Human Cognitive
Processes: psyc 345
Ch. 10 Visual imagery
Takashi Yamauchi
© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)
• (Q1) How are images represented in the
brain?
• (Q2) How are perception and imagery
linked?
• (Q3) Are the male brain and the female
brain different? If so, how?
• (Q4) Why are there many more autistic
boys than girls?
• (Q1) How are images represented in the
brain?
• (Q2) How are perception and imagery
linked?
• Imagery
• DVD: Secrets of the mind
– Ch. 10 10 min
• How many windows do you have in your
house/apartment?
• How is the furniture arranged in your
bedroom?
• Are an elephant’s ears rounded or
pointed?
How did you find that?
• Did you navigate your rooms one by one?
• Represent images of your rooms and
house, and visit each one, as in a
computer game?
• visual imagery.
– Experiencing a sensory impression in the
absence of sensory input.
• What is imagery for?
– In a memory test, visualizing images of
words help remember more accurately.
– Many top athletes use visual imagery to
enhance their athletic performance.
– People use imagery to solve problems.
• Einstein developed the theory of
relativity by imagining himself
traveling beside a beam of light.
• Good mathematicians are good at
visualizing math problems.
Imagery and Perception
• Perception
– You get physical input. And your neurons are
responding to it.
• Imagery
– You don’t have physical input, but your
neurons are responding to it.
Imagery and Perception
• Do they share the same mechanism?
• How are they related?
Imagery and Perception
• Can you form imagery of
– Red apple, green apple, yellow apple,
– Blue apple, orange apple, purple apple
• Can you form imagery of a zebra?
– Can you seen stripes in your zebra?
– Can you count how many stripes the zebra
has?
Imagery debate
• How do we create mental images?
• Analogue
– Mental images and perceptual images both
involve spatial analogs of the stimulus.
• Propositional
– Mental images are created by the same
mechanism that creates language
(propositional mechanism)
– The spatial experience of mental images are
an “epiphenomenon”.
Analog Hypothesis
• Mental images are internal representations
that operate in a way that is analogous to
the functioning of the perception of
physical objects.
– Functional-equivalency hypothesis
• Coglab
• Mental rotation
Representation
• Analog vs. digital representation
Analog representation
Fig. 2.11, p.53
Example:
• Want to compare whether or not the two
figures are the same.
• How do you make a judgment?
• For physical objects, you will simply rotate
them, and compare them.
Same?
What is the consequence of
rotation?
• The time required for comparison
corresponds to the angle of rotation.
Y axis: Comparison
time
X axis: The Angular distance
between two figures
Mental rotation experiments
• Show two objects side by side
• Subjects were asked to determine whether
the two objects were the same.
Do people rotate objects
mentally?
What do you measure? What
kind of results do you expect?
• Subjects’ response times for their yes-no
judgments.
• Their response times should be linearly
related to the angular departure of the two
objects.
Experiment:
• Subjects were presented with two objects
(either together or in sequence).
• Subjects judged whether or not the two
objects were identical.
• Dependent measure:
– Response time and accuracy
Results
What can you say
from these results?
The response times
observed in this task
were proportional to
the angular
departure of two
shapes.
• What do this tell you?
• Does this relate to the functionalequivalency hypothesis?
• How?
Mental scanning •
(Kosslyn et al.
•
1978)
Ss were shown a map of an
imaginary island.
The map showed various objects
(e.g hut, tree, hill,..)
• Ss studied the map until they
could reproduce it from memory.
• After that, Ss were asked to
picture the map and mentally
scan the picture from one location
(tree) to another (hill).
• When mental scanning was
completed, Ss pressed a key
Mental scanning
(Kosslyn et al.
1978)
• Ss scanning times
were linearly related
to the physical
distances between
locations
Mental
scanning time
Physical distance between locations
Finke & Pinker (1982)
• Ss first saw (a),
and then (b).
• The task was to
judge if the arrow
pointed to any of
the dot.
• Ss took longer to
respond for
greater distances
between the arrow
and the dot.
