Mental imagery (lec. 9)

Question 1

Why you should care about mental imagery?

Answer 1

• Imagery affects memory
• How does the brain store and represent data
• Imagery can improve your studying
• Imagery can affect your mental health
• Using your brain to understand how your brain work

Question 2

Mental imagery

Answer 2

Our ability to mentally recreate perceptual experience in the absence of a sensory stimulus. Perception, without sensation. It can be auditory, visual, tactile, or olfactory. You can also create mental images of stimuli that you have
never experienced.

Question 3

Dual-coding theory (Paivio, 1971)

Answer 3

Human knowledge is represented in two separate systems:
- Verbal: symbolic system, abstract (language system). Information doesn’t resemble what it stands for; abstract codes.
- Non-verbal: modality-specific system (based on sensory-motor information; image system). Images resemble what they stand for; analog representations. They maintain perceptual features of the stimulus they represent.

Question 4

Descriptive representation terms

Answer 4

• Non-Verbal Representation
• Analog Representation
• Depictive
• Modal
• Representations which maintain perceptual features of a stimulus (like a photograph)

Question 5

Abstract-code terms

Answer 5

• Verbal Representation
• Propositional Representation
• Descriptive
• Amodal
• Representations which have no direct connection to the features of a stimulus (like a computer code)

Question 6

The imagery debate

Answer 6

We know that people experience mental images and that there are many ways that imagery influences cognition.
What format or code does imagery take in our minds?
- Kosslyn (1994): Images are depictive representations (analog codes that maintain perceptual and spatial characteristics of objects)
- Pylyshyn (1973): Images are descriptive representations (symbolic codes that convey abstract conceptual information; do not resemble the real world)

Question 7

Descriptive Processing (Pylyshyn, 1973)

Answer 7

o Argues that knowledge is represented propositionally, via the manipulating of cognitive symbols.
o Argues propositional codes are the only requirement for thought: Imagery is an epiphenomenon
o Propositions: Can be verified as true or false, can be used to describe relationships between items

Question 8

Depictive vs. descriptive images

Answer 8

• If images are depictive (maintain perceptual and spatial characteristics), then people should process images and physical stimuli similarly
• If images descriptive, then mental processing would depend on the number of propositions instead of perceptual & spatial characteristics of stimuli

Question 9

Mental Scanning

Answer 9

Do mental images maintain the spatial characteristics of physical stimuli? If visual images are analog/depictive codes of physical stimuli:
- It should take more time to travel longer physical distances than shorter ones
- It should take longer to process larger mental distances than shorter distances

Question 10

Mental scanning experiment (Kosslyn, 1978)

Answer 10

Participants learned a map with landmarks. They were told to visualize one landmark and scan the mental image until they have ‘arrived’ at the target landmark. The time it took to mentally travel across landmarks increased with the “distance”. “Distance” between landmarks varied, but number of propositional properties between landmarks remained constant. This is evidence for depictive representation

Question 11

Mental Rotation, Shepard and Metzler’s (1971)

Answer 11

Investigated the time it took for individuals to rotate mental images of abstract figures. If mental rotation is similar to the rotation of real objects, then it will take individuals longer to mentally rotate a greater angular distance compared to a smaller angular distance. In experiments, participants saw 2 3D shapes and were asked if they were the same. In some trials, shapes were the same but had been rotated on the vertical axis (and in others, they were different shapes). Results demonstrated a linear
relationship between the amount of rotation of one of the shapes and the reaction time for participants to identify whether the shapes were the same. This is evidence for depictive representation.

Question 12

Mental scaling

Answer 12

When things get closer to you, they appear physically bigger until they fill your entire visual field. Kosslyn used the fact that bigger things are more “visible” in an experiment: Participants imagined animals standing next to an elephant or a fly. They were asked questions about the intermediary animal (e.g., does this cat have claws). Participants answered slower when the intermediary animal was paired with the elephant because they needed to
mentally “zoom in”. This was then replicated with “elephant-sized fly” and “fly sized elephant”. This is evidence for depictive representation

Question 13

Imagery and Perception

Answer 13

• Significant evidence for depictive representations in the brain
• If imagery is perception without sensation, then it follows that imagery and perception should use similar cognitive mechanisms
• Mary Cheves Perky tested this by having mental image stimuli (ex. “imagine and describe lemon”). Simultaneously participants were shown a very dim image of the same item
• Participant mental images matched features of the projection. Tthey reported not consciously perceiving the image
• This is evidence that imagery and perception utilize similar cognitive systems

Question 14

Imagery and perception, proof from interference

Answer 14

Segal & Fusella, (1970): Participants were told they would see a picture of an arrow, hear a note from a harmonica, or get nothing at all. Their task was to indicate what stimulus was presented while they were imagining either a tree or a telephone ring. Visual and auditory stimuli were presented at a very low intensity, making detection difficult. Detection rates for the visual stimulus were lower when imagining a tree, and rates for the auditory stimulus were lower when imagining a phone ring. If imagery uses the same mechanisms as perception, imagining a visual stimulus would ‘use up’
resources, decreasing detection.

