The Human Information Processing System
Since, the late 1960’s, cognitive psychologists have drawn parallels between computers and human thought, as both is involved
in the manipulation of information.
The modal model of memory which dominated the 1970’s and 80’s is the multi-memory component information processing
system of Atkinson and Shiffrin (1968, 1971)
3 memory components of the Atkinson & Shiffrin Model of Human Memory :
Sensory Memory : Analogous to keyboard or scanner, or voice recognition system
Short Term Memory : Analogous to the CPU
Long Term Memory : ROM storage where software is stored
Sensory Memory Systems
Sensory memory is responsible for the encoding of information.
Encode : to take in information and convert it to a usable mental form.
Sensory memory systems are responsible for transforming environmental input into neural impulses which the Short Term
Memory system can process.
There is a different sensory memory system for every human sense: tactile, olfactory, gustatory, auditory, and visual.
Cognitive Psychologists have focused primarily on auditory and visual sensory stores.
Sensory Memory systems are typically discussed with respect to attention, capacity and duration.
Auditory Sensory Memory
Echoic Memory (Neisser, 67) ; is the sensory memory component which receives auditory stimulation from the external
environment.
Attentional Aspects of Echoic Memory : All auditory information above threshold (loud enough to be heard) is processed by the
auditory sensory memory to a certain degree.
1, Attention helps us to filter out irrelevant auditory stimuli -à Talking to an individual in a crowded or noisy room.
However, the irrelevant information is still partially processed, as evidenced by the ‘cocktail party phenomenon’
The cocktail party phenomenon
Cherry (’58) : Helped develop the ‘shadowing task’
In a shadowing task, the participant is wearing earphones and is told to ‘attend’ one auditory signal while ignoring a second
auditory signal.
Shadowing is when the participant has to repeat back (aloud) whatever message they are paying attention to.
When participants fail to shadow the attended message, or repeat back the message from the ignored ear, this is evidence that
even ignored information is processed to some degree.
The ‘cocktail party phenomenon’ refers to the particular environmental sensitivity we have to the auditory pattern which
represents our name.
Our name being mentioned captures our attention, and shifts processing from the attended ear to the ignored ear.
Other Aspects of Auditory Sensory Memory
Processing auditory information is largely automatic: as long as the auditory signal is loud enough, the signal will be passed on to
short term memory system.
Echoic Memory lasts about 2 ½ seconds, making it the longest lasting sensory memory store.
The echoic memory system holds information longer than the actual physical duration of the stimulus, important because
auditory information is spread across time.
Echoic memory helps to account for the recency effect seen in immediately remembering auditorily presented information.
Echoic Memory represents raw auditory information, and does not process the auditory signal, only converts it to usable mental
data for the Short Term Memory system to process.
Visual Sensory Memory
Iconic Memory (Neisser, ’67) : the brief duration sensory memory store designed to receive and hold visual information.
Iconic Memory has a very large capacity : All of the visual information in a scene is processed, even though only a limited
amount of information can be remembered form a specific icon.
Iconic Memory is very short in duration, lasting only about 250 to 500 ms.
The short duration of an icon is why we cannot remember every single detail of a visual icon, because only a limited amount of
information can be quickly passed to short term memory.
The short duration of the icon has important evolutionary advantages.
Short Term Memory / Working Memory
Short Term Memory : the memory buffer that holds currently and recently processed information, and the can manipulate that
information as well.
Short Term Memory can hold information passed to it from the sensory register and from long term memory.
Working memory refers to the mental processing of currently active information.
Short Term Memory capacity varies from 5 to 9 pieces of information.
Miller (1956) the magic number 7 + or - 2
Humans can get around this limited capacity of short term memory by chunking related pieces of information together.
The availability heuristic is partially due to short term memory capacity limitations.
Working Memory refers more specifically to the mental scratch pad which allows us to transform information currently available
in short term memory.
The limitation in working memory is due to processing allocation limitation.
How many tasks can you perform at one time?
Walking and Chewing Gum requires more processing resources than walking alone.
Cell Phone Use and Driving , a dangerous behavior due to processing limitations.
Processing of information in short term memory also allows us to store the results of our information processing in long term
memory for later retrieval and usage.
Two common ways of holding information in short term memory and passing it on to long term memory :
Maintenance Rehearsal : Effective for holding information in short term memory, but not very effective for transferring
information into long term memory. Endless repetition of a phone number until you dial it is one example of maintenance
rehearsal
Elaborative Rehearsal : Much more effective for transferring information into long term memory. Elaborative rehearsal
involves finding or creating an association between information in short term memory and information previously stored in long
term memory.
The difference in the effectiveness of these rehearsal strategies is sometimes referred to as a depth of processing effect. (Craik
& Lockhart, ’72)
Long Term Memory
The mental storage system responsible for storing information on a relatively permanent basis.
Long Term Memory is assumed to be unlimited in capacity for all practical purposes.
The phrase "You can’t teach an old dog new tricks" does not refer to a long term memory capacity limitation.
The duration of long term memory is assumed to be permanent….. forgetting is most often characterized as a retreival failure,
rather than the idea that the information disappears from the mind.
