Lecture 12: Imagery

Question 1

What is imagery?

Answer 1

Broadly defined as the ability to recreate* a
perceptual experience in the absence of an external sensory stimulus
*However, you don’t need to have experienced something to imagine it
* It can be a recreation, you don’t have to have experienced something in order to have imagined it. Create an image that does not necessarily exist in the world.3

• Creating a scene with your mind
• Setting a scene
• There are a lot of mental elements that go in imagery (sound, smells) not just images.

Question 2

Qualities of imagery: Vividness

Answer 2

Vividness typically refers to how clearly we can create an image in our mind’s eye
ex: asked to imagine a house - how much detail are you able to imagine this image in. Vividness really varies with individuals.

How vivid are mental images?
◦ Varies across individuals and contexts
◦ Familiarity may enhance vividness of mental images (Baddeley & Andrade, 2000). Ex: someone who really likes cars vs someone that is not so interested will imagine a ferarri in much more detail then someone who is not so interested in cars.
◦ Musicians seem to hear musical imagery more often than non-musicians (Beaty et al., 2013) - musical imagery in head to feels real (like a radio is on)

Question 3

Individual differences in imagery

Answer 3

In class, we have discussed vision as being one of our dominant senses… does this also hold for imagery?
◦ When recalling past personal events, some people tend to do this primarily with visual images and others with words
◦ We can compare use of different types of imagery across these “visualizers” and “verbalizers”.
- Visual imagery is the same in visualizers and verbalizers
- Auditory imagery is greater in verbalizers than visualizers. These are individual differences in how people are using imagery.

Question 4

Dual-Coding Theory (Paivio, 1971)

Answer 4

◦ Breaks down the mental representation of events into two categories (image and word)
- Verbal system: events are represented through language and component parts.
- Non verbal system: Instead of word, you think of a specific cat.

Question 5

Dual-Coding Theory (Paivio, 1971)

Answer 5

◦ There are some exceptions, like onomatopoeias where the word resembles the sound; however, these also vary across languages

English: hahaha
Spanish: jajaja
Portuguese: kkk
Using a verbal code but is also resembling what it represents and sounds but the verbal code changes across languages.

Question 6

Dual-Coding Theory (Paivio, 1971)

Answer 6

◦ While this theory was useful for thinking about imagery, it was proposed as a theory for how we represent thoughts more generally…
How do we represent mental images?

Question 7

The imagery debate

Answer 7

There are two opposing viewpoints for how we form representations of mental images:
1. Stephen Kosslyn: Imagery is an analogue form of representation. The image that we form in out minds eye preserve the features of what they represent - maintain the percept of what it represents.
2. Zenon Pylyshyn: Imagery is a byproduct of a symbolic code. Represent it in propositions that represent this image (linguistic code).

Question 8

The imagery debate

Answer 8

Pylyshyn’s Propositional Theory
(add image)

Question 9

The imagery debate

Answer 9

Kosslyn’s Depictive Representation Theory
(add image)

Question 10

The imagery debate: Evidence from mental scanning

Answer 10

Reaction time is related to time required to scan a mental image (Kosslyn, 1973)
* Ask them to scan from roots to petals vs scan them from roots to leaves.
- roots to leaves will take less time (conserving image)
- roots to petals take more time.

* Might instead be searching through a list of features: petals, stem, leaves, soil, roots. 
  - same idea
  - Searching the list we created 
  - takes longer to go through list when going from petals to roots.

Question 11

The imagery debate: Evidence from mental scanning

Answer 11

◦ Kosslyn, Ball, and Reiser (1978) had participants scan a memorized map where the number of landmarks was the same but the distance varied
◦ Again, the further the scanning distance the longer the reaction time
- the time is takes us is dependent on location (evidence for mental scanning supporting depicting theory)

Question 12

The imagery debate: Evidence from
mental rotation

Answer 12

The time to respond is positively related to the amount the image must be rotated
- to determine if two images are the same
- requires mental manipulation of the image, rotate the image on the right to compare it to the left.
- The time to respond and say whether it is the same or not, is positively related to the amount of rotation.
- The moreI have to rotate the image, the longer it will take

Question 13

The imagery debate: Evidence from mental scaling

Answer 13

◦ Kosslyn (1975) asked participants to imagine certain features of the animal
◦ Scale of the animal was small or large in comparison with a second animal
- takes longer to respond to a question about the animal when the scale is smaller than the other animal’s scale.

Question 14

Imagery versus perception

Answer 14

We’ve seen extensive evidence suggesting that imagery is an analogue form of representation, preserving features of percepts
1. Is behavioural performance on tasks with mental images and percepts similar? This would suggest that they are similar and share similar features
2. Do similar brain mechanisms support imagery and perception?

Question 15

Imagery versus perception (study)

Answer 15

*Crowder (1989) conducted a series of experiments examining participants judgements of musical tones
- played participants a tone by a particular instrument
- Played a second tone: could be from guitar (same instrument) or different instrument.
* Participants were faster at responding when the tone was played by the same instrument. It is still taking longer but the effect isn’t as strong as the perceptual task. Shows that auditory imagery and auditory perception share some mechanisms but they are not completely the same.

