Mental Imagery
The evidence in favor of us seeing
actual pictures in our mind.
Mental Rotation
• Shepard & Metzler (1967) did the classic
mental rotation experiment.
– Show people two arbitrary, 3-D objects at
different orientations.
– Ask people to judge whether the objects are
mirror images of each other or not.
– The amount of time it takes people to answer is
directly proportional to the degrees of rotation
by which the objects differ.
Relative size & Image scaling
• When asked to imagine two objects, it takes
longer to make judgments about the smaller
object
• It also takes longer to make judgments
about smaller features of objects
Image scanning
• Give people a picture of something, such as
a map of a simplistic island and have them
memorize it.
• Ask people to scan the image from one
point on the map to another.
• The time it takes to do this is proportional to
how far apart the two points are.
The Mind’s Eye hypothesis
• Kosslyn proposed that mental imagery is
functionally equivalent to vision.
• What he means by this is that mental
imagery uses the same internal
representations and processes that vision
does, but without visual input.
Could it be true?
• fMRI experiments indicate that the occipital
lobe and other early visual areas are active
during imagery tasks.
• Single-cell recording in monkeys shows that
areas activated during training for a task
also become activated when the monkey
simply “imagines” performing the task.
Which do you believe?