Oftentimes, the learning of new information can interfere with the recall of older, related information (retroactive interference),
and
older information can interfere with our ability to learn new information (proactive interference)
Seven Modern Areas of Investigation
1.Attention
2.Automatic and Strategic Processing
3.Bottom-up vs. Top-down Processing
4.Representation of Knowledge
5.Metacognition
6.Nonconscious or Unconscious Processing
7.Levels of Analysis
Attention
A fundamental topic in cognitive psychology
Attention is responsible for:
a. transferring information between memory systems
b. controlling the processing of information in working memory.
Human beings are assumed to have only a finite amount of attentional resources available to them at any one time.
Attention is sometimes referred to as the executive controller in models of mental processing.
Executive controller : The mental structure charge of allocating attentional resources.
Automatic and Strategic Processing
Due to our amazing capacity for learning we can often overcome processing limitations by making behaviors so automatic that
they do not require conscious processing.
For example, you have no choice but to read and comprehend this sentence.
Why ? Because processing visual information known as writing and translating the visual input into meaningful concepts has
become automotized since the age of two or three.
Hooked on Phonics : Sounding out words, a very strategic and deliberate way to learn phoneme combination.
Other automatized behavior :
Walking
Processing auditory language information
Tying your shoes
Buttoning buttons
As a particular behavior changes from being completely conscious and strategic to automatic, the attentional resources required
to complete that behavior become significantly reduced.
When you have two or more highly automated behaviors, you can engage in parallel processing, performing both behavior
simultaneously.
When you are trying to perform two strategic behaviors, you must frequently stick with sequential processing.
Sometimes, our short term memory retrieves information so automatically from
long term memory we have little conscious awareness of our thought process.
Fast Process Tasks : tasks which rely on highly practiced
mental processes show little conscious involvement.
Slow Process Tasks : Take from several seconds or more
and rely heavily on conscious resources. (Eysenck, ’82)
Data Driven (Bottom- Up) vs. Conceptually Driven
(Top-Down) Processing.
Is your behavior driven by your sensory perceptions of the
immediate environment or is it driven by all of your past
experiences in similar situations ?
The more experience we have with a particular situation, the
more we will let prior experience and behavior guide our
current actions.
Golfing and Skiing are two sports which can illustrate the
distinction between automatic and controlled processing and
bottom-up vs. top-down processing.
Representation of Knowledge
How is knowledge represented in the Brain ?
For example, think of the word chair
You can recognize this visual pattern of letters,
You can recognize the auditory pattern associated with this
stimulus.
You can conjure up a mental image of what this stimulus
looks like.
You can probably remember specific chair related stories
as well.
Visual, verbal, auditory, and autobiographical information is
all stored in long term memory and ready to be recalled
when you see this stimulus in some form.
Distinctions in memory and knowledge types
Tulving (’72) distinguishes between two memory types,
Episodic and Semantic.
Episodic Memory : Your autobiographical memories.
Semantic Memory : contains a person’s general world
knowledge, including knowledge of language.
People with psychogenic amnesia have difficulties retrieving
episodic memories, while their semantic memories remain
largely intact.
Anderson (’76) identified two differences in types of
knowledge :
Declarative Knowledge : basic facts and conceptual
knowledge.
Beets are Red
Andrew Johnson was the 17th president.
Procedural Knowledge : Knowing how to do something :
Tying your shoes
Arithmetic Problems
Sometimes, because our procedural knowledge becomes so
automatic, it is difficult to verbalize the specific steps we go
through when completing a highly automatic procedure.
Metacognition
Awareness and monitoring of one’s own cognitive state or
condition.
Thinking about your own thoughts
Metacognition is expressed through our adoption of specific
strategies in specific situations.
How we rehearse information (maintenance vs. elaborative)
is influenced by our metacognitive abilities.
Our ability to learn better ways of learning is reflective of our
metacognitive abilities.
Nonconscious or Unconscious Processing
Mental processing that occurs without conscious awareness.
Tip of the tongue phenomenon (aphasia) : You fail to recall
somebody’s name, forget about the incidence, and two to
three days later their name just "pops" into your head (enters
conscious awareness) without you even thinking of the prior
incidence.
The cognitive abilities are considered to be unconscious
merely because we are not aware of the mental processing
taking place, as when performing "fast process tasks".
Implicit Memory : Learning is, to a certain degree, automatic.
If I have you read a paragraph, don’t tell you that I am going
to test you in some way on the passage, you will still show
some recall of the passage even if you never consciously
attempted to transfer the information into long term memory.
Levels of Analysis in Cognitive Science
As the different branches of psychology evolve, there
becomes more and more cross pollination of theories and
concepts. Cognitive Psychologists are more aware today
than ever of the contributions to cognitive psychology which
can come from a wide variety of disciplines, including social
psychology, abnormal psychology, biopsychology, and
neurology, to name a few.
Connectionist Modeling: A parallel distributed processing
model of cognitive performance, draws heavily from
biopsychology and neurology. This is a model that has
moved substantially away from the "boxology’ explicit in the
Atkinson & Schiffrin’s model of the mind.
Cognitive psychologists focus on individual similarities in
cognitive processing of normal individuals, and can contrast
that with processing of specific clinical populations in order
to gain a more complete understanding of the healthy mind,
as well as how the healthy mind can break down.