Question 15

Imagery can facilitate perception

Answer 15

Farah, 1985: participants were shown a faint T or H and asked to create a visual image of T or H while detecting the projected eltter. Presenting congruent stimuli enhanced detection performance. This is further evidence that imagery and perception utilize similar cognitive system

Question 16

Motion aftereffects

Answer 16

Motion aftereffects result when sensory stimulation leads to perceptual overcompensation leading to the illusion motion in the opposite direction. Winawer et al., (2010) demonstrated that
mental imagery can create similar perceptual illusions. Participants “imagined motion in a single direction” for 60 seconds. This suggests that mental imagery activated the same visual processing neurons.

Question 17

Arguments Against Depictive Representations

Answer 17

Reed (1974) asked participants to memorize a shape which you could break down in different shapes (triangles, a diamond, etc.). Then, he asked participants if one of the shapes it could be broken down into (ex. a diamond) was part of the original shape. If mental images are depictive, they should easily be able to indicate if new shapes were part of the original from memory. In some cases, participants were able to accurately determine if shapes were new or part of the original image, but in other cases, accuracy was quite low. Results could be explained if participants were giving verbal labels to objects, instead of storing spatial characteristics.

Question 18

Arguments made against Kosslyn’s studies

Answer 18

Pylyshyn argues that because participant performance in experiments on depictive representation varied depending on task details, Kosslyn’s results only support their theory because that is what participants thought they were supposed to do.

Question 19

Types of interferences that could happen in an experiment

Answer 19

• Experimenter expectancy: Researchers inadvertently convey the anticipated results of the experiment to participants, altering behavior
• Demand characteristics: Participants form an interpretation of the researcher’s purpose and subconsciously change their behavior

Question 20

Imagery and the brain, neuropsychology findings

Answer 20

There is a lot we can learn from neuropsychological study of patients with brain lesions. Damage to a specific area can lead to deficits in one or more cognitive processes. For example:
- TC: had cortical blindness (damage to occipital and temporal lobes), and showed deficits in both perception and imagery abilities
- PB: cortical blindness (damage to occipital lobe), but was still able to perform visual imagery tasks
- Madame D: damage to occipital and temporal lobe, maintained some visual ability, and had such a good imagery that she used it to facilitate her perception

Question 21

Losing mental imagery abilities

Answer 21

There are also cases of individuals who lose mental imagery abilities but maintained perceptual abilities. For example, two patients sustained a closed-head injury. They couldn’t produce mental images or draw objects from memory. However, they had normal test result in memory, visual perception, and language.

Question 22

Limitations of neuropsychology + how to avoid them

Answer 22

• Generalized function loss
• Difficulty with instructions
• Damage to fibers of passage
  Newer brain imaging technology lets us examine the brain in real time while an awake participant performs a cognitive task. PET and fMRI allow us to compare activity in intact brains during mental imagery/perception tasks.

Question 23

Evidence From Neuroimaging

Answer 23

Neuroimaging results tend to support shared mechanisms between perception and imagery, although they are not exactly the same. For example, Kossyln recorded cell activity in the primary visual cortex (V1) while participants memorized pictures of black and white stripes and answered questions about the lines by visualizing the drawing. He found that viewing and imagining the stripes both activated V1 (PET), and that disrupting they were less accurate when V1 cells were disrupted (TMS).

Question 24

Neuroimaging,evidence for the roles of FFA + PPA in imagery

Answer 24

Research question: Is activity in the fusiform face are (FFA) and parahippocampal place area (PPA) similar in imagery vs perceptual tasks?Participants were shown famous faces and familiar buildings while in an fMRI machine. Results:
o FFA showed greater activity when viewing and imagining faces (vs buildings).
o PPA showed greater activity when viewing and imagining buildings (vs faces).
o An observer could determine if someone was viewing a face or building from brain activity.
This suggests that there are shared areas of perception and imagery.

Question 25

Neuroimaging: what distinguishes imagery and perception?

Answer 25

• Perception: higher-level brain areas (PFC) send top-down signals to perceptual processing areas.
• Imagery: a re-enacted perceptual experience where the same neurons are activated by frontal brain areas instead of a stimulus.
  Brain areas involved in planning, cognitive control, attention, and memory showed the most similarity in visual perception and imagery tasks (front of brain). There was limited similarity in in activity in V1 for the same tasks. This makes sense considering no visual stimulus is present during imagery tasks.

