Sensory and shortterm memory'

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Sensory and short-term memory.

• Meredith McKague
• HP502 Week 8.
• Email m.mckague_at_ballarat.edu.au
• Phone [phone].
• Room H206.

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Memory The story of Clive Wearing.

• A professional broadcaster and musician who
  suffered encephalitis and subsequent damage to
  his brain.
• Capacity to recall autobiographic details and
  recall of general knowledge poor.
• Musical ability preserved.

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The story of Clive Wearing.

• The following extracts are from Deborah Wearing
  (2005). 'Forever Today A Memoir of Love and
  Amnesia', (Doubleday)
• A virus had caused holes in Clive's brain his
  memories had fallen out. It was encephalitis,
  from herpes simplex, the cold-sore virus. The
  virus lies dormant in most of the population.
• Occasionally, instead of going to the mouth it
  goes to the brain. The brain swells up, and,
  before long, brain crushes against bone.
• The part it wipes out completely is the
  hippocampus.
• These structures are what we use for recall and
  remembering, and laying down new thoughts.

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The story of Clive Wearing.

• Clive was constantly surrounded by strangers in
  a strange place, with no knowledge of where he
  was or what had happened to him.
• To catch sight of me (his wife) was always a
  massive relief. Every time he saw me, he would
  run to me, fall on me, sobbing, clinging. It was
  a fierce reunion.
• "I thought I was dead," he would say, "if I had
  any thoughts at all."
• If I left Clive's side, the impact of my
  reappearance after a trip to the bathroom, a word
  with a nurse, was no less than at my first
  appearance that day.

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The story of Clive Wearing.

• In spite of Clive's amnesia, he retained his
  fundamental intelligence. That was what made his
  condition all the more horrific.
• Clive no longer had any episodic memory, that is,
  memory for events.
• Clive did not have the brain parts necessary to
  recall anything that had happened to him in the
  whole of his life.
• But, he could remember general things (semantic
  memory).
• For example, Clive knew that he was married
  (semantic), although he was unable to recall our
  wedding (episodic) - a civil ceremony in Camden
  Town Hall in September, 1983.

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The story of Clive Wearing.

• I was soon to discover that more of Clive's
  brain was intact.
• I picked up some music and held it open for Clive
  to see. I started to sing one of the lines. He
  picked up the tenor line and sang with me. A bar
  or so in, I suddenly realised what was happening.
  He could still read music. He was singing. His
  brain was still capable of music.

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The story of Clive Wearing.

• This (music) opened a door for Clive. He could
  sit down at the chapel organ and play with both
  hands on the keyboard, changing stops, and with
  his feet on the pedals, as if this were easier
  than riding a bicycle. Singing was in many ways
  easier than talking. It transcended language
  (procedural/implicit memory).
• And the momentum of the music carried Clive from
  bar to bar. He knew exactly where he was because
  in every phrase there is context implied by
  rhythm, key, melody. When the music stopped,
  Clive fell through to the lost place. But for
  those moments he was playing he seemed normal
  again.
• Deborah Wearing 2005. 'Forever Today A Memoir
  of Love and Amnesia', by Deborah Wearing
  (Doubleday)

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Learning and memory.

• 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 (Squire, 1987) .

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Memory.

• Memory is the outcome of learning.
• Learning happens when a memory is created or is
  strengthened by repetition.

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Memory stages Encoding.

• Encoding the processing of incoming information
  to be stored.
• Includes acquisition and consolidation.
• Acquisition registers inputs in temporary sensory
  storage.
• Consolidation creates a stronger representation
  over time.

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Memory Stages Storage.

• The result of acquisition and consolidation is
  storage.
• The maintenance of a permanent record to be used
  at a later time.

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Memory stages Retrieval

• Retrieval
• The utilisation of stored information to create
  a conscious representation, or to execute a
  learned behaviour like a motor act.
• The process of recovering information stored in
  memory so that we are consciously aware of it.

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The Stage Model of memory.

