwater
test
on land

– encoding specificity cont.
• Marian and Fausey (2006) – language context
• Bransford et al. (1979) – processing context
– Rhyme encoding produces best performance if rhyming
is also used at test (deep processing isn’t always best)

– encoding specificity cont.
• state-dependent learning – a match between
pharmacological states improves memory (Eich, 1980)
memory
performance
study
drunk
study
sober
test
sober
test
drunk
• mood congruence – a match between moods states
affects memory (Murray et al., 1999)
– Depressed people recalled less than nondepressed people
– Nondepressed people recalled many more positive words
than negative words
– Depressed people recalled slightly more negative words
than positive words

Results cont.
• memory is worse when semantically similar
items are studied
– A,B,C, vs. A,A’,A’’ (false memory effect)
• memory for any particular item is worse when
more items are studied
– A,B,C vs. A,B,C,D,E,F (length effect)
• memory is better when each item is studied for a
longer period of time
– A,B,C vs. A,A,A,B,B,B,C,C,C (strength effect)
– however, distributed study is better than massed
study
• spacing effect
– A,A,A,B,B,B,C,C,C vs. C,A,B,A,B,C,B,A,C
– Encoding variability

edspread
betrayal
donate
escapade
holly
iceberg
missile
numeral
outcast
painless
plumber
plural
priority
rancher
reversal
skeleton
trigger
trinket
waffle

Amnesia

• Bilateral damage to the medial temporal lobes (including
the hippocampus)
– inability to make new memories
• anterograde amnesia
– some loss of old memories from just before the damage
• retrograde amnesia
– sources of damage
• permanent: Surgery, stroke, hypoxia, head injury, encephalitis
• progressive: Korsakoff’s syndrome, Alzheimer’s disease
• temporary: electroconvulsive therapy (ECT), benzodiazepines
• unilateral hippocampal damage
– left = verbal memory
– right = spatial memory
• hippocampal versus parahippocampal damage
– recall versus familiarity?
brain
damage
PAST PRESENT
retrograde
anterograde

• Anterograde amnesia
– Inability to form new long-term episodic
memories
• general knowledge and personal history are frozen
– poor at recall, recognition, etc.
– no new vocabulary (e.g. jacuzzi, granola, etc.)
• intact STM / working memory
• all modalities affected
• Skill learning
– Implicit learning, but no explicit memory (dissociation)
» procedural versus declarative
– motoric or perceptual (i.e., cannot learn chess)
» rotary pursuit
» mirror tracing
» mirror image reading
» new words (not meaning)
» long-term priming (stem and fragment completion)

ed__
bet__
don__
esc___
hol___
ice___
miss___
num___
out___
pain___
pl_m__r
p_ur_l
pr_o_ity
ra_c_er
re_e_sal
s_el_ton
t_ig_er
t_in_et
w_f_le

• Retrograde amnesia
– loss of old memories
• some retrograde amnesia with hippocampal damage
– the period just before the injury is forgotten (temporally graded)
– memory consolidation (Squire)
• Memories are dependent on the hippocampus for awhile
– with time, the cortex can learn the memories
– this process is called memory consolidation

Narrative and Autobiographical Memory
• Do laboratory studies apply to real life memories?
– Bartlett (1932) thought narrative memory is often
reconstructed based on schemas
• Schema: general knowledge or expectation distilled from past
experiences (i.e., the ‘gist’ of things)
– e.g., the ‘eating lunch’ schema
• constructivist view of LTM
• serial reproduction: repeated recall the same story
– Native American story, “War of the Ghosts”, became more distorted
and westernized with each reproduction
– Consistency bias
• Memories are made to be consistent with current self-schema
– Source monitoring errors
• Attributing a memory from source A to source B
– Reality monitoring errors
• Thinking something happened that was just imagined or
planed

– Autobiographical memory for ordinary events
• Marjorie Linton (1975, 1982) spent six years recording the daily
events in her life (2 per day) in a systematic fashion
• each day short descriptions of important events
– the date, how distinctive, how emotional, importance to life goals
• tested herself at delays up to three years
– order two events (which happened first)
– provide exact dates of events
• performance was good at all delays
– real life memories are more durable than what Ebbinghaus found
– she often used problem solving to arrive at the dates of events
» constructivist view of memory
• events that she could not recall where often similar to other events
she could not recall
– repeated similar events can start to form a schema

