Remembering and Forgetting Ebbinghaus Nonsense Syllables ...

Ebbinghaus
Remembering and Forgetting
• First person to use experimental design to
study memory
• Methodological concerns:
– If you want to study learning, it is best to find
someone who has no prior experience
• If you are studying how people learn psychology
concepts, your subjects should not be psychologists
–
• Nonsense Syllables
• Defined:
Nonsense Syllables
– More importantly, these syllables have no
meaning, and the words have never been learned
– VOX, TIL, JIV
– Because words have no meaning, any memory of
the words is due to experimental conditions, and
not to previous experience
Number of Syllables and
Rehearsal
• Ebbinghaus memorized lists of
varying numbers of nonsense
syllables
– Wanted to examine whether
– He found, of course, that is does
– The longer the list, the more
effort it takes to learn the list
Ebbinghaus’ Contributions
• Brought the study of memory into the realm
of scientific study
• Helped to establish learning and cognition
as legitimate subject matters in psychology
• Savings:
– When people forget information, all is not lost
Bartlett
• Claimed that Ebbinghaus’ nonsense syllables were
problematic
– In the real world, people are more likely to be asked to
remember familiar material
–
• Material is likely to be rehearsed by relating it to other similar
information already in memory
– Research on memory should focus on conventional
functions in the real world, not learning of nonsense
syllables in artificial laboratory setting
1

Bartlett’s Experiment
• Presented subjects with folk stories, short
essays, and descriptions of human activity
• Then would ask subjects to reproduce
information
–
– Related to one of today’s hot topics in memory:
Fuzzy Trace Theory
Fuzzy Trace Theory
• Gist vs. Verbatim Memory Traces (Reyna and
Brainerd, 1995)
–
–
– Younger children rely on verbatim recall; Older
children more dependent on gist
– If memory is tested soon after the to-be-remembered
event, individuals depend on verbatim recall
• As delay increases, verbatim decays, and use of gist increases
Bartlett’s Contributions
Information Processing:
The Stage Model
• Recognition that memory is not veridical
– In other words, memories are not exact
reproductions of the remembered event
– Memories are ____________, with knowledge,
schemas, and scripts filling in the details
– Any recall of an event is composed partly of
actual memory, and reconstructions using
memory from similar events
• Defined:
The Sensory Store
– How much information is available to sensory
store is limited by sensory receptors
• This information is stored in sensory store for a brief
period after stimulus is no longer acting upon
sensory receptors
Experiments on the Sensory Store
• Sperling (1960): Participants shown
matrix of letters for 1/20 of a second
• A tone then indicates which row the
subject should try and remember
•
– A good deal of the matrix is available in
sensory store immediately after it is
presented
• If tone delayed even briefly, the
number of items recalled drops
drastically
• Led to idea of Iconic Image
2

Types of Images in Sensory Store
• Iconic image:
• There is also evidence of Echoic Images:
Short-Term Store
• People must attend to or rehearse
information actively if it is to make its way
from the sensory store to the next
processing stage: the Short-Term Store
• Defined:
Characteristics of
Short-Term Store
• Contains words, images, numbers, etc. that
are being attended to at a given moment
• Miller’s Magical Number:
–
– Depends on how you define “item”
• Remembering seven six letter words
– Could either be seen as remembering 7 words, or 42 letters
• Related to the idea of chunking
• Defined:
Chunking
– Each item can contain considerable information
– Acronyms:
• SCUBA (Self-Contained Underwater Breathing Apparatus)
• PTA (Parent-Teachers Association)
• KFC (Kitchen-Fresh Chicken???)
– Phone numbers: hyphen creates two chunks of numbers to
remember
Long-Term Store
• If information is not kept active in shortterm
store, it will be lost within 20-30
seconds
– Repeated rehearsal of information in the shortterm
store leads to a transfer to long-term store
• Defined:
– Permanent in the sense that it is available for
retrieval, given appropriate retrieval strategies
Three types of long-term memory
• Episodic memory
–
• e.g. birthday party
• Procedural memory
–
• e.g. riding a bicycle
• Declarative (semantic) memory
–
• e.g. Your instructor thinks Paul Walker is terrible
3

Criticisms of Stage Model
• Craik and Lockhart (1972)
– Argue distinction between short- and long-term
stores is unimportant
• At what point has information moved between the two?
– Stage model suggests that it is the number of
repetitions that determines whether information
will be recalled
•
Levels of Processing Theory
• In response, Craik and Lockhart (1972)
proposed the levels of processing theory
• Defined:
– Some possible levels of processing a word
• Physical features (upper- vs. lowercase)
• Sound (another word that rhymes)
• Meaning (place word in category or sentence)
– Best recall for this last level of processing
Types of Rehearsal
• The Stage Model refers to maintenance
rehearsal
– Defined:
• Poor strategy: tends to work n the short-term, but not
beyond
• Elaborative rehearsal is a better strategy
– Defined:
Forgetting:
Back to Information Processing
• Encoding: information is placed into information
processor
• Storage: retention of information over time
• Retrieval:
– Failures can occur at any of these stages, leading to…
• Forgetting:
– Notice the difference here from usual definition of
forgetting: inclusion of failure at encoding
• Defined:
Decay Theory
• Problem with decay theory is that it is not
really testable
– Say you tested subjects after varying delays,
and find that with increased delay, there is
increased forgetting
– Are differences are due to decaying, or to
interference caused by subsequent processing?
• Defined:
Interference Theory
• Two types:
– Proactive Interference:
• Material learned for Exam 1 hinders learning of Exam 2 material
– Retroactive Interference:
• Learning material for Exam 2 causes you to forget Exam 1 material
• What makes interference more likely?
– Similarity of the material to be recalled
4

