Chapter 10: Visual imagery Flashcards
Visual imagery
seeing in the absence of a visual stimulus
Mental imagery
the ability to recreate the sensory world in the absence of physical stimuli
Imageless thought debate
whether thought is impossible or possible without an image
3 basic elements of consciousness (Wundt)
images, sensations, and emotions
Conceptual peg hypothesis (Paivio)
concrete nouns create images that other words or stimuli can hang onto (e.g. boat-hat)
Mental chronometry
measuring the amount of time needed to carry out various cognitive tasks
Mental scanning
participants create mental images then scan them in their minds
Findings from Kosslyn’s mental scanning experiments
it took longer for participants to scan between greater distances in the mental images they created, indicating that imagery is spatial like perception
Imagery debate
whether imagery is based on spatial mechanisms or mechanisms related to language called propositional mechanisms
Spatial representations
different parts of an image correspond to specific locations in space
Epiphenomenon argument (Pylyshyn)
the spatial experience of mental images accompanies the real mechanism, but is not actually part of the mechanism
Propositional representations
relationships are represented by abstract symbols like an equation or a statement (e.g. the cat is under the table); imagery operates in a similar way to semantic networks
How is imagery affected by the size of an object in one’s visual field?
level of detail perceived increases as distance of an object decreases and it fills up more of the visual field
Mental walk task (Kosslyn)
participants were asked to imagine that they were walking toward their mental image of an animal and estimate their distance from it when the image began to overflow their visual field
Findings of mental walk task
participants had to move closer for small animals than for larger animals
Findings on the interaction between imagery and perception
imagery can be implicitly biased by perception (Perky) and they can facilitate one another (Farah)
Imagery neurons
neurons in the medial temporal lobe that respond to both perception and imagery of specific objects, but not to other objects
Topographic map
specific locations on a visual stimulus cause activity at specific locations in the visual cortex
Areas of the visual cortex activated by small and large objects
small objects activate the posterior or back of the visual cortex while larger objects activate the front or the anterior of the visual cortex
Areas of the brain activated by perception and imagery
both activate the same areas in the frontal lobe but perception activates more of the visual cortex in the occipital lobe
Findings on patient MGS
when part of her right occipital lobe was removed, the size of her visual field decreased, so it overflowed at a further distance (mental walk task) than prior to the removal
Unilateral neglect
ignoring objects in half of the visual field for both perception and imagery due to damage in the parietal lobes
Dissociation between imagery and perception
cases wherein perception is poor but imagery is intact, or vice versa
Patient RM
was able to draw objects in front of him (perception) but was unable to draw objects from memory (imagery) due to damage in occipital and parietal lobes
Patient CK
was able to draw objects from memory (imagery) but was unable to name objects in front of him and objects in his drawing later on
Differences between perception and imagery
perception involves bottom-up processing, is stable, and is located at both lower and higher visual centers; imagery involves top-down processing, is fragile, located at higher visual centers, and can be difficult to manipulate
Method of loci (Simonides)
things to be remembered are placed at different locations in a mental image of a spatial layout that is familiar
Eidetic imagery
photographic memory; the ability to maintain a seemingly clear mental image of an earlier perceptual event; higher incidence in children than adults and has no reliable demonstration
Pegword technique
forming associations between things to be remembered and concrete nouns that are easy to visualize
Object imagery
the ability to imagine visual details, features, or objects
Paper folding test
to measure spatial imagery, participants have to decide what a folded paper with a hole pierced on it looks like when it is unfolded
Vividness of visual imagery questionnaire
to measure object imagery, participants rated the vividness of mental images they were asked to create
Degraded pictures task
participants identify an object formed by a number of degraded line drawings; object imagers performed better
Mental rotation task
participants judge whether images are two views of the same object or mirror-image objects; spatial imagers performed better
