Slide 2 Thinking part I Mental Representations and Visual
Imagery Mind Reading Slide 3 Overview Nature of mental
representations analogical vs. symbolic representations
Relationship between imagery and perception Distortions in mental
maps Mind reading predicting what somebody is thinking of based on
brain activity Slide 4 Study of Imagery Banned by behaviorists
Possible subject of study in cognitive psychology Cognitive
psychology is distinguished from the earlier behaviorism by its
claim that there are internal representations of knowledge on which
the mind operates However, this is a difficult area of study Mental
images are subjective How can we show that images are used? How are
they represented? Stephen Kosslyn (did much of the research on
mental imagery) Slide 5 Nature of Mental Representations The analog
vs. propositional debate analog representations: the representation
has the same structure as the thing represented symbolic /
propositional representations: a sentence- like description of the
image, non-spatial Slide 6 Analog Images vs. Propositions Analog
Imagine: The can is on the box. The can is black Propositions
(Symbolic representation) on( can, box ) black( can ) Slide 7
Imagery and Analog Representations Most studies on imagery argue
for analog representations (e.g., mental rotation, brain imaging
studies). Yet mental images are not processed exactly the same as
visual images Slide 8 Imagery = perception in reverse? Slide 9
Imagery & Perception If the mechanisms used to perceive stimuli
are also used to generate mental images, then we should predict:
Mental images should be quasy pictorial Mental images should
activate some of the brain areas involved with visual processing
Slide 10 Just as in visual images, level of detail in mental images
can vary Does a rabbit have eyebrows? Imagine a bee next to a
rabbitImagine a elephant standing next to a rabbit Does a rabbit
have eyebrows? Slide 11 Visual Imagery and Hemispatial Neglect
(Bisiach and Luzzatti, 1978) Mental images from opposite sides of
an imagined public landmark Slide 12 Evidence from brain imaging
(fMRI) for involvement of visual processing areas during visual
imagery (Le Bihan et al., 1993) Slide 13 Differences between
pictures and mental images Mental images are more difficult to be
reinterpreted Mental image = percept + interpretation Slide 14
Imagery and Ambiguous Figures What would this object look like when
rotated 90 degrees? Slide 15 Slide 16 Imagery and Ambiguous Figures
If you see one interpretation, it is very difficult to then imagine
the other interpretation (unless you are trained in this task) One
difference between imagery and visual perception: visual images,
unlike mental images, can be easily reinterpreted Slide 17 Mental
Images might miss important aspects of object being imagined
Imagine you have a cube between your thumb and index finger. One
corner of the cube touches your thumb, and the diagonally opposite
corner touches your index finger. Now, point to the locations of
the rest of the corners in space. Many people point (incorrectly)
to four points on the same plane half way between the top and
bottom corners. Correct Solution: Slide 18 Imagine this object Does
this figure contain a parallelogram? a)no b)yes c)not sure d)what
is a parallelogram?? parallelogram Slide 19 Mental Rotation Can
mental images be transformed in a way analagous to physical
objects? How could we tell? Mental rotation task: look at the time
it takes to rotate two shapes into correspondence Demo experiment:
http://bjornson.inhb.de/?p=55 http://bjornson.inhb.de/?p=55 Slide
20 Example Trials same different same different samedifferent Slide
21 Results linear relationship between angle of rotation and
reaction time in object comparison The mental process seems to be
analogous to the physical process of rotation. Slide 22 Mental
distortions in Cognitive Maps Slide 23 Which is further west?
a)atlantic entrance to the panama canal b)pacific entrance to the
panama canal Slide 24 Which is further east? a)Florida b)Chile
Slide 25 Which is further south: a)Philadelphia b)Rome Slide 26
Which is further east? a) Reno b) San Diego Slide 27 Cognitive maps
are affected by conceptual knowledge Relative locations of small
regions is determined by a conceptualization of larger regions.
Line of reasoning: Nevada is east of California Reno is in Nevada,
San Diego in California, Therefore, Reno must be east of San Diego
Slide 28 Experimental evidence for hierarchical organization in
cognitive maps Ss. study maps. Later, from memory, they judge
relative position of locations x and y Performance was better when
superordinate information was congruent with question Congruent
Incongruent (Stevens and Coupe, 1978) Slide 29 Summary Imagined
information is processed in similar ways to perceptual information
Neuroscience evidence (fMRI) Neuropsychological evidence Behavioral
evidence: Kosslyn studies/ Scanning studies Mental rotation But
there are also differences: Mental images are difficult to
reinterpret Cognitive distortions in mental maps Slide 30 Mind
reading Slide 31 Mind Reading (or Thought Identification) Viewing a
BottleViewing a Shoe If the brain response is different for
different kinds of stimuli, can we predict what somebody is
thinking of solely based on the brains response? brain response
Slide 32 Faces Cats Scissors Chairs Houses Bottles Shoes Scrambled
Pictures slides courtesy of Jim Haxby Haxby et al. (2001) can
predict with 96% accuracy stimuli from 8 categories Slide 33
Reconstructing the Mental Image If we can predict what somebody is
looking at, can we also reconstruct what somebody might be looking
at from just the brains response? Image Brains response
Mathematical Model Reconstructed image Is this science fiction?
Slide 34 Reconstruction from brain activity
http://www.youtube.com/watch?v=nsjDnYxJ0bo&feature=related
Nishimoto et al. (2011), "Reconstructing Visual Experiences from
Brain Activity Evoked by Natural Movies", Current Biology.Current
Biology Slide 35 Reconstruction from Brain Activity
http://www.youtube.com/watch?v=KMA23JJ1M1o Volunteers watched clips
of several movies while in a fMRI scanner. An algorithm later found
movie clips that best explained the brain activity Nishimoto et al.
(2011) Slide 36 Reconstructing Speech from Human Auditory Cortex
http://www.bbc.co.uk/news/science-environment-16811042
Reconstructed
