Mental Imagery Flashcards
propositional representation
a language-like representations
aka “symbol”
depictive representation
an image that is similar to the experience of that image in real life
key question about mental imagery
is the representation that underlies imagery propositional or depictive?
interference effects
if perception and imagery tasks interfere with each other, then they must require the same mental system
Kosslyn image scanning experiment
subjects memorize a drawing, then image it when it is taken away
results of the Kosslyn experiment
longer distance between two items in mental images lead to slower reaction times
critiques of the Kosslyn experiment
there may be a propositional way to scan images
subjects may infer the experimenter’s demands and behave accordingly
image zooming task
imagine a detail, then press a button
results of the image zooming task
it takes longer to imagine a detail when you have to “zoom in” to see it
Shepard mental rotation experiment
subjects were shown two objects and had to say whether the objects were a rotation of the first, or were non-identical objects
results of Shepard mental rotation experiment
when objects are separated by degrees of rotation, a larger degree of rotation leads to a slower reaction time
differences between imagery and perception
- perception has a metric, images don’t have that
- it’s hard to perceive the exact quantitative relationships in mental images
- it’s hard to change the mental image of an ambiguous figure once one thing is seen, but it’s easier to do this when an image is directly perceived
compromise theory
a basic code is propositional for long-term storage
a propositional code is used to create depictive images depictive image can be scanned, zoomed, and further edited
evidence for the compromise theory
image generation experiments
image generation experiments
memorize grid letter, then image a letter, and determine whether an “x” falls on the letter
results of the image generation experiments
uppercase letter with more segments take longer to image
faster responses are given when the “x” falls on the segment drawn first than when it falls on the last segment
what does the compromise theory predict?
the visual cortex will be used for imagery
fMRI
- uses the blood-oxygen dependent (BOLD) signal
mental activity > neural activity > increased oxygen needs > more oxygen in the blood > stronger BOLD response
results of an fMRI imagery experiment
when only looking at an image on the screen, the visual cortex is only activated by the perception
when looking at an image and alternating it with imagining, the visual cortex is activated by both perception and imagining
