Mental Imagery Flashcards
Mental Imagery
Our ability to mentally recreate perceptual experience in the absence of a sensory stimulus
-You can also create mental images of stimuli that you have never experienced
Dual-Coding Theory (Paivio, 1971)
Human knowledge is represented in two seperate systems:
1. Non-Verbal
2. Verbal
Non-Verbal System
Modality Specific System (based on sensory-motor information; image system)
-Images resemble what they stand for analog representation
-Maintain perceptual features of the stimulus the represent
Verbal System
Symbolic System, Abstract (language system)
-Information does not resemble what it stands for….a.k.a. abstract codes
Depictive Representation Terms
-Non-verbal representations
-analog representations
-depictive
-modal
-representations which maintain perceptual features
-E.g. a photograph
Abstract-Code Terms
-verbal representations`
-propositional representation
-descriptive
-amodal
-representations which have no direct connection to the features of a stimulus
-E.g. computer code
What format or code does imagery take in our minds?
The debate…
Kosslyn (1994)
Images are depictive representations
-Perserve perceptual and spatial information
-When you do mental imagery, you’re bringing the representation to mind
-E.g. imagining the image of an apple in your mind
Pylyshyn (1973)
Images are descriptive representations
-Does not preserve perceptual and spatial information
-Images as epiphenomenon: when you do mental imagery you hallucinate images as as an effect of accessing the information
-E.g. Apples are fruit. Apples are round.
Epiphenomenon
A mere by-product of a process that has no effect on the process itself
-E.g. Ice-cream sales go up in the summer… so do murder rates. No correlation. Just an…
Descriptive Processing (Pylyshyn, 1973)
-Argues that knowledge is represented propositionally, via the manipulating of cognitive symbols
-Argues propositional codes are the only requirement for thought
-Propositions can be verified as true or false + can be used to describe relationships between items
-E.g.The lamp is to the left of the books
process images and physical stimuli similarly (perceptual and spatial characteristics)
If images are depictive then people should…
depend on the number of propositions
If images are descriptive , then mental processing would…
Mental Scanning (Kosslyn, 1973)
-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
The time it took to mentally travel across landmarks increased with the ‘‘distance’’
Kosslyn 1978. Evidence for depictive representation.
Shepard and Metzler’s (1971)
Investigated the time it took for individuals to rotate mental images of abstract figures
Theoretical Framework
If mental rotation is similar to the rotation of the real objects, then it will take individuals longer to mentally rotate a greater angular distance compared to a smaller angular distance
Mental Rotation
The more the image is rotated, the more time it will take to rotate it back
-linear relationship
-Evidence for depictive representation
Mental Scaling
When things get closer to you, the appear physically bigger until they fill your entire visual field
-Slower to answer a question when you have to mentally zoom-in
-Faster to answer question when the image is already zoomed-in
Imagery and Perception
If imagery is perception without sensation, then it follows that imagery and perception should use similar cognitive mechanisms
-Evidence that imagery and perception utilize similar cognitive systems
-Evidence for shared perception and mental imagery system from interference
sensory stimulation leads to perceptual overcompensation leading to the illusion motion in the opposite direction
Motion afteraffects result when…
Reed (1974)
-If mental images are depictive, they should be easily be able to indicate if new shapes were part of the original from memory
-In some cases accuracy was quite low
Arguments against depictive representations
Experimenter Expectancy
Researchers inadvertently convey the anticipated results of the experiment to the participants, altering behaviour
-Arguing against depictive representations
Demand Characteristics
Participants form an interpretation of the researcher’s purpose and subconsciously change their behaviour
-Arguing against depictive representations
Intons-Peterson, 1983
Demonstrated that experimenter expectations can directly influence participant responses on imagery experiments
Evidence from Neuroimaging
-Kosslyn (1999)
Demonstrated that viewing and imagining the stripes both activated V1 (PET), and that disrupting they were less accurate when V1 cells were disrupted (TMS)
Evidence from Neuroimaging
-O’Craven & Kanwisher (2000)
-FFA showed greater activity when viewing and imagining faces (vs. building)
-PPA showed greater activity when viewing and imagining buildings (vs. faces)
Evidence from Neuroimaging
-Ganis et al., 2004
-Brain areas involved in planning, cognitive control, attention, and memory showed the most similarity in visual perception and imagery tasks
-There was limited similarity in activity in V1 for the same tasks… this makes sense considering no visual stimulus is present during imagery tasks
Evidence from patients with Brain Damage
-Policardi et al., 1996
-Damage to the occipital & temporal lobes
-Lost ability to distinguish light from dark
-Lack of head movements and blinking when observing objects in motion
-Loss of conscious vision was associated with loss of mental imagery
-Could not provide visual descriptions of familiar places, tasks, or objects
-Deficits in both perception and imagery abilities
Evidence from patients with Brain Damage
-Zago et al., 2010
-Damage to occiptal lobe
-Able to perform visual imagery tasks
Evidence from patients with Brain Damage
-Bartolomeo et al., 2010
-Damage to occipital & temporal lobes
-Could copy drawings but was not able to read or recognize objects or faces
-Able to perform mental imagery tasks
-If she could not recognize an object at her home, she would visualize it to help her identify items
-Imagery facilitated perception!
Evidence from patients with Brain Damage
-2 patients sustained closed-head injuries
-Loss of mental imagery abilities but maintained perceptual abilities
-Could not produce mental images
-Neither could draw animals or objects from memory
-Tested normally on, visual perception, memory, language
Imagery and Mental Health
-Holmes et al., 2005
Negative imagery group reported higher levels of immediate anxiety
-Imagery group : imagine visual images of the scenario
-Meaning group : focus on the meaning of the words
increase of negative imagery of future events, which they believe can happen, potentially exacerbating anxiety
Anxiety Disorders
Intense, persistent, and excessive worrying that interferes with daily life (generalized/social anxiety and phobias) associated with an…
an increase of negtive imagery, specifically suicidal ideation + a decrease with positive imagery
Depressive Disorders
Persistent feelings of sadness, frequently accompanied by a loss of interest associated with…
Imagery Rescripting
Successfully been used to treat mental health disorders and treatments that focus on imagery are amongst the most effective treatments for PTSD
-The goal is to replace negative memories with positive ones
Galton (1880)
Asked a group of vary greatly in their ability to create mental images…
-Some gave vivid descriptions
-Others reported no mental imagery at all
-Self-report
-Objective Performance Tasks
How do we measure mental imagery?
Aphantasia
Some people cannot form mental images at all
-Visual cortex + fusiform gyrus were inhibited
-More likely to become mathematicians and scientists
Congenital Aphantasia
Some people have never been able to use visual imagery
Hyperphantasia
Those who experience extremely vivid visual imagery
-More likely to occupy a creative procession
ultimately separable cognitive processes
Mental imagery and perception are similar but…
not entirely the same
Mental imagery and perception activate similar brain regions but..
