Week 9

Question 1

What is memory?

Answer 1

• What is memory?
• Preservation of experience, including
sensations, emotions, thoughts and
beliefs
• Not just preservation
• Actionable preservation
• need to be able not just to store
information, but also retrieve it in a
manner such that we can act on it

Question 2

SEMANTIC

Answer 2

Non-contextual
Abstract
Non-autobiographical
What is a giraffe?
Read/identify Giraffe

Question 3

EPISODIC

Answer 3

Context-sensitive
Personal
Autobiographical
Did you see a Giraffe at the zoo last
week?
Did ’Giraffe’ appear in the list of words I
gave you earlier?

Question 4

Episodic and semantic memory

Answer 4

• Most of our cognitive activities, decisions and action plans
use both episodic and semantic information
• Watching a movie
• Identify objects, interpret speech, recognise
situations (semantic)
• Remember plot, prior actions of characters
(episodic)
• IMPLICIT memory - effects of a recent study phase on
semantic memory tasks, knowledge questions

Question 5

What is human memory like?

Answer 5

• What is needed in a workable human
memory system?
• Access past experiences and knowledge
that can help with dealing with a current
situation
• A filing system that allows us to access
the relevant information
• Forget similar memories that no longer
apply
• where did I park the car today? (not
all the past days of this month).
• Do this job efficiently during ongoing
actions

Question 6

Computers as memory machines

Answer 6

Memory organized by topic, date, time, place
Memory accessed from pre-defined cue
Rapid serial search of memory
Information completely & accurately
represented in memory
Information is not altered during storage or retrieval
Memories remain separate within the memory system
Details of context of occurrence and
source of memories are retained

Question 7

Humans

Answer 7

Memory organized by experiences,
significance of information
Memory access-cue less well specified
Slower memory access
Only part of an experience is stored according to personal relevance
Information is re-interpreted or
distorted over time & during retrieval
Generalisation & composite memories, interference
Source information may be lost

Question 8

Implications

Answer 8

• Legal testimony
• A traditional idea that eye-witness testimony is compelling
• I saw the robber with my own eyes!
• But in fact researchers have
shown that identification errors in line-ups can easily be made
• What witnesses recall must be what is stored in memory (unless they are lying)
• Memory researchers have shown that remembering is effortful and its success
depends on good retrieval cues
• Suggesting to witnesses what they must have seen is risky!
• On repeated questioning, witnesses may remember something that was suggested
during prior questioning
• Without realising the source of this info - misinformation effect.

Question 9

Short-term vs. long-term memory

Answer 9

• Memory over the short term distinguished
from vs. more permanent memories
• Short-term memory (STM) also called working
memory (WM)
• WM reflects ideas about cognitive workspace
• Memory used for current actions - duration of
several seconds or minutes
• Long-term memory
• Information in a more permanent store
• Must be retrieved for use

Question 10

Evidence for the STM vs. LTM distinction

Answer 10

• The serial position curve
• Central finding, goes back to Ebbinghaus
• Murdock (1962) asked Ps to remember lists of 10 - 30
words, each presented singly for a second or two.
• Free recall test - say any words you remember in any
order
• Memory accuracy depended on position in which a word
occurred in the study list
• best = items at beginning, end
• worst = items in middle

Question 11

The serial position curve

Answer 11

Primary and recency effects

Question 12

Interpreting the serial position curve

Answer 12

• Primacy effect reflects transfer of items to long-term
memory
• Recency effect is found for later list-items that are still
“fresh” in WM
• When Ps were asked to count backwards by 3s from 100
at the end of the study list (loading WM)
• The recency effect was eliminated
• But not the primacy effect
• Thus, the serial position curve shows a distinction
between long and short-term memory

Question 13

Distinguishing LT and ST (working) memory

Answer 13

• Other distinguishing features of STM compared with LTM
• STM has low capacity
• Forgetting due to decay and interference from later and prior items
• Miller (1956) proposed “the magical number 7” for STM capacity
• Number of items or meaningful chunks
• Recent evidence suggests that original estimates were optimistic
• Perhaps 4 is a better estimate (Cowan, 2000).
• STM is highly sensitive to order of item presentation

