Transcript Cognitive Psychology - University College Dublin

Cognitive Psychology
Lecture 4: Mental Imagery
1st October 2008
James Matthews
Mental Imagery
Today’s Lecture:
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What is mental imagery?
Types of imagery
Nature and characteristics of imagery
Uses of mental imagery
Research into mental imagery
Imagery debate
What is mental imagery?
In Literature:
Descriptive or figurative language
that excites the senses
"masses of flowers
load the cherry branches
and color some bushes
yellow and some red..."
(William Carlos Williams)
Mental Imagery
In psychology:
Sensation without perception
- When we read poetry it can happen
- When we ‘picture’ something
- When we ‘sing’ in our heads
Mental Imagery
There are mental images associated with each of
the senses:
– Pictures (From memory, novel items)
– Sounds (Speech, music, noises)
– Smells (Perfume, odours)
– Taste (Curry, coffee) - Smell????
– Touch (Fur, sandpaper, silk)
– Actions (Running, Stretching)
Mental Imagery
There are two main approaches to defining mental
imagery (Wraga & Kosslyn, 2002) :
• Intuitive: The experience of ‘seeing’ with the
minds eye
• Theoretical: A cognitive representation that gives
rise to the experience of perception in
the absence of the appropriate
sensory input
Mental Imagery
How many windows are on the front of your
house?
Intuitively this feels like a picture in the head
Theoretically, if the person gets this right then there must
be some sort of stored representation of the house.
(Otherwise they would have to have already counted the
windows and stored this info as a semantic fact.)
Nature of Images
Our ability to form mental images is:
• Spontaneous - Don’t think of an elephant
• Effortless - E.g. It occurs during sleep
• Extremely Useful - Problem solving &
mental practice
Characteristics of Images
• Vividness
– The level of clarity, realism or richness of a mental
image
• Controllability
– The degree to which one can manipulate or control a
mental image
• Associated Emotions
– Images may invoke feelings, physiological reactions.
Vividness
Controllability
Associated Feelings
Uses of Mental Imagery
Kosslyn et al. (1990) carried out a diary study where
people recorded their imagery usage.
» Daydreaming (with remarkable results!)
» Memory aid (shopping list, method of loci)
» Emotional/Motivational (‘visualise goals’)
» Giving/Receiving directions
» Mental practice (serious business!)
Daydreaming
– Hypnagogic dreaming often occurs during the semiconscious descent into sleep.
– It is an image-rich experience
– There have been some famous outcomes from
hypnagogic dreaming. . .
Daydreaming
Rene Descartes
Founder of modern
mathematics
(Cartesian geometry)
Daydreaming
Daydreaming
Friedrich August Kekulé von
Stradonitz
German organic chemist
Friedrich August Kekulé von Stradonitz
– Discovered the
structure of Benzene
Friedrich August Kekulé von Stradonitz
– By daydreaming of a
serpent biting it’s
own tail
Friedrich August Kekulé von Stradonitz
Mental Practice
• Important in ‘performance’ settings
(Sports, stage, surgery. . .)
• Mental practice refers to a particular application
of mental imagery in which performers practice
in their heads or rehearse their skills symbolically
before actually executing them.
Mental Practice
“On the days we’re doing gigs I’d visualize the
venue all through the day; see myself sitting on
the stage. That’s the whole focus of the day, the
gig. It’s important to focus”
Martin Hayes – Musician
“I work on imagery training.
Sometimes when I am sitting
in traffic, I will do a couple of
crosses in my head.”
David James - Portsmouth
Some studies on Mental Practice
• Smith & Holmes (2004)
• 40 male golfers engaged in a putting task
twice a week for 6 weeks
• One group watched videos of themselves
putting
• Another group read golf books
Some studies on Mental Practice
• Smith & Holmes (2004):
• There was no difference in putting
performance in pre-test
• In post-test those who watched a video of
themselves putting were significantly better
Some studies on Mental Practice
• Smith & Holmes (2004)
• This would suggest there are benefits to
seeing yourself engaged in performance
• Indicates benefits of imagery
Some studies on Mental Practice
• Jackson et al. (2004)
• Worked with a patient who had suffered
from a stroke
• Patient engaged in mental practice for
certain difficult foot movement patterns
Some studies on Mental Practice
• Jackson et al. (2004)
“The findings show that mental practice, when
combined with physical practice, can improve the
performance of a sequential motor skill in people who
had a stroke, and suggest that mental practice could
play a role in the retention of newly acquired abilities”
Some studies on Mental Practice
• Jarrod Cunningham, former London Irish rugby
player – Amyotropic Lateral Sclerosis
“I try to visual sluggish electrons in the brain and spinal
cord and to use mental imagery to inject energy and
power into them”
• Ievela & Orlick (1991) - Studied 32 injured athletes
• Certain kinds of mental imagery, (along with goal
setting & self talk) were techniques most strongly
associated with fast healing.
Some studies on Mental Practice
• Simonton et al (1978)
• Positive findings as a result of implementing
relaxation and imagery on medically incurable cancer
• 22.2% demonstrated total remission
• Hall (1983) supports this
• Hypnosis and Imagery on lymphocyte function
• Results showed increased immune response
• How do this process work???
Mental Practice – Key Points
• Mental practice (MP) is less effective than physical
practice (PP)
• MP when combined with PP seems to provide a
greater skill learning experience than either on their
own.
• MP improves cognitive skills better than motor skill
tasks.
