Transcript Mental Imagery

Mental Imagery
Chapter 10
Historical Overview

3 basic ages of mental imagery:
– the prescientific period known as the
philosophic period
– the measurement period
– the cognitive and neurocognitive period
Current debate...
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Is visual imagery really visual or is it
governed by general-purpose cognitive
processes?
– When I “image” a tree, the same (or very
similar) neurons/processes are activated
as when I originally saw the tree
– Representations used in imagery are not
the same as those used in real
perceptions.
3 Theories...
1. Pavio’s Dual-Coding Hypothesis
2. Conceptual-Propositional Hypothesis
3. Functional-Equivalency hypothesis
Paivio's Dual-Coding Theory
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The basic tenant of this theory is that
information is mentally represented
either in a verbal system or a nonverbal
(analogical) system (or both).
– Each system contains different kinds of
information.
– Each concept is connected to other related
concepts in the same system and the other
system.
– Activating any one concept also leads to activation
of closely related concepts.
Basic Result: Paivio (1971)
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Give S's a long list of pictures or words
to remember.
Later, test memory with either a recall or
recognition memory test.
– S's recall more pictures than words.
Basic Result: Paivio (1971)
Explanations:
1) The Imagen system has superior
memory abilities to the Logogen
system.
2) Representing ideas in both systems is
superior to representing ideas in only
one system.
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Basic Result: Paivio (1971)
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which of the explanations is correct?
– Compare:
• Memory for Verbalizable and Nonverbalizable
pictures.
• High-Imagability words (e.g., DESK) and LowImagability words (e.g., EFFORT).
• S's instructed to form mental images of words
and S's not instructed to form images of words.
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Results: Across all these situations, the
evidence consistently supports claim that
having two representations = superior memory.
Can using dual coding ever
interfere with/disrupt memory?
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Schooler & Engstrom-Schooler (1990)
– S's are shown a videotaped robbery. (This
creates a visual memory.)
– S's then either:
1) Are asked to imagine the robber.
2) Are asked to describe the robber.
3) Are asked to do a series of math problems.
– S's complete a recognition memory test
picking the robber out of a lineup of eight
persons.
Results:Creating two codes can disrupt memory for
information that is only represented in one code.
Another example: Wilson & Schooler (1991)
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S's tasted different kinds of strawberry
jam and either:
– thought about it's taste
– described it's taste.
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S's then rated the quality of each jam.
conceptual-propositional
hypothesis (Anderson and Bower)
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Taking conservation approach, claimed
wasn’t scientifically viable to suggest
that memories are carried in memory
like photos
conceptual-propositional
hypothesis (Anderson and Bower)
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we store interpretations of events,
whether they be verbal or visual, rather
than the imaginal components.
– Anderson and Bower explain that concrete
concepts are coded by a rich set of
predicates that bind concepts together.
..."the only difference between the internal
representation for a linguistic input and a
memory image is detail of information"
conceptual-propositional
hypothesis (Anderson and Bower)
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Anderson and Bower’s conceptualpropositional hypothesis is a good
model theoretically
– The hypothesis does have trouble
accounting for some imaginal processes
Functional-equivalency
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The functional-equivalency hypothesis
was first proposed by Shepard and
Kosslyn and states that imagery and
perception are extremely similar.
– Shepard and Kosslyn introduced mental
rotation of visual stimuli in memory.
• Relationship between time required for a
specific mental rotation and the actual degrees
of rotation
Functional-equivalency
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Conclusion…
Visual images reflect internal
representations that operate in a way
that is analogous to the functioning of
the perception of physical objects.
Neurocogntitive Evidence
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Many studies haven been done to
obtain neurocognitive evidence for
supporting the concept of mental
imagery.
– People who have damage to the left
hemisphere have trouble with verbal
memory while patients with damage to the
right hemisphere have trouble with visual
material.
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findings support dual-coding hypothesis
Neurocogntitive Evidence
– Different areas of brain are associated with
different cognitive tasks
– visual imaginal tasks and vision seem to be
situated in similar locations in the brain
– visual imaginal tasks, which require
associative knowledge, activate brain
regions affiliated with memory and vision
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Support functional-equivalency
cognitive map
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a map that allows us to navigate
through the world.
– Thorndyke and Hays-Roth (1982) found
two types of knowledge that are used in
moving about from day to day:Route
Knowledge and Survey Knowledge.
cognitive map
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Route knowledge is the knowledge that
we draw on for getting around.
– If I gave someone directions to my house, I
am using Route Knowledge.
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Survey Knowledge is knowledge that
allows us to know understand the
general spatial relationships that are
involved.
– I could tell the person that my house was
south of the University.
cognitive map
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Mental maps tend to be biased by the
person drawing them.
– In a map drawn by a student in Australia,
the Australian continent was at the top of
the map instead of the bottom.
Synesthesia: The Sound of
Colors
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Synesthesia is a condition where
sensations usually experienced in a
single modality are experienced in two
modalities.
– This conditiongive psychologists some very
interesting data and research.
– Some examples of synesthesia are
receiving an auditory signal or sensation in
a visual modality, where it obviously
shouldn’t be.
Synesthesia: The Sound of
Colors
Seeing the words to OVER THE RAINBOW, a form of synesthesia.