Transcript Cognition and Information processing

Cognition and Information
processing
G.Affleck
• A major influence on the view of
knowledge and information presentation
has come from cognitive psychology.
• Cognitive psychologists theorise about the
covert structures that behaviourists ignore
Such as the complexities of memory structure
and capacity, types of memories, nature of the
stored knowledge and transfer of knowledge.
The capacity of Short-term memory
• The capacity of working memory has been
the subject of much research. How are
experts seemingly able to hold more
information, perform more tasks, all with
an apparent ease, which is lost to the
novice?
Chunking
• The idea of cognitive load and chunking,
based on Miller’s (1956) theory, is that we
can think of between 5 and 9 items at a
time in our consciousness, but that
through a process of learning and
familiarisation tasks that once took up full
working memory (i.e. 5-9 items) become
chunked and need less working memory
• For example, when learning how to drive,
all concentration is needed to begin with,
and even then the task is so overwhelming
that we need the support of an instructor
• We have much to think about that would
occupy a chunk of working memory:
– the clutch,
– brake,
– mirrors,
– steering wheel
– and much more including other traffic.
• However, with practice the task of driving
no longer takes up our entire processing
power.
– we are able to drive,
– listen to music,
– look at the scenery,
– and carry on a conversation
all at the same time.
Task
Sub-tasks each take up 1
chunk of working memory.
gears
clutch
mirror
Eventually the overall task becomes chunked and
requires only 1 unit of working memory. This once
overwhelming task can then become a subtask in a more
complex overall task.
The chunked knowledge of
performing the task may now
transfer.
Becomes 1 chunk within a task of
greater complexity.
Formula 1 racing
Driving
Long-Term Structure
• Long-term memory is characterised by cognitive
psychologists as being relatively stable and
structured.
• The structure of LTM has been the subject of
much research and debate. In the early 1980’s
schema theory became the dominant theory
used to explain memory structures and
differences between novices and experts in
problem- solving skills (Sweller & Chandler,
1991).
According to Rummelhart (1989) long-term
memory consists of schemata which are
higher-level metaphorical sets of
associations which provide knowledge
frameworks.
With chunking the sets of associations will
lead to qualitatively deeper understanding.
Building Knowledge
• Distinction has also been made between
types of knowledge that will be
constructed in short-term memory and
transferred to long-term memory.
– Episodic
– Semantic
• Episodic memory is the recollection of a
particular experience and semantic
memory is the residue of many past
episodic memories with access to this
based on generic commonalities
(Tulving, 1972).
Episodic x
Episodic x
semantic
Episodic x
• Transfer Semantic - Episodic
– Similarities and dissimilarities are recognised
between episodes and the situational episode
will both inform and be informed by the
semantic knowledge.
Episodic x
Episodic x
Episodic x
semantic
Episodic x
Episodic x
• Eventually a situation is well known and enough
semantic knowledge is built up that will adequately
inform the situation with little conscious thought.
Knowledge is chunked, and eventually tasks may be
completed with seemingly little conscious thought as if
automated.
semantic
Episodic x
Episodic x
Explicit and Implicit Knowledge
• Graf and Schacter (1985) offer a definition
of explicit and implicit memory in the
following way:
“Implicit memory is revealed when performance
on a task is facilitated in the absence of
conscious recollection; explicit memory is
revealed when performance on a task requires
conscious recollection of previous experiences.”
• Traditional measures of memory such as
free recall, cued recall and recognition all
involve the use of direct instructions to
retrieve information about specific
experiences, and are therefore measures
of explicit memory. (Eysenck and Keane
P.193)
• Explicit memory is that which can be easily
made verbal such as declarative
knowledge (Graf and Schacter, 1985).
• Implicit memory is that which cannot be
easily made verbal such as procedural
knowledge (Graf and Schacter, 1985)
• Episodic knowledge is therefore the holistic
knowledge consisting of implicit, procedural,
explicit and declarative knowledge built in the
context of such as a situation, experience,
problem or exercise, all under the umbrella term
episodic.
• Semantic knowledge becomes the residue,
which will include such implicit knowledge.
Cognitive load theory
• stems from the proposition that we have a
substantial long - term memory and a
relatively poor working memory. Cognitive
load theory proposes that high levels of
cognitive load consume working memory
and inhibit the creation of schemata in
long term memory.
proposed by Sweller (1988)
• “The theory suggests that many commonly used
instructional procedures are ineffective because
they ignore information processing limitations”
Sweller (1993, p.8).
• Transfer between short term and long- term
memory is not automatic, with such as cognitive
load affecting the amount of information that a
person is able to process at a given time.
• Thus optimal learning will depend on not
overloading working/short-term memory.
• Cognitive load theory suggests that
reducing the cognitive load associated
with constructing a representation
facilitates learning (Sweller & Chandler, 1991).
Novice/Expert
• Is it the case that difficult subjects like
computer programming have little
declarative knowledge but lots of implicit
knowledge, knowledge that an instructor
cannot make explicit?
• What would the experts knowledge consist
of?
Through the building of episodic and semantic
knowledge (via episodic)
the expert programmers domain of knowledge
becomes a complex web of implicit procedural
and explicit declarative knowledge, a domain
specific framework
Schema, frames, scripts
The semantic knowledge may then be applied to the
current situation
Current Situation
The expert has many solutions/patterns already
constructed (Kahney, 1994)
The expert has deep level knowledge of the
structures of the concepts of a domain and can
relate it to prior experience and knowledge.
Familiar patterns give seemingly instant solutions
• In summary short-term memory holds the information of
a particular instance of time, a situation/sense
impression.
• Prior knowledge built from semantic knowledge informed
by episodic knowledge consisting of explicit/implicit and
procedural /declarative knowledge is used to understand
the given situation thus creating a mental model of the
situation.
• The mental model of a situation in turn can become a
new episode (sense impression stimulus) that will inform
the schemata in long-term memory.
How is a response generated?
input
output
STM: Mental Model
Schema , script, frame.
Response
to output
becomes an
episode
which may
inform 1 or
more
schemata
situation
Sense impressions
semantic
Prior
knowledge
Generalised
Assimilation
semantic
Transfer
e.g. analogy
LTM
episodic
episodic
Schema X
Schema Y
Explicit declarative
knowledge
Implicit procedural
knowledge
Competence/expertise
through saturated semantic
knowledge