Transcript Schema theory ppt

Schema Theory
Learning Outcomes (from the IB Syllabus)
Evaluate schema
theory with reference
to research studies
What is schema
theory ?
Schema Theory
What is a Schema?
“A mental model or representation built
up through experience about a person,
an object, a situation, or an event.”
(Head, 1920)
“Organised structures of knowledge
and expectations of some aspect of the
world.” (Bartlett, 1932)
Schema of an “egg”
What is a schema ?
Schema theory seeks to explain our interpretation of
the world from a psychological perspective, which
stems from cognitive science.
Schemas (or schemata) are cognitive structures
(mental templates or frames) that represent a
person's knowledge about objects, people or
situations.
Schemas are derived from prior experience and
knowledge. They simplify reality, setting up
expectations about what is probable in relation to
particular social and textual contexts.
What is a schema ?
Schemas are used to organise our knowledge, to
assist recall, to guide our behaviour, to predict likely
happenings and to help us to make sense of current
experiences.
Schema theory predicts that we interpret our
experiences by using relevant social and textual
schemas. Bartlett (1932) described how schemata
influence memory in his research with 'Story of the
ghosts'.
A schema can be seen as a kind of framework with
'slots' for 'variables', some of them filled-in and
others empty.
What is a schema ?
Schema theory predicts that we interpret our
experiences The slots are either filled in already with
compulsory values (e.g. that a dog is an animal) or
'default values' (e.g. that a dog has four legs) or are
empty (optional variables) until ' instantiated' with
values from the current situation (e.g. that the dog's
colour is black).
When what seems like the most appropriate schema
is activated, inferences are generated to fill in any
necessary but inexplicit details with assumed values
from the schema.
If no relevant schema is retrieved from long-term
memory a new schema is created. Explicit events
and inferences, as well as new schemas, are stored
in long-tern memory.
Schema-driven processing is a top-down perceptual
process that guides a selective search for data
relevant to the expectations set up by the schema.
Schema-driven processing interacts with bottomup data-driven processes (which may lead to the
activation, modification or generation of a schema).
Schema theory is consistent with the
notion of both perception and recall as
constructive and selective cognitive
processes.
Schemas are culturally specific: schemas
for common routines vary socioculturally- even within a single country.
War of the Ghosts (1932)
This was an unusual story for people from a
Western culture to understand because it
contained unfamiliar supernatural concepts
and an odd, causal structure.
After an interval participants were asked to
recall as much of the story as possible.
methodology
Serial reproduction – participant reads and recalls
the story, second person reads and recalls the second
reproduction…….and so on
Repeated reproduction – partipants reads the story
and repeats it over various recall intervals
The War of the Ghosts
http://cla.calpoly.edu/~dlvalenc/PSY307/LINKS/GHOSTWAR.HTM
One night two young men from Egulac went down to the river to hunt seals, and while they were it
became foggy and calm. Then they heard war cries and they thought; 'Maybe this is a war-party.'
They escaped to the shore, and hid behind a log.
Now canoes came up, and they heard the noise of paddles and saw one canoe coming up to them.
There were five men in the canoe and they said; 'What do you think? We wish to take you along. We
are going up the river to make war on the people.'
One of the young men said; 'I have no arrows.'
'Arrows are in the canoe,' they said.
'I will not go along. I might be killed. My relatives do not know where I have gone. But you,' he said,
turning to the other, 'May go with them.'
So one of the young men went, but the other returned home. And the warriors went on up the river
to a town on the other side of Kalama. The people came down to the water and began to fight, and
many were killed. But presently, one of the young men heard one of the warriors say; 'Quick let us
go home. That Indian has been hit.'
Now he thought; 'Oh, they are ghosts.' He did not feel sick, but he had been shot. So the canoes
went back to Egulac, and the young man went back to his house and made a fire. And he told
everybody and said; 'Behold, I accompanied the ghosts, and we went to fight. Many of our fellows
were killed and many of those that attacked us were killed. They said I was hit, but I did not feel
sick.'
He told it all, and then he became quiet. When the sun rose, he fell down. Something black came out
of his mouth. His face became contorted. The people jumped up and cried. He was dead.
War of the Ghosts (1932)
Bartlett found that their accounts were
distorted in several ways that,
generally, made them more consistent
with a Western world – view.
Specifically he found the following;
Findings/Results
Some things in the story were changed by the
participants, especially parts of the story that were
difficult for the participant to comprehend (i.e.
ghosts and the Indian's death). Ghosts coming out
of the mouth of the unconscious Indian was
commonly written. The excuse for not fighting "I
have run out of arrows" was avoided and instead
put down to "worried relatives", because it was
more familiar to the participant.
Every participant rationalized the.story to some
degree
Findings/Results
Some added material to the story to bring it into
closer agreement with their prior knowledge and
beliefs (for example he had a fever before he died).
