Visual Imagery I: Internal and External Perception

Question 1

Mental imagery?

Answer 1

Re-creating the sensory world in the absence of physical stimuli

Question 2

Visual imagery?

Answer 2

Seeing in the absence of a visual stimulus

Question 3

Do you think in words or images?

Answer 3

Wundt: Images are one of three basic elements of consciousness (with sensations & emotions)

Aristotle: “It is impossible to think without an image”

• Words have the power of specific meaning
• Images have the power of holistic meaning, power of metaphor

Question 4

Imageless thought debate?

Answer 4

Galton (1883) observed people who struggled with visual imagery, but thinking was not affected

Behaviourism discounted this question, but questions were revisited in cognitive revolution

Question 5

Alan Paivio’swork? Picture superiority and Conceptual peg hypothesis

Answer 5

“picture superiority”:
Memory for images of objects stronger than memory for names of objects

• Concrete nouns remembered better than abstract nouns

Conceptual peg hypothesis (will be on exam): images have many places for other stimuli to “hang” onto

Question 6

Advancements in Experimental Design?

Answer 6

• Infer mental processes, including imagery
• Mental chronometry: measuring time to complete cognitive tasks

Question 7

Imagery vs. Perception?

Answer 7

Do they work in the same way? - Same mechanisms?

Perception is spatial, sizes/distances vary. Is imagery spatial, too?

Question 8

Mental Scanning - Kosslyn’sinitial mental scanning study?

1. Memorize an image
2. Imagine it, focusing part A
3. Mentally scan across the image, look for B
4. Respond if B is in the image or not

Answer 8

Logic: if imagery is spatial, distance between A and B should predict time to find B

Result: people took longer to “find” parts further away from focus

Possible confound:
- People get distracted by things between A and B
- Time doesn’t reflect spatial distance but number of things in between

Question 9

Mental Scanning - Are the mental images really coded spatially?

Pylyshyn(1973) argued spatial representation is an epiphenomenon

Answer 9

Epiphenomenon:
Imagery is mostly propositional

The debate between depictive vs. descriptive imagery continues

Question 10

Imagery and Perception Similarities?

Answer 10

Level of detail increases as distance decreases

Image a car from a far versus up close

Question 11

Level of Detail Study (Kosslyn, 1975)?

Participants told to imagine two objects

IV:
a) Target object next to a larger object
E.g.: rabbit next to elephant
b) Target object next to a smaller object
E.g.: rabbit next to fly

Once imagined, participants asked about details of the target object
E.g.: “Does the rabbit have whiskers?”

DV: response time

Answer 11

Results: participants took longer to evaluate details when target was relatively small

Findings suggest that detail is limited by size in visual imagery, as in visual perception

Question 12

Interaction between Perception and Imagery -

Perky (1910) showed participants a blank screen, and asked them to imagine objects

At the same time, very dim image of the object appeared on the screen?

Answer 12

Results

• Participants reported features of their mental image that matched projected image
• Imagination was implicitly biased by perception

Question 13

Interaction between Perception and Imagery - Martha Farah

Participants asked to visualize an H or a T (only one)

Then two squares flashed on screen (either H or T)
- Non-simultaneous flash (serial presentation)

Task: which square (1stor 2nd) contained letter?

Answer 13

Results showed more accurate target detection when imagery matched target

Suggests perception & imagery shared mechanism

Perception and Imagery facilitate each other