Chapter 9: Mental Imagery Flashcards
what is mental imagery?
the ability to perceive something without a stimulus
-the feel of a dogs fur (tactile imagery)
-the smells of coffee (olfactory imagery)
-the sound of an airhorn (auditory imagery)
visual imagery
seeing in the absence of a visual stimuli
tactile imagery
Paul Bach y Rita
-clever engineering
electrical stimuli to the tongue used to match visual image from camera
(144 - 625 tongue pixels)
from this the participant is able to form imagery from this information
Laeng 2014
had participants look at an empty gray background
-participants imagined scenarios of different brightness
-measured pupil diameter with eye tracking camera
imagine a sunny sky-pupils open
imagine a dark sky-pupils close
kuzendorf (1981) & Kojo (1985)
had participants imagine their hand was heating up or cooling (“imagine it is in a stream”)
using the mental imagery vividness questionnaire and hand temperature
hand temperature changed (1-3 degrees) proportionate to their ability to imagine the stimuli
yarmey 1965
participants asked to remember a series of word pairs
-abstract words like “truth & spirit” had only 15 pairs recalled
-concrete words like “rodent & hat” had 22 pairs recalled
we don’t have schemas for things like
truth” so they’re hard to visualize
the conceptual peg hypothesis
what is the conceptual peg hypothesis?
concrete nouns give us physical images we can “hang” other pieces of information on
ex. Christmas tree-peg
-star ornament
-red presents
kosslyn 1978
mental images sometimes seem to have physical properties
participants memorized a map and then answered questions about the island from memory and draw it from memory
the response was linear to the measured distance on the map
questions about near locations had a shorter response time
questions about distant locations had longer response times
participants were using mental walking (visiospatial sketchpad)
Ganis 2004
used fmri to view peoples brains during visual stimuli vs. visual imagination
the frontal and temporal are involved in high level image processing, and they looked almost identical on the scans
Kreiman 2000
probed an intracranial electrode of temporal neurons during imagination
-activation between imagination and visual stimuli was very similar
-r^2 had a 95% correlation
imagery activation pattern of 15 neurons was 95% similar to perceptual stimuli
-slope of the line was .85
imagery activation was 85% as strong as perception
farah 2000 task
patient MGS
was asked to imagine a horse and do a mental walk toward it
(said horse was about 15 feet away)
right occupital lobe was removed to prevent seizures, was asked to complete the same mental walk
(said horse was farther)
why-
the occipital lobe is like a canvas. smaller canvas=farther away
mental imagery results in a unique pattern of neural activation for example, you will have different firing patters for x than y
x-imagining a parade
y-imagining a marathon
computers learn to recognize specific imagery activation patterns using…
multivoxel pattern analysis (MVPA)
what is MVPA procedure?
- participants look at 100 different picture of apples while the mri maps brain activity each time
- a computer finds an average apple activation pattern
- computer looks for this pattern in the future to “predict apple thoughts”
Johnson 2024
participants shown 4 different nature scenes
MVPA procedure applied
the computer was then tasked with guessing which of the two scenes the participant was looking at or thinking of-50/50 chance
when the participant was looking at 1/2 scenes-computer correct 63% of the time
when the participant was imagining 1/2 scenes-computer correct 55% of the time
its a start?