Question 14

Linking STM & LTM - the “Modal Model”

Answer 14

• Atkinson & Shiffrin (1968)

* Integrated findings into “modal model” of memory several memory ‘stores’

Question 15

Modal model

Answer 15

• Sensory stores
• Handle initial sensory analysis
• modality specific - one for vision, touch, sound
• High capacity, but material decays quickly unless moved to short-term store
• Short-term store
• Holds in memory what is needed for current actions
• Control processes involved in rehearsal, coding (chunking),
decision and retrieval strategies
• Long-term store
• Vast capacity, long-term retention
• Supports short-term store (identify words, objects)

Question 16

STM to LTM

Answer 16

• REHEARSAL keeps material in STM
• Material that is in STM long enough gradually gets
transferred to LTM
• So effectively, rehearsal helps get info into LTM

Question 17

Modal model – criticisms and contributions

Answer 17

• Criticisms:
• Should the sensory systems be considered ‘memory’ processes?
• Rehearsal isn’t what gets material into LTM – see depth of
processing research (next week).
• There is a more complex interplay between STM and LTM, not
a simple sequential transfer of information
• Contributions:
• Idea that memory behaviour is due to the properties of different
stores or systems (information processing) remains influential
• Influenced the development of the most influential account of
short-term memory, Baddeley & Hitch’s 1974 model

Question 18

Tasks for long-term memory

Answer 18

• Ps study word lists and then asking Ps to remember what was in
the list
• Episodic
• Intentional retrieval – “explicit”
• Ps not necessarily told at study that they will be tested
• “Gold standard” tasks are recall and recognition
STUDY PHASE
See words one at a time for a few seconds each.
Perform some task on each - e.g., rate pleasantness
RETENTION INTERVAL
Minutes, hours or days
RECALL TEST
Say or write the words
from the study list
RECOGNITION TEST
Was the word
mouse in the study
list? Yes (Old) or No
(New).

Question 19

Typical episodic memory experiments

Answer 19

• There are many variations
• Materials
• Nonsense words, faces, pictures, abstract shapes, with and
without verbal labels
• Item vs. relational
• Study single items vs. pairs or groups
• Test single items vs. associations between words, between
words and pictures etc.
• One study trial per item vs. several
• Cues provided or not
• Cues from the study list vs. not

Question 20

Recall tasks

Answer 20

• Dependent variable (DV) = accuracy, i.e., % or number correctly recalled
• Free recall
• Ps produce the words in any order that they wish, until they cannot
recall any more
• Serial recall
• Produce the words in the order in which they were studied
• Long-term serial recall feasible only with short lists - like passwords
• Cued recall
• A cue is provided for each word on the study list - makes recall easier
• for dingo, dog - ? di___ ?

Question 21

Recognition

Answer 21

• Recognition here is short for episodic recognition - old
vs. new
• Single item recognition
• Each memory item (picture, word, feature from face,
etc) presented one at a time for old vs. new decision
• New (unstudied) items usually presented as well
• Record accuracy (sometimes latency also)
• E.g. Choice test
• Which word is old (part of the previous study list)?
house - cottage

Question 22

Accuracy DVs for recognition tests

Answer 22

Recognition is more flexible and sensitive than recall
• Can test all kinds of items that can’t easily be produced (complex shapes, pictures,
symbols, faces)
• More likely to detect memories that are weaker or incomplete
• But interpreting accuracy scores is more complicated
• What does % correct for old items tell us?
• If P has 90% correct on old items
• We can’t say whether memory is good
• Or whether P just says “old” most of the time!
• This is known as a response bias
• Need to take into account False Alarms = old responses to new items

Question 23

Hits, Misses, False Alarms (FA) & Correct Rejections (CR)

Answer 23

Study list
tomato
desk
plateau
squirrel
hostile
biscuit
ocean
textile
ruler
shrub
boot
disaster
plateau?
“OLD”
HIT
plateau?
“NEW”
MISS
train?
“OLD”
FA
train?
“NEW”
CR
train is not in the study list correct answer is “new”

Question 24

Hits and False Alarms (FA)