• Atkinson and Shiffrin, 1968.
• Memory consists of three stages based on how long
  memory is retained (duration), and how much can
  be stored (capacity).
• Sensory memory
• Short-term memory (working memory).
• Long-term memory.

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The Stage Model of memory.

• Sensory memory
• duration is milliseconds-seconds.
• capacity is large.
• Short-term memory
• duration is seconds to minutes
• capacity is limited.
• Long-term memory
• duration is days to years.
• capacity is large

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Stage model of memory
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Sensory Memory.

• A sensory-based temporary representation of input
  through sensory channels.
• Iconic (visual) and Echoic (auditory) memory.
• Decays quickly
• Large capacity (relative to STM).

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Sensory memory Iconic store.

• Sperling (1960) determined the capacity and
  duration of the iconic store with a series of
  ingenious experiments.
• Full versus partial report method.

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Sensory memory Iconic memory Full report.
H B R T J K E Q A C Y L
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Sensory memory Iconic memory Partial report.
H B R T J K E Q A C Y L
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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 being read out from a rapidly
  decaying icon.

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Sensory memory Iconic memory.

• By varying the onset of the cue, Sperry also
  determined the duration of iconic memory.
• The advantage from cueing gradually declined and
  disappeared after 500 ms.

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Sensory memoryEchoic store.

• Experiments performed in the auditory domain
  suggest a similar modality specific memory store
  for sounds known as echoic memory.

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Sensory memoryEchoic store..

• Experiment (Moray 1965)
• Simultaneously presented sequences of consonants
  from four different locations
• When cued to recall one location the estimated
  total amount of material stored was greater than
  when Full Recall was requested
• Same as Sperling

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Sensory memoryEchoic store.

• The duration of the echo is 3-4 seconds.
• Information held in iconic or echoic form is
  susceptible to masking by stimuli presented
  immediately afterwards.

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Sensory memoryEchoic store.

• Echoic memory is similar to Iconic memory in that
  there is more information accessible than can be
  recalled.
• Echoic memory is different in that the trace
  lasts longer.

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Sensory memory

• Sensory memory prolongs briefly presented stimuli
  to increase the chance that they will be present
  long enough to be attended.
• Also allows stream of consciousness, rather
  than a series of disconnected images and sounds.
• Attended information then transferred to
  short-term store where it can be held for a
  matter of seconds and can be integrated with
  information from other sources.
• From STM information can be stored in long-term
  memory in the form of a multi-dimensional memory
  trace.

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Sensory memory

• Physiological studies using ERP (event-related
  potentials) have demonstrated that sensory
  memories are stored in sensory-specific cortex
  areas as short-lived neural traces.
• For example, the echoic memory trace is stored in
  the auditory cortex on the supra-temporal plane.

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Short-term Memory.

• STM is capacity limited.
• Duration is seconds to minutes.
• Available to consciousness.

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Short-term memory.

• The part of memory where information from sensory
  memory and long-term memory are made conscious.
• A limited capacity temporary store for retaining
  information over a period of seconds

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Short-term memory.

• Information maintained in STM via rehearsal.
• Without rehearsal there is a rapid decay.
• Maintenance rehearsal e.g., repeating an
  unfamiliar phone number until you dial it.

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Short-term memory Capacity

• George Miller (1956) demonstrated that short term
  memory capacity is about seven (plus or minus
  two) units of information.
• STM can hold as much information as can be
  repeated or rehearsed in 1.5 to 2 seconds.

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Short-term memory Capacity

• Short-term memory capacity often assessed using a
  digit-span task.
• Random digits presented, list gets increasingly
  longer to determine your capacity.

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Short-term memory Capacity.

• Evidence for a time limit on STM
• The word-length effect
• 5 monosyllabic words recalled more easily than 5
  polysyllabic words.
• wit sum harm bag top
• Recall?
• university opportunity aluminium constitutional
  auditorium
• Recall?

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Increasing the capacity of STM.

• Chunking
• The grouping of information into meaningful
  units.
• Chunking can increase the amount of information
  contained in STM.

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Increasing the capacity of STM.