Question 26

The imagery debate nowadays

Answer 26

The imagery debate is not solved, but most researchers agree that imagery:
o Is a combination of depictive and abstract proposition
o Arises from similar brain mechanisms as perception
Regardless of its nature, imagery impacts cognitive functioning and behavioral manifestations, which is what a lot of research focuses on today.

Question 27

Imagery and memory

Answer 27

Imagery is beneficial to memory. Memory is better when items are stored as pictures compared to words. This is especially true for interactive images. This finding produced an outcome called the Picture Superiority Effect. Paivio and Csapo asked participants to either:
- read words or to say the name of a picture out loud (verbal
condition)
- Imagine a visual image of the words and
pictures (imagery condition)
They were then given a surprise memory test. They found that image memory was better than word memory.

Question 28

Dual-Coding Theory and the Picture Superiority Effect

Answer 28

When we see a picture, we automatically create a visual representation and give it a verbal label. But when we read a word, we
only generate the verbal label. Image-based memory uses two codes (images and labels) instead of one (just labels).

Question 29

The concreteness effect

Answer 29

Concrete words are remembered better than abstract words:
- Concrete words: easier to iamgine, more likely to spontaneously create visual images
- Abstract words: harder to visualize, so we rely only on one verbal code (labels)
An experiment showed that the concreteness effect only happened when participants were not presented with an interfering stimulus.

Question 30

Imagery and Mental Health, experiment by Holmes (2005)

Answer 30

Participants listened to short descriptions of possible events with positive and negative outcomes. Participants were placed into 2 groups:
- Imagery group: imagine visual images of the scenario
- Meaning group: focus on the meaning of the words
They found that the participants in the imagery group had higher rates of anxiety.

Question 31

Imagery and PTSD

Answer 31

Negative intrusive imagery is a characteristic trait of individuals with PTSD. Re-experiencing traumatic events involving involuntary and unwanted memorie. People will respond as if they are re-experiencing the event (changes to the autonomic nervous system, increased heart rate and sweating, re-enacting behaviors…). People with more vivid imagery are more likely to experience intrusive images after negative events

Question 32

Anxiety Disorders and imagery

Answer 32

Intense, persistent, and excessive worrying that interferes with daily life (Generalized/Social Anxiety and
phobias) are associated with an increase of negative imagery of future events,
which they believe can happen, exacerbating anxiety

Question 33

Depressive disorders and imagery

Answer 33

Persistent feelings of sadness, frequently accompanied by a loss of interest are associated with an increase of negative imagery, specifically suicidal ideation. They are also associated with a decrease in positive imagery

Question 34

Imagery Rescripting

Answer 34

A technique to help treat mental disorders linked to abnormal mental imagery:
- Patients are guided through memories of past negative events.
- Instructed to imagine themselves acting the way they wish they could have during the event (protecting their younger selves, others, etc.)
- Goal: replace negative memories with positive ones
- Imagery rescripting has successfully been used to treat mental heath disorders. Treatments that focus on imagery have the highest success rate of treating PTSD

Question 35

Galton breakfast study

Answer 35

Galton (1880) asked a group of scientists to describe their breakfast. He found that some gave vivid description and others reported no mental imagery at all. This showed that individuals vary greatly in their ability to create mental images.

Question 36

How do we measure mental imagery?

Answer 36

• Self-report: Asking people to write or explain their imagery experiences. Vividness of Visual Imagery
  Questionnaire (Marks, 1973: 1-5 Likert
  Scale assessing vividness of imagery,
  testing object imagery).
• Objective performance task: Paper Folding Test (Ekstrom, 1976): Participants view diagrams of paper being folded and hold punched. Participants must ‘mentally unfold’ the paper and identify the placement of the holes (testing spatial ability).

Question 37

Aphantasia

Answer 37

Some people cannot form mental images at all. For example, patient MX claimed to have lost all ability to form mental images following heart surgery. He scored as low as possible on the Vividness of Visual Imagery Questionnaire. MRI showed his visual cortex and fusiform gyrus were inhibited. After learning of MX others reported that they had never been able to use visual imagery. They described their experience as “the shape of an apple if you felt it in your hands in the dark” and “thinking only in radio”. The condition became known as Congenital Aphantasia and affects 1-3% of the population.

Question 38

Hyperphantasia

Answer 38

Those who experience extremely vivid visual imagery. Although little is known about this population, and it is likely much rarer.

Question 39

Mental imagery ability and professional occupation

Answer 39

• Those with aphantasia are more likely to become mathematicians and scientists
• Those with hyperaphantasia are more likely to occupy a creative procession.