Transcript Learning and Memory

Learning and Memory
• Can they be understood separately?
• Learning is the process of acquiring new information, while
memory refers to the persistence of learning in a state that
can be revealed at a later time
• Memory is any indication that learning has persisted over
time. It is our ability to store and retrieve information; to
remember (recognize or recall) things we have experienced,
imagined, or learned
Memory
• The Atkinson-Shiffrin information-processing or multistore memory model sees memory as comprised of
three processes
– Encoding
– Storage
– Retrieval
The Multi-Store Memory Model
Atkinson and Shiffrin’s Multi-Store Memory
Model (1968)
• Memory consists of three stages based on how long memory
is retained (duration) and how much can be stored (capacity).
Three “stages” of memory
– Sensory register
– Short-term memory (working memory)
– Long-term memory
Sensory Register (aka Sensory Storage aka
Sensory Memory)
• A sensory-based, temporary representation of input.
The first stop for all sensory information
– Iconic (visual) Less than .5 seconds
– Echoic (auditory) Two to three seconds
• Decays quickly
• Immense capacity limited only by our sensory
system’s abilities
Sensory memory: Iconic store
• Sperling (1960)
determined the capacity
and duration of the
iconic (visual) store with
a series of ingenious
experiments
• Full versus partial report
method
Sensory memory: Iconic memory
• The partial report technique demonstrated that the
capacity of iconic memory is quite large
• Participants could perceive much more than they could
verbally report
• Information was being read out from a rapidly decaying
icon
Observations about Sensory
Register/Storage/Memory
• Sensory memory holds briefly presented stimuli to increase
the chance that they will be present long enough to be
attended to…
• …when this happens the stimuli enters short term/working
memory
• Allows for “stream of consciousness”, rather than a series of
disconnected images and sounds (e.g. film)
Short-term Memory (often also referred to as
Working Memory)
• The part of memory where information from
sensory memory and long-term memory are made
conscious
• Information is maintained in STM via maintenance
rehearsal. Without rehearsal there is a rapid decay,
e.g., repeating an unfamiliar phone number until
you dial it
• Primarily a process of acoustic encoding
Short-term Memory and Acoustic Coding (and
interference)
• Experiments prove phenomena
phonological similarity effect
known
as
• Which list is most difficult to recall? (Conrad)
– E, F, M, P N
– D, P, T, Z, V
– W, L, C, S, R
• Which of these lists is most difficult to recall?
(Baddeley,et.al)
– large, big, immense, huge, obese
– fish, door, awkward, map, love
– fan, can, plan, ran, tan
ST/Working Memory - Capacity and
Chunking
• George Miller (1956) demonstrated that short- term
memory capacity is about seven (plus or minus two)
units of information (phone #)
• This can be extended through a process known as
chunking (e.g. telephone numbers). Example of
chunking
– Recall the following sequence of letters….
– FDRTVFBIJFKCIA
– The sequence when chunked into meaningful units…
– FDR TV FBI JFK CIA
ST/Working Memory - Capacity
• Word-length effect A set of monosyllabic words are
recalled more easily than a set of polysyllabic words
–
–
–
–
–
wit
sum
harm
bag
top
–
–
–
–
–
university
opportunity
aluminum
constitutional
auditorium
ST/Working Memory - Duration
• Information in STM decays rapidly without rehearsal
(Peterson,1959), between 15-20 seconds
– Ability to report novel consonant strings (TFDHG)
decreases if subjects are prevented from rehearsing (e.g.,
count backwards by 3 from 309)
– Correct responses reduced to below 10% after 18 seconds
Working Memory v. Atkinson and Shiffrin’s Short
Term Memory
• Baddeley and Hitch, 1974
• A limited capacity store for retaining information over a
period of seconds to minutes, and used for performing mental
operations. Information can be acted on and processed, not
merely maintained by rehearsal
– Sentence perception and comprehension
– Mental arithmetic
• Visual-spatial sketchpad and phonological loop
Long-term Memory
• In long-term memory
– Vast amounts of information may be stored for many
years. No known limits to capacity or duration of LTM
– Most information in LTM is encoded on the basis of
elaborative rehearsal
• Process of relating new information to information already stored
in memory
• Meaning (semantic encoding) is assigned to new information and
then linked to as much existing knowledge as possible
Types of Long-Term Memory
• Explicit (declarative) v. Implicit memory
– Semantic memory Memory for general facts and concepts
not linked to a specific time
– Episodic memory Memory for personal events in a specific
time and place
– Procedural memory & conditioned response
Types of Long-Term Memory
Explicit (declarative) v. Implicit memory
Rehearsal: Memory and Forgetting Curves
• Learning
usually
requires
rehearsal
(overlearning)
or
conscious repetition
• Ebbinghaus
studied
rehearsal by using
nonsense syllables: TUV
YOF
GEK
XOZ.
