Lecture_10_Imagery Flashcards
Modality of Mental Imagery
- Visual
- Auditory
- Tactile
- Olfactory
- Gustatory
- Kinesthetic, Somatic, Motor
Visual Imagery
Subjectively feels like “seeing with the mind’s eye”
- I.e., a controlled mental process
Visual Imagery Differences to Perception
- Consciously aware of deliberately forming visual images
- Contain much less detail (e.g., lacking sharp edges and borders)
- Weaker, fuzzier form of sensory perception
- Different brain areas
Mental Representation
Outside of conscious awareness
- Visual imagery can be both conscious and unconscious
Hallucinations
Perception-like experiences in the absence of environmental stimulations
- but are perceived/believed to be reality
- Is not mental imagery
Characteristics of the Visual Imagery System
- Image generation
- Image inspection
- Image maintenance
- Image transformation
Mental Rotation Task
Determining whether 2 patterns are identical
- Evidence for mental image transformation
- Reaction time (RT) increases with rotation angles
- Same RT for both 2D and 3D
Implications of Mental Rotation Task
- Mental representation resembles a picture, not a verbal concept.
- Linear-relationship in results
suggests a single process. - A separate representation system - Imagery
How does imagery work?
Is visual imagery a separate representation system?
The debate between depictive and propositional representations
Alan Paivio’s Dual-Coding Theory
2 major ways to represent concepts
1) Verbal representations
2) Visual images
▪ A concept can vary along the concrete-abstract dimension
➢ How easy or hard is it to create a mental image?
➢ e.g., flower vs. kindness
▪ Concrete concepts have both verbal + image representations (hence, ‘dual coding’),
but abstract concepts only have verbal
➢ Two is better than one → concrete concepts should be remembered better
Concrete-Abstract Dimension
Flower vs. kindness
- Concrete concepts have both verbal + image representations (hence, ‘dual coding’),
- Abstract concepts only have verbal
- Two is better than one: concrete concepts should be remembered better
Which condition(s) did p’s remember the best and the worst?
A) Concrete-concrete
B) Concrete-abstract
C) Abstract-concrete
D) Abstract-abstract
- The best: concrete-concrete
- The worst: abstract-abstract
Depictive Representations
Resembling a picture
- Visual imagery resembles visual perception
- Objects within it are organized spatially
- Distances among parts in the representation correspond to actual distances
Propositional Representations
A non-spatial, language-based representation of an idea or event
- Visual imagery relies on implicit knowledge, and differs from visual
perception
- Verbal, language-based
- Proposition = abstract, basic unit of meaning that has a truth value (true/false)
- May also account for the data
Evidence that imagery resembles visual perception
Mental scanning task
- Memorize a map, then later asked to scan the mental image
- Manipulated distance between items in the image
- Distance between items predicted RT
Depictive Vs. Propositional Representation Debate
Evidence favors depictive theories as being more parsimonious
Principle of Parsimony
Simplest: “Being careful. What else can explain the situation?”
- Depictive representation
Epiphenomenon
A perfectly real phenomenon that is
merely a by-product of the process
- Spatial travel through a mental image, OR accessing greater number of links in a proposition?
- Propositional representation
Evidence that Imagery Does Not Resemble Perception
Favoring propositional theories
- Abstract animal rotation task showed participant struggled to see rotated image
2nd Evidence from mental scanning task
Favoring depictive theories
- Prediction: If mental images are represented spatially, then physical features would not be represented if the image is very small
- Mental zoom rather than use proposition or knowledge
- Relative size of animal predicted RT
Neuroimaging Studies
Favoring depictive theories
- Visual mental-imagery tasks activate visual cortex areas (supporting perception), rather than areas known to support language
- Visual buffer -> Attention window -> Other brain areas
Visual buffer
A brain area in the early visual cortex: short-term storage for visual information in perception and imagery
Attention window
Selects some visual information in this buffer, and passes it onto other brain areas for further processing
Image creation
Vision in Reverse
Visual Processing
- Bottom-up
- Triggered by a visual stimulus
1. Occipital lobe ->
2. Temporal lobe (‘what’) or Parietal lobe (‘where’)
3. Frontal lobe
Imagery Process
- Top-down
- Sensory-memory recall
1. Frontal lobe
2. Temporal lobe
3. Parietal lobe
4. Occipital lobe
Frontal Lobe
Organizing and coordinating sensory and spatial brain areas
Temporal Lobe
Retrieving representations stored in memory
Parietal Lobe
Spatially manipulating the imagery representation
Occipital Lobe
Eliciting a conscious, visual perception-like experience
Individual Differences in Visual Imagery Experience
Strength and Vividness of Imagery Content
1) Self-report
2) Neuroimaging data
- Excitability of the visual cortex correlates with imagery strength
- Not trait-like, but likely to change moment-by-moment
Aphantasia
Absent vividness
- Difficulty with face recognition and autobiographical memory
- Deficit in voluntary imagery, but claim to still dream visually
Hyperphantasia
- Real seeing vividness
- “Eidetic” or “photographic” imagery
- Synaesthesia (“merging of the senses”)
- E.g., experience colors when listening to music, or perceive tastes when looking at words