• Example of chunking.
• Test your ability to recall the following
  sequence of letters.
• TJYFAVMCFKIB
• Recall?
• Now try and recall the same sequence when it is
  chunked into meaningful units
• TV FBI JFK YMCA
• Recall?

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Short-term memory

• Information in STM decays rapidly without
  rehearsal (Peterson and Peterson,1959).
• Ability to report novel consonant strings (XPL)
  decreases if subjects are prevented from
  rehearsing.
• Subjects perform mental arithmetic (e.g., count
  backwards by three from 309).
• Correct responses reduced to below 10 after 18
  seconds

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Short-term memory

• Rehearsal in STM also considered critical in
  transfer of information to LTM.
• STM and LTM as separate mechanisms with rehearsal
  mediating the transfer between them.

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Working memory

• Baddeley and Hitch, 1974.
• A limited capacity store for retaining
  information over a period of seconds to minutes,
  and for performing mental operations on the
  contents of this store.
• Information can be acted on and processed, not
  merely maintained by rehearsal.
• Sentence perception and comprehension.
• Mental arithmetic.

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Working memory

• A central executive (attentional) system presides
  over the interactions between two subordinate
  systems
• The phonlogical loop.
• The visuospatial sketch pad.
• Both sub-ordinate systems provide modality
  specific mechanisms for rehearsal and mental
  operations.

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Baddeleys model of working memory.
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Working memory The Phonological Loop

• Phonological loop utilises sound-based codes for
  representing information in working memory.

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Working memory The Phonological Loop

• The Phonological Similarity Effect
• (GPVT harder than RHXK)
• The unattended Speech Effect
• (speech-based sounds disrupts speech-based tasks)
  
• The Word-Length Effect
• (More monosyllabic than polysyllable words
  remembered)

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Working memory The Phonological Loop

• Baddeley believes that language comprehension and
  acquisition are dependent on the phonological
  loop
• Individuals with impaired working-memory have
  difficulty learning new words.

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Working memory The visuo-spatial sketchpad.

• The visuo-spatial working memory system
  temporarily holds visually based representations
  such as faces, objects, and written words.
• Enables the manipulation of visually represented
  information.
• mental rotation of objects
• the use of visual mnemonics
• mental arithmetic.

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Working memory

• The visuospatial sketch pad is independent of the
  phonological loop.
• If subjects asked to perform a visuospatial task
  while trying to recall a list of words, there is
  no interference.
• For example Visuospatial task Recall the
  sequence in which a series of blocks were
  touched.
• Does not interfere with a speech based memory task

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Working memory

• Neuropsychological evidence.
• Damage to discrete parts of the brain demonstrate
  a dissociation between the phonological loop and
  the visuospatial sketchpad.
• The phonological loop is located in a
  left-hemisphere parietal lobe network.
• The visuospatial sketchpad is compromised by
  damage to the right parieto-occipital region.

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Working memory The Central Executive.

• The central executive presides over the
  operations of working memory. It is the
  processor that allocates resources, governs
  attentional processes, and adjusts goal
  priorities moment by moment.
• (Jonides, 1995)
• Control functions are strongly associated with
  activity in the frontal lobes.

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Working memory Central Executive.

• The Central Executive is a limited capacity
  attentional system that controls the phonological
  loop and the sketch pad and relates them to
  information from long-term memory.

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Working memory Central Executive.

• The Central Executive plans and coordinates
  complex behavior
• Goal orientation
• Focus attention

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Working memory Central Executive.

• The ability to form a coherent plan (fluid
  intelligence) is compromised after damage to the
  prefrontal lobe of the frontal cortex.
• General memory and crystallised intelligence are
  not affected by damage to the prefrontal lobe.

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Working memory Central Executive.

• Frontal lobe patients find it difficult to carry
  out a plan.
• For example Go shopping, then keep an
  appointment at a given time, and then collect
  four pieces of information.

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Working memory Central Executive.

• The Central Executive is not a memory system.
• The Central Executive coordinates subsystems
  (phonological sketchpad)
• Incorporates all memory information.
• Allocates attention to complete tasks.