Answer 24

• If the FA rate is low
• Hits are usually interpretable
• Groups in different experimental conditions can be compared on
Hits if their FA rates are low and similar
• Otherwise FA must be taken in to account
• Analyse and consider both Hits and FA
• Correct Hits for FA by subtracting FA rate from Hit rate
• Apply Signal Detection, to estimate sensitivity and bias separately
• Remember that recognition is a discrimination task

Question 25

Implicit vs. explicit tests of memory

Answer 25

Studies of brain injury and ageing show large differences in memory
depending on how it is investigated (see PSYC2020)
• Traditional episodic memory tests are EXPLICIT (direct)
• Ps are told at test that they should retrieve items that occurred in the study phase
• When Ps do the test, they deliberately and intentionally try to remember just this
memory episode
• In cases of reduced memory function (brain injury), Ps often perform very poorly in
explicit tests
• But Ps with reduced memory function may perform well on IMPLICIT
(indirect) tests
• These are tests in which Ps are asked at test to identify items or
“give the first thing that comes to mind”
• Effects of study on memory can be seen

Question 26

Implicit tests - priming

Answer 26

• Ps perform a study task on a list of words
• animal, kitchen, drivel, ….etc
• No mention of a memory test
• Implicit test: A semantic memory test, no mention of study episode, e.g.,
• Lexical Decision Task (LDT)
flurb kitchen sping Make a speeded word vs. nonword decision
for each letter string
OTHER:
1. Name a briefly presented word - kitchen
2. Complete the stem ki ….. with the first word that comes to mind
3. Free association: What is the first word that you think of when I say “cook”?

Question 27

Summary: Priming in implicit tests

Answer 27

• When a recently encountered word is more available or is better identified in
an implicit test
• “priming” has occurred
• a representation of a word has been made more accessible in memory
• The study presentation of the word may be called the “prime”
• Implicit tests are semantic tests; do not require intentional
episodic retrieval: (memory can be accessed without a conscious
search process)
• But caution!
• Ps who can do so may deliberately retrieve from the study list during implicit tests
• Memory in ageing & brain injury
• A difficulty in the use of contextual information at encoding and/or retrieval
• Can’t use context to retrieve a particular episode

Question 28

Implicit memory in amnesia

Answer 28

• Patients with Korsakoff’s sydrome
• Have difficulty remembering information acquired after the onset of
their illness and acquiring new information
• Schacter, Tulving & Wang, 1981
• Korsakoff’s patients answered multi-choice trivia questions
• used questions were put back in the question pile
• Repeated questions were better answered
• But patients were unable to say that questions had been
seen before!
• So explicit memory is lost, but there are implicit (semantic) memory
effects
• Patients appear to be unable to use contextual and source
information

Question 29

Basic LTM phenomena: Ebbinghaus and forgetting

Answer 29

• Episodic memory tasks date from
Hermann Ebbinghaus (around
1885)
• Used himself as his own subject
• Studied a series of nonsense syllables
until he could recite the series
perfectly twice
• Tested recall of series at different
time delays up to one year
• Used both free and ordered
recall

Question 30

Foundations: Ebbinghaus’ forgetting curve

Answer 30

• The result was a curve that steadily dropped off, and could be
described with a simple exponential equation based on delay
between study and test
• A “forgetting curve”
• Forgetting is systematic, and lawful

Question 31

Forgetting and Memory errors

Answer 31

• The forgetting curve is one of the first robust findings of
scientific psychology
• We lose information over time in a systematic, nonlinear
fashion.
• Why do we forget?
• Is it because information decays, or is it because it gets
blocked as new information comes in?
• DECAY or INTERFERENCE?
• What about our intentions?
• Can we INHIBIT (suppress) memories that are painful or
not useful?

Question 32

Decay

Answer 32

• Decay = memories fade, or connections between them fade if
they are not used.
• Some conceptual and empirical problems
• Conceptual:
• Decay = “loss due to passage of time”
• Forgetting = loss of knowledge over time
• tautology = saying same things in different words
• using time as a stand-in for unknown cause tightly correlated with
time
• Empirical:
• It’s not feasible to get direct evidence of decay at the
neural level

Question 33

Evidence for decay?

