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 multi-store 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 known as phonological similarity effect

• 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….– F D R T V F B I J F K C I A

– 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