Introduced learning and
forgetting curves
• Concept of massed v.
distributed
practice
(spacing effect)
Memory Phenomena
• Serial Position Effect – Primacy and recency the first
and last items learned are most easily remembered
(Ebbinghaus)
More Memory Phenomena
• Autobiographical memory (Self-reference effect)
– Recollection of events in our life
– More recent events are easier to recall
• Extraordinary memory (super-memorists)
– Includes eidetic imagery (photographic memory)
– Usually due to well-developed memory
techniques
– Resource: The Brain: Teaching Modules
• Tip of the Tongue phenomena
Mood and Memory
• Context dependent memory
– Recall of information is better if environment is the same
as when information was learned. Examples?
• State-dependent memory
– Recall of information is better if person is in the same
physiological state as when information was learned
• Mood congruent memory
• Network theory
Biology of Memory
• Flashbulb memory Heightened emotions (stress-related or
otherwise) make for stronger memories, e.g. 9/11
– Early memories. Examples?
– Role of limbic system - amygdala
– However, continued stress may disrupt memory
– Scientific American Frontiers . Don't Forget. Watch Online
| PBS
Biology of Memory (and Learning)
• In Aplysia, Kandel (1982) showed that serotonin release
from neurons increased after conditioning
• Long-Term Potentiation (LTP) = enhancement of
synapses after learning (Lynch, 2002). Increases in
neurotransmitter release leads to strengthening of
synapses
• Where are memories stored?
– Different parts of the brain are specialized for
different types of memory information
– Primary role of hippocampus in forming
Where are Memories Stored?
Memory and Forgetting
• Decay Theory
– Memories deteriorate because of the passage of
time
• Amnesia
– Memory loss caused by accidents, surgery, poor
diet, or disease (dementia/Alzheimer’s)
– Retrograde and anterograde
– Psychogenic (v. organic) amnesia
– Scientific American Frontiers . Don't Forget. Resource: The
Brain: Teaching Modules
Memory and Forgetting
• After losing his hippocampus in surgery, patient
Henry M. (HM) remembered events before the
operation but could not make new memories.
Types of amnesia? Causes?
• Unkown White Male
– Scientific American Frontiers . Don't Forget.
– Resource: The Brain: Teaching Modules
Memory
The Story of Clive Wearing
• Accomplished musician
suffered a viral infection and
subsequent damage to his
brain
• His capacity to recall
autobiographic details as
well as general knowledge is
severely limited
Resource: The Mind: Teaching
Modules
The Story of Clive Wearing
• The hippocampus, the
structure we use for recall
and laying down new
thoughts, was profoundly
damaged due to infection
• Clive lost episodic memory,
that is, memory for events
• He can remember some
general information
(semantic memory)
Memory and Forgetting
• Infantile and Childhood Amnesia
– Generally poor memory for events prior to age 2-3
– Due to underdevelopment of brain structures
(hippocampus) and lack of cognitive abilities
– Role of language in memory?
Forgetting: Retroactive and Proactive
Interference
Retroactive Interference
occurs when new
information interferes with
information already in
memory
Proactive interference
occurs when information
already in memory
interferes with new
information
Memory and Forgetting
• Alzheimer’s Disease and Dementia
– Scientific American Frontiers . Don't Forget.
Resource: The Brain: Teaching Modules
(Re)Constructive Memory
• Reconstructive memory (Loftus)
– Memories can be altered with each retrieval
• Memory levelling and sharpening
– Memory is affected by one’s schema, prejudices,
experiences, suggestion, new information and/or
context
• Misinformation effect (confabulation)
• Misattribution (source amnesia)
– Elizabeth Loftus’ car crash and implanted
memories research
• Don't Forget.
• Loftus’ Curriculum Vitae
(Re)Constructive Memory and Eyewitness
Testimony
• Eyewitness testimony (Loftus)
– Shown to be unreliable
– People’s recall for events may be influenced by what they
heard or imagined (e.g. post-event information)
– Role of schema
Repressed Memory
• Recovered memories (Repressed memory or Motivated
Forgetting)
– Involves the recall of long-forgotten dramatic events
– May also be the result of suggestion, post-event
information, imagination inflation (False Repressed
Memory Syndrome)
– More recent research supports that some memories can
be repressed and recalled later. It remains controversial