Defined:
Amnesia
Improving Memory
Two types to discuss:
Retrograde Amnesia:
Anterograde Amnesia:
• Because there are many possible sources of
memory loss, a good deal of attention has
been given to strategies that can improve
memory functioning
– Mnemonics
– Distributed Practice
– Encoding Specificity
– State-Dependent Learning
– Elaborative Rehearsal
Mnemonics
Distributed Practice
• Defined:
– Video
• Cramming is a poor strategy for encoding
information into long-term memory
– Say you are going to study for a total of one
hour
•
• Defined:
Encoding Specificity
State-Dependent Learning
• Defined:
– Studying in a similar environment to the testing
environment will help increase recall
• Likely to do worse on the exam if you study in a
recliner, with music on, and in the company of
friends
• None of these stimuli will be present in the testing
environment
– Similar to encoding specificity, except these are
internal, not external, cues
– If you ingest a lot of caffeine to stay awake
during testing session, it is a good idea to have
a similar amount of caffeine before testing
– Emotional states at encoding also important
5

Elaborative Rehearsal
• As discussed before, simple repetition of material
is unlikely to produce long-term effects
– Stop after every few paragraphs and think about what
you have read
– Go back to major concepts and paraphrase them
– Relate new material to previous material in meaningful
ways
– Relate material to yourself or others you know
• All of these strategies encourage a deeper
processing that can help with mastery of material
• Defined:
Incidental Memory
– A significant amount of information processing
is unconscious
– Memory is far from perfect though
• Can lead people astray in ways that can produce
serious consequences
• Eyewitness Testimony
Eyewitness Testimony
• Witnesses to crimes are often asked to
describe in detail what they witnessed
– Ability to do so has huge implications
• Decisions in legal cases usually a direct result of
eyewitness testimony
• Wrongly convicted people lose freedom
What Influences
Eyewitness Testimony?
• How questions are asked during the trial (Loftus
and Palmer, 1974)
– Showed groups same video of car accident
– Later given questionnaires, with slightly different
phrasing
• “How fast were the cars going when they ______ each other?
– Contacted, hit, collided, or smashed
– Later asked to give estimates of car’s speed
•
•
–
• Confidence
–
What Influences
Eyewitness Testimony?
– Problematic because jurors are more likely to trust
witness who is confident in their testimony
• Back to Fuzzy Trace Theory
– People likely to rely on gist, especially at a trial that is
long after crime
–
•
– Makes eyewitness testimony especially prone to
inaccuracies
• Loftus (1997)
–
False Memories
– In such studies, subjects often report high
degrees of certainty
• Confidence can not be used as index of accuracy
6

Plausibility and False Memories
• Pezdek et. al (1997)
– Jewish and Catholic high school students read
two true and two false events
– One false event describes Shabbot; the other
Communion
–
Knowledge and False Memories
• Greenhoot (2000)
– Kindergarteners’ recall of a story was impacted
by prior information
– Before stories are read, description of
protagonist as either nice, mean, or neutral
–
Development and False Memory
• Predictable relationship between age and false
memory
–
• What really matters is the method of
questioning
– Even preschoolers, if questioned without the use of
a suggestive interview, can be competent witnesses
–
• Defined:
Implicit Memory
– Related to the idea of source monitoring
•
• Poses a problem again for eyewitness testimony
– You are shown a lineup of subjects, and you point to
the one you recognize
• What if you just recognize him from the mug shots?
• Or what if he just shops at the same grocery as you?
• Defined:
Flashbulb Memory
– May remember date, where you were, who you
were with, what you were wearing, etc.
Accuracy of Flashbulb Memories
• In one study, subjects asked to report their
recall of the Challenger explosion 3 days
and 9 months afterwards
– Despite high-rated vividness at both occasions,
the details differed substantially
– Possible explanation: perpetual reinstatement
• The events surrounding a flashbulb memory are
likely to be discussed frequently, and revisited in
news broadcasts, etc.
•
7

Memory in Nonhumans
• Continuity –
• Like human infants, animals cannot tell you
whether they remember something
– Because of this, researchers must rely on the
research methods of equipment of learning
psychologists
• Using these techniques, the researcher is able to
make inferences about memory in animals
Memory for Visual Stimuli
• Delayed-matching-to-sample (DMTS) task
– Pigeon pecks middle of three keys and it changes
into sample stimulus (e.g. geometric shape)
– Followed by retention period in which pigeon must
remember sample stimulus
–
• Incorrect responses lead to time-out
Performance on DMTS
• Exposure to sample stimulus
– Better performance on DTMS when sample
stimulus is illuminated…
• Retention interval
– Better performance with ________ _________
between sample stimulus and comparison phase
• Time between trials (intertrial interval)
– Shortening time between trials results in
______________________________
Adaptive Nature of Memory
• People seldom think about their own memory until
they experience a memory failure
– Adaptive because most memory processes occur
without conscious awareness
– Memory allows for less effort when engaging in a wellmastered
task
• Ability to adapt to one’s environment would be
impossible without memory
–
8