Ss were asked to imagine
animals, such as an elephant
and a rabbit next to each other.
The experimenter asked “Does
a rabbit have whiskers?”
RT = 2.030 ms
Ss were asked to imagine
animals, such as a fly and a
rabbit next to each other.
The experimenter asked “Does
a rabbit have whiskers?”
RT = 1.870 ms
Implications
• Ss answered the question about the rabbit
more rapidly when it filled more of the
visual field.
• Mental images are spatial just like
perception
Imagery and the Brain
• Compare the brain area that are activated
– (1) when a person observed perceptions of
actual visual stimuli (perception)
– (2) when the person was imagining the
stimulus (imagery)
• Ganis et al. (2004)
First, Ss studied stimuli in a
booklet (line drawings of 90
objects)
Experiment: Imagery and
perception conditions were
alternated.
Perception condition:
The name of a picture is
presented auditorily.
Ss saw a low contrast line
drawing, and answered the
same question as asked in the
imagery condition (such as “Is
the object higher than it is
wide?” )
• Ganis et al. (2004)
First, Ss studied stimuli in a
booklet (line drawings of 90
objects)
Experiment: Imagery and
perception conditions were
alternated.
Imagery condition:
Ss closed their eyes.
The name of a picture is
presented auditorily.
Ss generated the corresponding
visual mental image and
answered a question such as “Is
the object higher than it is
wide?”
Perception
Imagery
Perception - Imagery
Frontal areas
The activation
patterns appear
identical
Perception
Imagery
Perception - Imagery
Parietal and
temporal
areas
The
activation
patterns
appear
identical
Perception
Imagery
Perception - Imagery
Occipital
areas
The activation
patterns
appear
somewhat
different
Transcranial Magnetic Stimulation
• Apply a magnetic field to a skull and
disrupt the activity of neurons in a
particular region.
• Demo: (4:15)
– http://www.youtube.com/watch?v=XJtNPqCjiA
The perception task:
Ss were asked to indicate whether the stripes in two of the quadrants
(e.g., the stripes in 3 longer than stripes in 2?)
The imagery task:
= the perception task, but Ss were asked to close their eyes and make
judgments based on their mental image of the display.
Manipulations:
TMS was directed to the visual area while Ss were making judgments.
TMS was directed to another part of the brain while Ss were making
judgments
Results
TMS slowed Ss’ responses both in the imagery and perception conditions.
Implications
• The perception and imagery tasks are
carried out by the same brain areas.
Neuropsychological case studies
• Farah 2000
– Patient M. G. S
– An educated young woman
– Her right occipital lobe removed as treatment
for a sever case of epilepsy.
– The mental walk task was given before and
after the operation
• The mental walk task
– She visually imagined walking toward an
animal
– And estimated how close she was when the
image began to overflow.
• “overflow” means that the mental image was too
big so that she could not see the entire animal at
once in her mental image.
Mental walk test: before and
after the operation.
Before the
operation
After the
operation
Before the operation, she
could mentally walk to the
image of a horse within 15
feet before “overflowing”.
After the operation, she
could mentally walk to the
image of a horse within 35
feet before “overflowing”.
Explanation:
Removing part of the visual
cortex reduced the size of
her field of view.
 The visual cortex is
important for imagery
Other case studies
• Perceptual problems are accompanied by
problems with imagery.
– People who have lost the ability to see color
due to brain damage are also unable to create
colors through imagery.
– People who have unilateral neglect in
perception also have unilateral neglect in
imagery.
Unilateral neglect
• Often caused by damage to the parietal
lobe.
• People with unilateral neglect pay attention
to only one side of the visual field and
ignore the other side of the visual field.
– http://www.youtube.com/watch?v=ADchGO0kGo
Imagery and unilateral neglect
• Bisiach & Luzzatti (1978) tested the
imagery of a patient with unilateral neglect.
• The patient imagined himself standing at
one of a familiar Piazza and named the
objects around the Piazza.
When the patient
imagined himself
standing at A, he
could name objects
indicated by a’s.
