Human Memory

1
Human Memory

• Doneisha Burke M.Sc.

2
Human Memory

• What would life be like without memory?
• Memory is defined as our cognitive system (s) for
  storing and retrieving information.
• Two very influential models of human memory have
  been put forward
• The Atkinson Shiffrin Model
• Neural Network Models

3
The Atkinson Shiffrin Model

• Many researchers have found computer memory to be
  a useful working model of memory and as such it
  was the basis on which Atkinson and Shiffrin
  proposed their model of memory which linked the
  study of human memory firmly to the
  Information-Processing Perspective.
• According to them human and computer memory must
  accomplish 3 basic tasks
• Encoding, Storage Retrieval

4
(No Transcript)
5
The Atkinson Shiffrin Model

• The model identifies 3 distinct systems for
  storing memory
• Sensory Memory
• Provides temporary storage of information
  delivered by our senses
• Short-Term Memory
• Holds relatively small amounts of info for 30
  secs. or lt
• Long-Term Memory
• Retains large amount of information over long
  periods of time

6
The Atkinson Shiffrin Model

• Active control processes which filter
  information, help in moving information from
  sensory memory to short-term memory.
• Selective attention helps us to pay attention to
  some aspects of the world while largely ignoring
  others.
• Elaborative rehearsal (when we think about its
  meaning and relate to other info. stored in LTM)
  is what moves information from STM LTM
• Simply repeating information is not as effective
  as attaching meaning to it when it comes to
  storing info in LTM

7
Neural Network Models

• Model of memory that describe parallel
  (simultaneous) processing of information by
  numerous neural modules in the brain, each of
  these processing units is dedicated to a specific
  task and all are interconnected.
• The information is processed by many neural
  modules, each of which is dedicated to a specific
  task. Parallel processing therefore greatly
  enhances the speed and efficiency of memory

8
Human Memory The kinds of information stored

• Memory holds several kinds of information ranging
  from factual knowledge to general knowledge
• Working Memory (WM- sometimes referred to as
  Short Term Memory) involves both the storage
  capacity and capacity to process/transform
  information held in this memory system
• The Serial Position Curve provides answer as to
  whether or not WM exist
• Greater accuracy for information early and late
  in a list of information than in the middle of a
  list.

9
Working Memory

• How much it can hold?
• Short Term Memory (WM) as a storage system can
  hold 7 (plus/minus 2) discrete items, beyond that
  leads to overload and information being
  forgotten.
• The process of chunking does increase WM capacity
  quite significantly even though it can only
  retain 7-9 separate items at once.
• The Multiple Components Model of Working Memory
  suggests that it includes a phological loop,
  visuospatial sketch pad and central executive

10
Memory for Factual Information

• Memory of this sort is also known as explicit or
  declarative memory because we can bring into
  consciousness and verbally report it.
• It consists of 2 major parts
• Episodic memory
• Memory for factual information we acquired at a
  certain time/place
• Semantic memory
• Holds memory of a general nature which we do not
  remember acquiring at a certain time/place

11
Memory for Factual Information

• Factors that affect episodic memory include
• Amount and spacing of practice, kind/level of
  processing performed, retrieval cues/ context
  dependent memory and our internal/physical state
  (state dependent retrieval)

12
Memory for Factual Information

• Semantic Memory
• Focus is on organization and this is aided by
  Concepts mental categories for objects/ events
  that are similar to one another in certain ways
• The meaning attached to concepts is related to
  prototypes (idealized representations) and
  exemplars ( an e.g. of a category of things
  readily brought to mind)

13
Memory for Skills Procedural Memory

• Procedural memory (Implicit Memory)- memory
  system that retains information we cannot readily
  express verbally (e.g. information necessary to
  perform skilled motor activities)
• Priming helps explain how we are able to
  recognize information later after having seen or
  heard a stimulus only once before, even if we are
  unaware of this effect (automatic priming

14
Forgetting

• Forgetting has more to do with just the passage
  of time.
• Interference, which occurs in 2 different forms
  offers an explanation
• Retroactive
• When information currently being learned
  interferes with information already present in
  memory
• Proactive
• When information already present in LTM
  interferes with the acquisition of new memory

15
What happens to information once it is stored?

• Permanent
• Forgotten
• Distorted
• It involves schemas, motives, and source
  monitoring (process of identifying the origin of
  specific memories) reality monitoring (the
  process of deciding whether specific memories are
  based on external or internal sources).

16
Memory Construction

• Recalling events that did not actually occur or
  experiences one never really had
• Eyewitness testimony
• Factors that reduce accuracy of eyewitness
  testimony include
• Suggestibility
• Source monitoring
• Illusion of out-group homogeneity
• Enhancing eyewitness testimony

17
Memory in Everyday Life

• Repression
• The active elimination from consciousness of
  memories of experiences we find threatening.
• Autobiographical memory
• Memory for information about events in our own
  lives.
• Infantile Amnesia
• Our supposed inability to remember experiences
  during the 1st 2/3 yrs of life.

18
Memory in Everyday Life

• Memory for emotionally laden events
• Flashbulb memories
• Vivid memories of what we were doing at the time
  of an emotion provoking event
• Effects of mood on memory
• Mood-Dependent Memory
• An enhanced ability to when we are in a given
  mood to remember what we learned when previously
  in that same mood
• Mood Congruence Effects
• Tendency to remember information congruent with
  our current mood

19
Memory and the Brain Amnesia and other Memory
Disorders

• Amnesia- loss of memory stemming from illness,
  injury, drug abuse, or other causes.
• 2 major types exist (pg 237)
• Anterograde Amnesia- the inability to store into
  LTM information that occurs after an amnesia
  inducing event
• Retrograde Amnesia- loss of memory for events
  that occurred prior to an amnesia inducing event
• Amnesia and Korsakoffs Syndrome
• Illness caused by long term abuse to alcohol,
  often involving profound retrograde amnesia (note
  well effects on body/brain and memory pg 239)

20
Memory and the Brain Amnesia and other Memory
Disorders

• Alzheimer's Disease
• Occurs in 5 of all ppl. over age 65
• Begins with mild problems such as inability to
  remember names, numbers etc. moves onto inability
  to dress groom oneself and almost complete
  memory loss
• Semantic memory, working memory, autobiographical
  memory etc. are all disturbed.
• Studies of the brain show that in most cases they
  contain tangles of amyloid beta protein (pg 239)
• Role of acetylcholine (neurotransmitter) in
  Alzheimer's

21
Memory and the Brain A modern View

• Several major conclusions exist (pg 239)
• Localization of memory functions- Role of the
  hippocampus and the frontal and temporal lobes
• Damage to various brain structures leading to
  amnesia and other memory deficits
• Memory Trace