• Experts benefit more from MP than do novices
regardless of the type of skill being practiced.
• Imagery ability mediates the relationship between MP
and motor skill performance.
• Effects of MP begin to wear off after 2 weeks unless
refreshed.
Imagery Research
Behaviourism:
• An approach to psychology that dominated the
discipline for the early part of the 20th century
• Was solely concerned with observable
behaviours
• As a result imagery was not studied. Its existence
was even questioned
Imagery Research
• Early attempts to measure imagery ability took
the form of subjective self-report designs (Galton,
1890. Betts, 1904)
• “Imagine your breakfast table. Picture the cutlery.”
Rate the vividness of the image on the following
scale. . .
Betts Questionnaire
Key for answering questions:
With respect to the mental sound suggested in each of the questions of the test,
is the image which comes before your mind,
1 Perfectly clear and as vivid as actual experience, or
2 Very clear and comparable in vividness to the actual experience, or
3 Moderately clear and vivid, or
4 Not clear or vivid but recognisable, or
5 Vague and dim, or
6 So vague and dim as to be hardly discernible, or
7 No image present at all, you only knowing that you are thinking of the object
Problems with Self Report Measures
• Answers are too vague to elicit uniform understanding
• Rating more likely to be influenced by how good an
imager the participant thinks they are rather than how
vivid the image is
• Does not take into account familiarity with the stimuli (Was
breakfast rushed/relaxed/skipped)
• Cannot verify that the correct image is being considered
• But, mental chronometry might alleviate some concerns…
Objective tests of imagery
Shepard & Metzler (1972) developed the mental rotation test
Objective tests of imagery
Shepard & Metzler (1972) developed the mental rotation test
Objective tests of imagery
Shepard & Metzler (1972) developed the mental rotation test
• Performance can be timed
• Answers are either right or wrong
• Test requires controllability as well as vividness
The Imagery Debate
• This refers to two differing viewpoints as to the exact
nature of (visual) images
• The Analog Viewpoint: Visual mental images are
analogous to pictures in the head.
Championed by Stephen Kosslyn
• The Propositional Viewpoint: Although we experience
images as pictures, they are stored as non-pictorial
abstract concepts.
Championed by Zenon Pylyshyn
In a nutshell
Functional Equivalence
Kosslyn, S.
Image is a picture
Propositional Info
Pylyshyn, Z.
Image is a description
– 3 sided shape
– 3 angles of 60˚
– Small lines bisecting
Functional Equivalence
Evidence
• Anecdotal evidence: The experience of imaging feels very
much like seeing a picture in ones mind
• Experimental evidence: Shepard & Metzler (1972) found
that the further the angle of rotation, the longer it took for
people to decide if two shapes were similar
Functional Equivalence
Evidence
Functional Equivalence
Evidence
Experimental evidence: Kosslyn, Ball & Reiser (1978)
asked participants to memorise this map:
Functional Equivalence
Evidence
• Experimental evidence: Kosslyn, Ball & Reiser
(1978)
• Participants were instructed to focus on one
landmark
• This done they were asked to focus on a different
one
• The time taken to focus on the second one was
positively correlated with the distance between
the two.
Functional Equivalence
Evidence
Functional Equivalence
Evidence
• Experimental evidence: Kosslyn, Ball & Reiser (1978)
• But. . .
It is possible that the way the questioning was worded
caused participants to inadvertently treat the image as a
picture and behave appropriately.
• Experimenter Expectancy Jolicoeur and Kosslyn (1985)
Functional Equivalence
Evidence
• Neuroimaging evidence: Kosslyn & Sussman (1995)
• PET scans showed that the same parts of the brain are
used in imagery as in direct perception
• These findings are supported by appropriate brain injury
findings (Farah, 1988)
Propositional Theory
Evidence
• Experimental evidence: Chambers and Reisberg (1985)
• Images cannot be re-interpreted.
Propositional Theory
Evidence
• Experimental evidence: Chambers and Reisberg (1985)
• Images cannot be re-interpreted.
Propositional Theory
Evidence
• Experimental evidence: Reed (1974)
• You cannot notice new things in an image
• Theoretical evidence: Pylyshyn argues that images can be
non-commital in various ways
Propositional Theory
Propositional Theory
The Imagery Debate
• The essential argument is based around the type of code
that an image is written in the brain with.
• However Kosslyn has recently allowed for some
propositional coding in his theory
– Surface representation – Produced in visual cortex
– Deep representation – Information stored in LTM to produce
surface representation. Both analog and propositional information.
• Pylyshyn has acknowledged that there are pictorial
representations at some stage in the imagery process
– Epiphenomenal
Mental Imagery
Today’s Lecture:
•
•
•
•
•
•
What is mental imagery?
Types of imagery
Nature and characteristics of imagery
Uses of mental imagery
Research into mental imagery
Imagery debate
Reading
Some imagery chapters:
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Eysenck and Keane, Ch 3 / VISUAL IMAGERY
Matlin, Cognition, Ch 6
Sternberg, Ch 7
Reisberg, Ch11
Articles:
Pylyshyn, Z. (2003) Return of the mental image: are there really
pictures in the brain?. Trends Cogn. Sci. (7) pp. 113–118
Kosslyn, S. M. L., Ganis, G. & Thompson, W. L. (2003). Mental
imagery: Against the nihilistic hypothesis. Trends-in-Cognitive Sciences, 7, 109-111.