When he imagined
himself at B, he
could name objects
indicated by b’s.
Fig. 9-18, p. 343
Implications
• There is a strong correspondence
between the physiology of mental imagery
and the physiology of perception.
Dissociations Between
Imagery and Perception
• Evidence for double dissociation?
Dissociations Between
Imagery and Perception
• R.M.
• Damage to occipital and parietal lobes
• Could draw accurate pictures of objects in
front of him
• Could not draw accurate pictures of objects
from memory (using imagery)
Dissociations Between
Imagery and Perception
• C.K.
• Inability to name pictures of objects, even
his own drawings, in front of him
• He could draw objects in great detail from
memory (using imagery)
CK labeled (a) as a
“feather duster” (the
dart), “a fencer
mask” (the tennis
racket), and a “rose
twig with thorns (the
asparagus).
CK was able to draw
objects from
memory in rich detail
Fig. 9-19, p. 344
Neuropsychological Results
• Evidence for a double dissociation
between imagery and perception
• Indicates separate mechanisms
• Also evidence for shared mechanisms
The mechanisms of perception and imagery overlap only
partially.
Perception: mostly lower visual receiving areas and
some higher visual areas
Imagery: mostly higher visual areas, and some lower
visual receiving areas.
(Q3) Are the male brain and the female brain
different? If so, how?
(Q4) Why are there much more autistic boys than
girls?
male brain vs. female brain
– Verbal abilities: female > male
– Spatial abilities: male > female
Male vs. female
• http://www.youtube.com/watch?v=NoCPDvQBG5Y&feature
=related
male vs. female (30 sec)
• http://www.youtube.com/watch?v=of0SxqoYNw&feature=related
Autism
1:00
– http://www.youtube.com/watch?v=r1KQCJzKaN0&feature=related
3:02
– http://www.youtube.com/watch?v=srVKHiEPVss&feature=related
– http://www.youtube.com/watch?v=filK9gZw4rA
• Female brain: empathizing
brain
• Male brain: systemizing brain
• Baron-Cohen (2002), Trends
in Cognitive Sciences
• The extreme male brain theory
of autism (by Baron-Cohen)
• Autism is an extreme
expression of the male brain.
• The female brain: empathizing
• F>M
– Sharing and turn-taking (F>M)
– Responding empathically to the distress of other
people (F>M)
– Values in relationships (F>M)
– Talk about emotion (F>M)
– babies look longer at faces (F>M)
• M>F
–
–
–
–
Psychopathic personality disorder (M>F)
Competition and rough tumble play (M>F)
Aggression (M>F)
Murder (M>F) (male-male homicide was 30-40 times
more frequent than female-female homicide)
• The male brain: systematizing
• M>F
– Toy preference – vehicles (M>F)
– 3D construction (Lego) (M>F)
– Mental rotation (M>F)
– Map reading (M>F)
– Motoric judgments (e.g., judge which objects
are moving faster) (M>F)
– engineering, math, and physics majors (M>F)
The extreme male brain theory of
autism (by Baron-Cohen)
• 1 in 200 children have one of the autistic
spectrum conditions.
• The sex ratio is at least 10 males to every
female.
• Overrepresented in children whose
parents / grand parents are engineers
– (Baron-Cohen et al.; Autism, 1997, 1, 153163)
• Autistic children: Impaired “female brain” /
impaired empathizing
• Mindreading (predicting another’s feelings)
– F>M>A
• Reading the mind in the eyes (discrimination
emotions from expressions in the eyes) F>M>A
• Eye contact: F>M>A
• Language development (vocabulary) F>M>A
• Preference for rule-based, structured, factual
information; A>M>F
• Preference for constructional toys: A>M>F
• Collecting: A>M>F
• Obsession with closed/well-defined systems
(e.g., computers): A>M>F
Using imagery to improve memory
• Using imagery as mnemonics
• How does it help? (4:20)
– http://www.youtube.com/watch?v=L1mweFSq
ACU&feature=related