Question 16

Auditory imagery versus perception

Answer 16

1) People are presented with a pure tone (single frequency, no harmonic spectrum), and are asked to imagine this tone played by a specific instrument (guitar, flute, or trumpet)
2) People are presented with a second tone played by one of three instruments (guitar, flute, or trumpet)
3) People judge whether the second tone is the same as or different from the first tone

Same experiment but rather than having the 1st tone played by an instrument it is imagined.

If auditory imagery is similar to perception, what results should we expect? Same as what happened as perception.

Question 17

Auditory imagery versus percept (study)

Answer 17

People were faster at saying that two notes were the same when the perceived timbre was consistent with the heard timbre.
- Faster when the two instruments were consistent with each other.
- effect is not as strong as the perceptual task. Not completely the same.

Are similar brain areas active during auditory imagery as during auditory perception? Do they share similar neural networks?

Participants either listened to or imagined sounds inside an fMRI scanner
1) Perception: Sound of the instrument with its corresponding name on the screen presented to participants
2) Auditory Imagery: Participants imagine sounds corresponding to the instrument name presented on the screen

They wanted to look if there is some overlap in the brain activity during these two tasks.
- we see activation of auditory cortex (we are hearing a sound so it makes sense). We don’t expect them to be the exact same thing but they do share some mechanisms.
- overlap in the regions active (auditory areas active during both the tasks)
- overlap in the neural mechanisms supporting those tasks.

Question 18

Visual imagery versus perception

Answer 18

Kosslyn et al. (1999) showed that visual imagery and perception tasks evoked activity in primary visual cortex
- If people are seeing this visual images or imagining them, in both cases there is activity in primary visual cortex that is active in both these tasks.

Question 19

Evidence against depictive representations

Answer 19

If imagery is a depictive representation, participants should easily be able to identify components of memorized images
This is not actually the case… the accuracy at which people identify the different components of the image is low.
- evidence agains depictive representation

Question 20

Evidence against depictive representations

Answer 20

There is also evidence from patients with brain damage that imagery may not entirely rely on the same neural mechanisms
- what we see is that there’s a ceiling effect, essentially for the imagery task. So this person shows no deficits on imagery, but they do show show deficits on perception. So this is suggesting that the lesion, the particular lesion they have it may not necessarily be involved or as important in imagery, but it’s very important in perception
- So there’s not a complete sort of 1 to 1 mapping between imagery and perception.

Question 21

Imagery and memory

Answer 21

Ex: Piano. When you are playing the piano you have perceptual feedback (tactile and aufdtory)
What happens when we remove the feedback and force them to play relying only on tactile or auditory perception?
1) Normal performance feedback
Play normally through the piece of music
2) Motor only performance feedback
Play through the piece of music without hearing the performance, imagine what it sounds like
3) Auditory only performance feedback
Hear the piece of music, imagine what the movements feel like
4) No performance feedback
Imagine what the piece of music sounds like, and what the movements feel like

Question 22

Imagery and memory (result of study)

Answer 22

Memory performance decreases as feedback available at practice decreases.

Low on Auditory Imagery (white bars):
- Memory performance decreases as feedback available at practice decreases
- It is difficult to compensate when you don’t have the sound.

High on Auditory Imagery (black bars):
- Auditory imagery compensates for lack of feedback, not as much of a decrease in performance.
- They are able to compensate for the lack of feedback with their auditory imagery. They perform better (normal and motor is pretty much the same for people with high auditory imagery).

Question 23

Imagery and memory

Answer 23

Items represented as images are better remembered than those represented as words (Paivio & Csapo, 1973)
- hard to represent the word “idea” as a visual image
- items represented as images are easily imagined and are remembered better than words.
- You can actually disrupt this enhancement of memory with imagery. The idea is that the dynamic visual noise that you’re watching is actually disrupting your imagery processes. So you’re not able to visually imagine the image and so you actually don’t see this enhancement.

Question 24

Imagery and mental health

Answer 24

Negative imagery seems to be linked to severity of several psychological disorders, including depression, anxiety, and post -traumatic stress disorder.
- Tendency towards negative imagery. Ex: generalized anxiety disorder (rumination), PTSD (flashbacks - imagery of prior events)
- negative imagery is linked to mental health.

Question 25

Interesting cases of imagery: Synesthesia

Answer 25

A Reminder…
◦ Synesthesia is a sensory experience in which a stimulus in one sensory modality also invokes a response in one or more other sensory modalities
◦ Chromesthesia is the most common experience among synesthetes

Question 26

How does synesthesia influence memory?

Answer 26

◦ Synesthesia may aid memory in specific cases
◦ Participants with chromesthesia and absolute pitch have reported that their chromesthesia aids their memory for specific pitches and music (Rogers, 1987)
-absolute pitch = ear a pitch and now exactly what pitch it is.

Question 27

Interesting cases of imagery: Amusia

Answer 27

Amusia: deficits in musical abilities; also called tone-deafness
◦ People with amusia have been shown to have deficits in visual/spatial imagery
◦ Imagery in different sensory domains may interact with one another

Mental rotation: musicians and non musicians perform equally. Amusic participants have a high percent error. We see this imagery deficit as linked to other kinds of more perceptual deficit and tone deafness. The higher the severity of tone deafness, the more errors made with mental rotation task. No relationship for people that are tone deaf.

Animal matching: