Ch 10 Flashcards
Perception
- Conscious sensory experience that comes from sensory input
- visual perception is one type
Mental Imagery
- conscious sensory experience in the absence of sensory input
- visual imagery is one type of imagery
- “perceiving” (seeing, hearing, smelling, etc.) in the absence of a stimulus
- Perception without the object actually being there
Is Imagery an important part of thinking?
- Aristole (350 BCE): “thought is impossible without an image”
- Introspection [late 1800s]:
- Galton: maybe not… (individual differences)
- Wundt: consciousness = images + sensations + feelings
- Behaviorism [1920s-1950s]:
- Watson: mental images are “mythological
Cognitive Psychology [1950s-present]
- Paivio (1963): memory for concrete vs. abstract words
-Two competing theories:
–Depiction (Kosslyn): imagery is like perception
– Description (Pylyshn): imagery is like language (propositions)
The imagery debate: Does mental imagery come from the same cognitive processes as perception? [Placeholder]
…
Spatial Representation (Depiction) Theory [Kosslyn 1975]
- Mental image is like a picture
- Same kind of representation as perception
Propositional (Description) Theory [Pylyshyn 1970]
Mental image is actually a set of rules describing the picture
- It might feel like perception, but it’s not
Introspection:
What does it FEEL like when you clod your eyes and envision the beach?
But introspection is too subjective… how can we MEASURE anything about mental imagery?
How to research imagery?
Introspection
- Francis Galton (1883): imagine your breakfast table…
–self-reports suggested people could inspect mental images as pictures
– Interesting variety of responses
- but: people may vary in how they translate their mental imagery into verbal reports!
- Chronometric studies measure TIME
– Procedure: form a mental image, then DO something with it
– DV: reaction time
Chronometric studies of imagery: Kosslyn (1976) Mental imagery vs. concepts?…
IV1: instructions
- Mental imagery (imagine picture of a typical cat)
- Concepts (think about cats) [semantic network]
IV2: type of true property
- high association, small size: Cat claws, Mouse whiskers, Alligator teeth…
should be a fast lookup for concepts (property at node), slow inspection for image (have to zoom in)
- high association, small size: Cat claws, Mouse whiskers, Alligator teeth…
- low association, large size: Cat head, Moues back, Alligator tail… should be a slow lookup for concepts (more links to traverse), fast inspection for image (big)
DV:RT
An early mental scanning study (Kosslyn, 1973)
Memorize the picture of a boat:
[picture goes away]
Now form a mental image of the boat
Focus on the anchor
Now look for the propeller
press the button when you find it
However
Proposition (description) theory: Hold up! you would get the same results from a propositional mental representation too
Mental Scanning
Image-scanning procedure, Kosslyn et al. (1978)
- Memorize this map
- Then we take the picture away
- Then “scan” from one landmark to another on the imagined map
– ex: imagine traveling from the well to
–
Mental Scanning Results
Imagined distance corresponds to real distance!
Spatial Equivalence
- Mental images seem to preserve the spatial layout and geometry of the perceived picture
Mental Zooming [Kosslyn 1975]
Imagine a rabbit next to a fly
Does it have a pink nose?
Imagine a rabbit next to an elephant
Does it have a pink nose?
Mental Rotation Shepard & Metzler (1971)
IV: how far you have to rotate on shape you compare to the other (degrees of rotation)
DV: reaction time
You have to find out if each pair of shapes: is it the same shape, or not?
The greater the angle, the longer the time it takes to decide
Mental imagery is like perception
Depiction theory vs Description theory
- Evidence seems to support
Depiction theory