Flashbulb Memories
(Brown & Kulik, 1977)
• personal events at time of disaster
– JFK assassination, Challenger explosion, start of gulf war, 9/11
• physiological response
– emotional response causes hormone release
• better encoding
• However, positive events better remembered than negative (see pp.
137-140)
– Students in NYC recalled more facts than students in California
• stronger emotional responses = more details

• Weaver (1993) compared intentional memory to
flashbulb memory
– remember next meeting with roommate
• Tested immediately, 3 months, 1 year
– gulf war started at same time (direct comparison)
• No accuracy differences
• Higher confidence for flashbulb
• Talarico & Rubin (2003) compared forgetting of flashbulb
memory to ordinary event

Own Race Bias (ORB)
• People are best at remembering and perceiving
faces of their own race
– Contact hypothesis (Walker & Hewstone, 2006)

ORB and Cue Utilization
• Different races make different eye cosmetic
alterations
– Caucasians: 85% of people who wear soft contact
lenses wear colored lenses (Contact Lens Council, 2000)
– Asians: 39% of plastic surgeries are blepharoplasties, or
double eyelid surgeries (AAFPRS, 2007)

proportion of
descriptions
0.6
0.5
0.4
0.3
0.2
0.1
0
Descriptors Used
Iris Color Eyelid Crease
Asian test face Caucasian test face
Asian Caucasian
Participant race
60
50
40
30
20
10
0
Asian Caucasian
Participant race

Eyewitness Memory
• memory integration (malleability)
– Elizabeth Loftus (1978): series of accident slides
• Viewed stop or yield sign
• “Did another car pass the red Datsun while it was stopped at the
stop/yield sign?”
• recognition of slides
– two alternative forced choice testing (2-AFC)
» no need to compare hit and false alarm rates
» Post-event misinformation effect (retroactive interference)

Eyewitness Lineups
• what’s the best way to conduct a lineup?
– maximize identification of guilty suspects (hits)
– minimize identification of innocent suspects (false alarms)
• selecting distractors in a lineup (known-innocents)
– the use of mock eyewitnesses
– match-to-description, or also resemble-suspect?
• either way, innocent suspect is protected
• if distractors resemble-suspect, identification of guilty suspect is lower
• demand characteristics
– subtle cues
– exert pressure to select (relative judgment)
– double-blind eliminates these concerns
• Not adopted by law enforcement
• relative judgments versus absolute identification
– sequential lineups emphasize absolute identification
• reduces identification of innocent suspects
• however, also reduces identification of guilty suspect
• w/o double-blind, can increase demand characteristics

False Memory Effect
• Deese (1959) and Roediger
and McDermott (1995) (DRM)
– False recall of critical lure*
– False alarm rate for critical lures*
as high as hit rate
• Explained by summed similarity to
all memories (Shiffrin, Huber, &
Marinelli, 1995)
Test List
Patient
*Doctor
Rest
*Sleep
Nurse
Sick
Medicine
Health
Hospital
Dentist
Physician
cure
Patient
Office
Study Lists
Surgeon
Bed
Rest
Awake
Tired
Dream
Snooze
Blanket
Doze
Snore
Nap
Yawn

Recovered Memories
• Therapy and police interrogation can result in
recovered memories. Are these real?
– Practices that might cause false memories
• Hypnosis
• Imagination exercises
• Leading questions
– Memories can be implanted
• Loftus and Pickrell (1995): 3 true events and one false
“lost-in-the-mall”
– Booklets describing stories (4-6 years) were created by
interviewing relatives
– Participants asked to fill in additional details
– 68% of true stories and 29% of false stories ‘remembered’

• Hyman, Husband, and Billings (1995)
– embarassing stories (e.g., spilling punch bowl at a wedding)
» 80-90% of true events
» no false events recalled in first interview
» 20% in a second interview
» some participants elaborated upon their false memories
(added details never presented)