Final _ chapter 10 Flashcards
Visual Imagery
Seeing in the absence of a visual stimulus
Mental Imagery
A broader term that refers to the ability to re-create the sensory world in the absence of physical stimuli
- used to include all of the senses
Wundt and imagery
- Wundt proposed that images were on of the three basic elements of consciousness [+sensations & feelings]
- Proposed that because images accompany thoughts, studying images was a way of studying thinking.
Imageless thought debate
- Some took Aristotle’s side that ‘thought is impossible without an image’
- Others that thinking can occur without images
Francis Galton 1883
- Evidence supporting that imagery was not required for thinking
- Observed that people who had great difficutlty forming visual images were still quite capable of thinking
Behaviorism and imagery
Beleived they weren’t worthy of study
- Arguments and counterarguments ended when behaviorism took central place in psychology
- Branded the study of imagery as unproductive since visual images are invisible to everyone except the person experiencing them.
Changed when the study of cognition was reborn
Paired-Associate Learning
Method
- Participants are presented with pairs of words[study period]
- They are then presentedwith the first word of each pair[test perios]
- Their task is to recall the word was paired with it during the study period
Conceptual Peg Hypothesis
Alan Paivio’s [1963]
- Use paired-associate learning
- Showed that it was easier to remember concrete nouns that can be imaged than it is to remember abstract nouns
- Since concrete nouns create images that other words can ‘hang onto’
Shepard and Metzler 1971
Mental Rotation Experiment[From Chap 5]
- First to apply quantitative methods to the study of imagery
- Using mental chronometry (amount of time it take to carry out a mental task)
- Found that we rotate images in our mind by placing two structures side by side and asking participants if they’re the same of different.
Showed that the spatial experience for both imagery and perception matches the layout of the actual stimulus
Stephen Kosslyn [1973]
Mental Scanning
- Asked participants to memorize a picture of an object
- Then to create an image of that object in their mind and to focus on one part
- They were then asked to look at another part
- And to press the ‘true’ button when they found this part or the ‘false’ when they couldn’t
It took longer for participants to find parts that are located further from the initial point because they would be scanning the mental image
- Took it as evidence for the spatial nature of imagery
proposed Spatial/Depictive Representation
Glen Lea [1975]
Proposed that as participants scanned, they may have encountered other intresting parts, and this distraction may have increased reaction time
- To counter, Kosslyn asked participants to scan a map that contained seven different locations
- Participants were then asked to scan between every possible pair of location
- The results were still the same
Zenon Pylyshyn [1973]
Started Imagery debate[spatial vs propositional]
- Beleived that experienced imagery as spacial is but an epiphenomenon that accompanies the real mechanism.
- Mechanism underlying imagery involves propositional representations in which relationships can be represented by abstract symbols such as equations or statements.
- Proposes that imagery operates in a way similar to the semantic network, with distance depicted by lines between nodes rather than visual space.
Proposed Propositional Representation
Size in the visual field
Kosslyn [1978]
- Asked participants to imagine two animals next to each other
- first to imagine they were standing close enough so that the larger animal filled most of their visual field
- he then asked a question about the animal that wasn’t focus and to answer the question as fast as possible
- then did the same but with the other animal in focus
[results]
-Participants aswered questions about the animal in focus faster
In a mental walking task, participants equated distance between then and the animal to their actual size they way they would in real like
- Further evidence for the idea that images are spatial just like perception.
Imagery and Perception interacting
Perky [1910]
- The participant’s descriptions of their images matched the dimed images that perky was projecting in front of them.
Segal [1960]
- Found that participants would notice the projections if they weren’t asked to visualize something at the same time
Farah [1985]
-Indicated that target letter was detected more accurately when the participants had been imagening the same letter rather than a different one.
Perky Effect – visual imagery interferes with perception
Recording from a single neuron in humans
Method
An electrode is planted in patient’s brain and then monitored over a period of a few days
- Experiements make it possible not only to record neural responses to stimuli
- but also to study how these neurons respond when the patients carry out cognitive activities such as imagening and remembering.
Recording from a single neuron in humans
Method
An electrode is planted in patient’s brain and then monitored over a period of a few days
- Experiements make it possible not only to record neural responses to stimuli
- but also to study how these neurons respond when the patients carry out cognitive activities such as imagening and remembering.