There was a tendency for males to forget the 'no
arrows' excuse for joining the war. This was because
many men were going off to war and relatives would
miss him were in the forefront of the participants
minds.
Findings/Results
Bartlett found that participants tended to alter their
memories in order to make the story more coherent.
This often involved them down playing the things
they did not understand, such as the supernatural
elements: The participants were not reading back a
copy of the story but reconstructing it from the main
details held in their memory.
Evaluation of Bartlett’s
study
The ecological validity of the War of the
Ghosts lab study has been questioned.
Whilst Bartlett rejected the artificiality
of traditional stimulus such as nonsense
syllables ( Ebbinghaus) and word lists to
test memory, his use of a native
American folk tale was " about as similar
to normal prose as nonsense syllables are
to words
Evaluation of Bartlett’s
study
Wynn & Logie (1998) did a similar study with students
using " real - life" events experienced during their
first week at university at various intervals of time
ranging from 2 weeks to six months.
They found that the initial accuracy of recall was
sustained throughout the time period, suggesting
that schema-induced memory distortions may be less
common in naturalistic conditions than in the
laboratory.
Evaluation of Bartlett’s
study
Furthermore Bartlett’s study wasn't a very well
controlled study. Bartlett did not give very specific
instructions to his participants ( Barlett, 1932 " I thought
it best, for the purposes of these experiments, to try to
influence the subject's procedure as little as possible".)
As a result, some distortions observed by Bartlett may
have been due to conscious guessing rather than
schema-influenced memory
Gauld and Stephen ( 1967) found that the instructions
stressing the need for accurate recall eliminated almost
half the errors usually obtained.
Further support for the influence of schemas on
memory at encoding point was reported by
Anderson and Pichert ( 1978).
2nd supporting study
schema theory
( Anderson & Pichert, 1978)
Subjects asked to adopt a particular perspective:
Home-buyer
Burglar
Then read a passage about two boys playing truant from
school...
Schemata and Memory
(Anderson & Pichert, 1978)
[Coding: Burglar items (18); Homebuyer items (18)]
There are three color TV sets in the house. One is in the large
master bedroom (which has a three piece bathroom en suite), one is
in the main floor family room, and one is in Tom's bedroom. The
house contains four bedrooms in all, plus an office, family room,
and three washrooms. In addition to the TV, the family room
contains a new stereo outfit , a microcomputer, a VCR, and a rare
coin collection.
The boys enter the master bedroom. Beside the jewelry case
in the closet they find Tom's father's collection of pornographic
video tapes. They select their favorite (an encounter between a guy
and 12 women in a park in downtown Kitchener) and go to the
family room to watch it.
Evaluation of schema theory
Anderson & Pichert ( 1978)
In a classic experiment, Pichert and Anderson1 asked
participants to read a story in which a house was
described.
The participants were told to read the story from one
of two perspectives, either a potential home buyer or
a burglar.
After a delay, participants were asked to recall as much
as they could about the story.
Proportion Recalled
During this first recall session, participants recalled significantly more
information about the house that was relevant to their perspective
•(e.g., the potential home buyer might remember defects in the house,
• burglars might remember information about the entrances and exits)
•than information that was relevant to the other perspective,
Identity
Items
After the first recall session, participants were told to
think about the story again, but this time, from the other
perspective (potential home buyers were now told to be
burglars, and vice versa).
Then, without reading the story again, they were told to
recall as much as they could about the story again.
Change in
proportion recalled
During this second recall, participants were able to recall
information about the house that was relevant to their
new perspective, but which they had not recalled before.
First identity/second identity
Items
This result shows two things:
1.) The information that was irrelevant to their original
perspective (schema) was actually learnt ( encoded ) and
2.) This information was not accessible unless a relevant
perspective (schema) was activated.
Evaluation of Anderson &
Pichert (1978)
This experiment was also conducted in a
lab, so ecological validity may also be an
issue here.
However the strength of the experiment
was its variable control, which allowed
researchers to establish a cause-and-effect
relationship how schemas affect memory
processes.
Evaluation of Schema theory
Strengths:
Support for the influence of schemas on cognitive
processes is widespread. Bartlett (1932) described
how schemata influence memory in his classic
study based on a Native American folktale.
Helps explain many cognitive processes
(perception, memory, reasoning)
Helps explain the reconstructive nature of memory
– eg eye-witness testimony, stereotyping, gender
identity, cultural differences
General comment on schema
theory
Finally, one of the main problems of the
schema theory is that it is often very difficult
to define what a schema is.
Cohen (1993) points out that "the whole idea
of a schema is too vague to be useful' and
argues that schema theory provides no
explanation of how schemas work.
Schemas are untestable
Schema processing is not fully understood
General comment on
schema theory
Nevertheless, there is enough research to
suggest schemas do affect memory processes
knowledge, both in a positive and negative
sense.
They do simplify reality, and help us to make
sense of current experiences. Schemas are
useful concepts in helping us understand how
we organize our knowledge.