Video Module 25: Dual Coding

Question 1

dual code hypothesis

Answer 1

that our mental representations are picture-like for some tasks, and propositional for others
- we are able to encode material in more than one way (propositional and pictorial)

Question 2

What evidence supports the dual code hypothesis (Brooks, 1968)?

Answer 2

Brooks (1968) made a study which had two groups of participants:
1) participants memorised a block letter and memorised it; they then were asked to mentally travel the letter (visuospatial task)
2) participants saw a sentence and memorised it; they then were asked to classify each word as a noun (verbal task)

Both groups answered yes/no questions, but were asked to answer in 1 of 2 ways:
1) using a letter diagram of Ys and Ns (spatial response)
2) saying yes/no out loud (verbal response

• Brooks found that, when the representation task matched the response task in modality (verbal or spatial), RT was slower
  —This suggests that similar representations and tasks are more likely to interfere with each other
  —This suggests that different tasks use different representations

Question 3

What areas of brain are activated during mental imagery?

Answer 3

During mental imagery, both the early and higher visual areas active during actual perception are activated.
- evidence that mental imagery recruits the same areas for mental imagery and perception, but not evidence that mental imagery is the same as perception

Question 4

early visual areas

Answer 4

V1 (visual striate cortex) located in the occipital lobe
- active during mental imagery

Question 5

higher visual areas

Answer 5

• FFA (fusiform face area)
• PPA (parahippocampal place area)
• active during mental imagery

Question 6

visual vs. spatial imagery double dissociation

Answer 6

there is a double dissociation between the areas active during spatial imagery and visual imagery
- Explains why it’s possible for blind people to demonstrate the same amount of spatial awareness as sighted people, and why blind people will demonstrate the same performance on mental scanning and rotation tasks
—Mental scanning and mental rotation requires spatial imagery; mental scanning is a spatial location task, while mental rotation is a spatial transformation task

Question 7

How can researchers “read participants’ minds” by using imagery decoding?

Answer 7

In a study, researchers monitored participants’ brain activity while viewing Xs and Os by placing them in a scanner
—Researchers trained perceptual classifier programs to identify the pattern of activation in the brain associated with viewing either an X or an O, and found that during mental imagery, the classifiers could correctly guess what the participants were imagining (Xs or Os) about 62% of the time
- Activity patterns in the L lateral occipital region could predict what the subject was imagining about 62% of the time, which is significantly better than chance

Question 8

Can scientists read people’s dreams?

Answer 8

Not exactly, but yes. Scientists used a perceptual classifier program to monitor and collect data of people’s brain activity while they were dreaming. The perceptual classifier could then predict if there was a man in participants’ dreams with 70-80% accuracy.