Kreiman et al. 2000
Imagery neurons
- Studied patients who had electrodes implanted in various areas in their medial temporal lobe
- found neurons that responded to a picture of a baseball, but not a picture of a face
- Neurons responded in the same way both when percieving and imagening the objects.
- Demostrated a possible physiological mechanism for imagery
Bihan et al. [1993]
Brain activity in perception and imagery
Demostrated that both perception and imagery activate the visual cortex.
- Activity in the striate cortex increased both when observing and imagening the stimulus
- In another experiement it was found thinking that involved imagery generated greater visual cortex response than thinkinh that involved nonimagery
Bihan et al. [1993]
Brain activity in perception and imagery
Demostrated that both perception and imagery activate the visual cortex.
- Activity in the striate cortex increased both when observing and imagening the stimulus
- In another experiement it was found thinking that involved imagery generated greater visual cortex response than thinkinh that involved nonimagery
Bihan et al. [1993]
Brain activity in perception and imagery
Demostrated that both perception and imagery activate the visual cortex.
- Activity in the striate cortex increased both when observing and imagening the stimulus
- In another experiement it was found thinking that involved imagery generated greater visual cortex response than thinkinh that involved nonimagery
Topographic Activation
kosslyn et al, 1995
- Specific locations on a visual stimulus cause activity at specific locations in the visual cortex
- looking at a small object causes activity in the back of the visual cortex
- looking at larger objects causes activity to spread towards the from of the visual cortex
[results]
- Both imagery and perception result in topographically organized brain activation.
Overlap between areas of activation
- Ganis’s eperiment show there is almost complete overlap of activation in the front of the brain, but some difference near the back of the brain
- Amedi found that when participants used visual imagery, the response of other areas associated with non visual stimuli decreased [could be to reduce interference since imagery is more fragile]
Multivoxel Pattern Analysis
- The classifier predicted the correct picture on 63% of the trials for perception
- 55% for imagery
Transcranial Magnetic Stimulation
Kosslyn et al. 1999
- After creating a visual lesion in the visual cortex
- Participants we’re slower to make decisions based on their visual imagery
- slowing effect occurred for both perception and imagery
Removing part of the visual cortex
Patient M.G.S
-Had part of her right occipital lobe removed
- before operation, she estimated that she was 15 feet away for an imaginary horse in an overflow task
-After the operation her estimation increased by 35 feet
- occurred because removed part of visual cortex reduced the size of her field of view
Unilateral Neglect
Caused by damage to the parietal lobe
- complete neglect of one half of the visual field
- Luzzati (1978) found that it included the ability to imagine in that half of their visual view
Double dissociation
- [guarlia] perception okay, imagery neglect limited to one side
- [R.M] perception okay, imagery poor complete
- [C.K] poor perception (visual agnosies), imagery okay
Method of loci
Method in which things to remember are placed at different locations in a mental image of a special layout
Verbalizer-Visualizer Dimension
[Kozhevnikov et al.]
The proposal that some people solve problems through verbal-logical methods, while others do so through imagery
Spatial imagery
The ability to image spatial relations
Object Imagery
The ability to image visual details
The Paper Folding Test [PFT]
Designed to mesure spatial imagery
- participants saw a piece of paper being folded and then pierced by a pencil
- their task is to pick from 5 choices what the paper would look like unfolded
The Vividness of Visual Imagery Questionnaire [VVIQ]
Designed to measure object imagery
- Participants rate in a 5-point scale the vividness of mental images they’re asked to create
Imagery Test Results
- Low spatial imagery - low score on the PFT, 62% had a had high scores on the VVIQ did better on degraded pictures task
- High spatial imagery - high score on the PFT, 51% had a low score on the VVIQ, did better in mental rotation task
Francis Galton
The idea that people differ in imagining [degrees of vividness]
Aphantasia
Individuals with visual imagery that is either entirely absent, or dim and vague
- often interpret visual imagery as a metaphor
- perform well on measures of visual working memory but use different strategies
- 4% of the population
Hyperphantasia
Visual imagery that is as vivid as real seeing
-Associated with an increased occurrence of synesthesia
- Greater connectivity between prefrontal and visual areas
Auditory Imagery
Priming effect exist similar to visual imagery
- overlap with perceptual system
Motor Imagery
Involves brain areas that are also involved in actual movement
- Mental rotation tasks can be solver with motor or visual imagery
- Primary motor cortex