Answer 33

• Passage of time may affect mechanisms other than decay
• effectiveness of retrieval cues (e.g., context)
• Sometimes forgotten things can be remembered later:
• So retrieval failure, not decay
• interfering effects of learning occurring after the memory was laid down
• So decay theorists tried to show that memories fade over time even
when interfering material and changes in cues were controlled
• Jenkins & Dallenbach, 1924 - Obliviscence during sleep & waking
• Sleep on it!
• Ps learn information and have a memory test
• Compared recall after sleep for several hours vs. wakefulness

Question 34

Jenkins & Dallenbach

Answer 34

• Sleep group can only forget due to decay
• Awake forgets due to both (potentially) decay + interference
• Results
• Much more forgetting in awake than sleep condition
• Conclusion: Interference the largest source of forgetting

Question 35

Decay vs. Interference

Answer 35

• Limitations of Jenkins & Dallenbach
• Time scale: What if decay matters more at longer time periods
• months not hours?
• Role of sleep in consolidating information: Reverses effects of decay?
• Need more precise theories of decay to get clear tests
• Conclusion:
• Decay may play a role in forgetting
• But researchers agree that interference and other effects located at
retrieval are more important

Question 36

Interference

Answer 36

• Two broad classes of interference effects in retrieval
• Proactive: old information blocks new information
• Retroactive: new information blocks old

Question 37

Rugby players and retroactive interference

Answer 37

Baddeley & Hitch (1977) studied rugby players’ recall of game details over time
• Questioned players from two teams in the pub
• Looked at memory for details (e.g., team names) of various games as a function of
when they were played and how many games were played before and after them
• Decay: Loss of detail not really correlated with time elapsed after the
game
• Found r = .04 for game-memory with time
• Interference: Loss of detail WAS correlated with the number of games
• Found r = .55 for game-memory with number of games played since the
game
• retroactive interference
• Forgetting has more to do with interference than decay

Question 38

Inhibition in memory?

Answer 38

• Repression of unwanted memories?
• Recent publicity about “repressed” traumatic memories of childhood
• Many conceptual and practical problems:
• Events that are very traumatic are often well-remembered
• Due to effects of arousal on memory encoding
• Difficult to establish facts from many years ago
• Events early in childhood may not be well understood at the time
• memories may be poorly retrieved because they are fragmented and difficult to
interpret.
• Court cases - The “Memory Wars”

Question 39

“Recovering repressed memories”

Answer 39

It is not established whether memory repression does occur
• Some techniques designed to “recover” repressed memories can
create false memories
• Therapists should engage in repeated questioning with care
• Must avoid suggestions about repressed memories for possible
childhood trauma, abuse
• The problem is human difficulty with source memory
• Where, when, who, how of things remembered
• did I see it in a movie, read it in a book, imagine it? who
told me?
• Suggestions made in questioning may be later remembered as
actual events because their source has been forgotten.

Question 40

“Recovery” of false memories

Answer 40

• Elizabeth Loftus - misinformation effects
• Classic studies showed reduced memory accuracy
in witnesses when incorrect information given
during questioning
• Did the blue car turn right? (but actually it was a
green car)
• Application to “recovered memories”
• (Braun et al., 2002) Ps were asked to rate
advertisements on various characteristics
• Including a false ad with Bugs Bunny at Disneyland
• Impossible: Bugs Bunny is Warner Bros, not
Disney
• On later questioning 16% of Ps claimed to have met
Bugs Bunny at Disneyland.

Question 41

Interpretation of false memory effects

Answer 41

More traditional and well-controlled laboratory paradigms have shown false
memories
• Deese, Roeidger & McDermott paradigm (DRM)
• Ps study a list of related words - bed, dream, wake, tired, blanket, yawn
• About 50% of the time, Ps falsely recall and recognise sleep as being on the list
• and also claim to have a clear memory of seeing it in the list
• False memory and misinformation effects show that memory retrieval is
a re-constructive process
• and reinforce the difficulty of recovering accurate source information
• Recovery of repressed memories:
• Memory researchers now recommend that independent objective evidence be
found before courts rely on reports of recovery of repressed memories