perception Flashcards
what is the striate cortex?
the primary visual cortex
where the most basic visual information is processed
what is the extrastriate cortex?
the region of cortex bordering the primary visual cortex and containing multiple areas involved in visual processing
what happens in the visual ventral pathway?
process visual information to work out WHAT something is
what happens in the visual dorsal pathway?
process visual information to work out WHERE things are
what is a receptive field?
particular region of sensory space in which a stimulus will modify the firing of that neurone
what is the inferotemporal cortex?
part of the cerebral cortex in the lower portion of the temporal lobe, important for object recognition
what is agnosia?
when you cannot recognise an object even though you can see it
what are grandmother cells?
cells that have very specific responses to very specific objects (e.g. fire when you see a Ferrari but not other cars)
what role does mid-level vision play in perception?
it organises objects into objects and surfaces
determines which regions of an image should be grouped together into objects
what is illusory contour?
when a contour (edge) is perceived even though nothing changes from one side of the contour to the other
what does gestalt psychology suggest?
that a scene is perceived as an organised whole rather than the constituent parts
give some examples of gestalts grouping rules
good continuation texture similarity proximity parallelism symmetry common region connectedness common fate synchrony
what are perceptual committees?
a metaphor for how perception occurs
perception can be ambiguous so ‘committees’ must work together to integrate conflicting opinion
what is an ambiguous figure?
a visual stimulus that gives rise to two or more interpretations of its identity or structure
what is an accidental view point?
a viewing position that produces some regularity in the visual image that is not present in the world (holding up the leaning tower of Pisa)
what is ‘figure-ground assignment’?
process of determining some regions of an image belong to the object and some to the background
what are the gestalt figure-ground assignment principles? (5)
surroundedness size symmetry parallelism relative motion
what is the principle of ‘surroundedness’
the surrounding region is likely to be the background o fan image
what is the gestalt figure-ground assignment principle of ‘size’?
that the smaller region is likely to be the figure
what is the gestalt figure-ground assignment principle of symmetry?
that a sy,,metrical region tends to be seen as a figure
what is the gestalt figure-ground assignment principle of parallelism?
that regions with parallel contours tend to be seen as a figure
what is the gestalt figure-ground assignment principle of relative motion?
that if one region moves in front of another, then the closer region is the figure
what is occlusion?
when one object partially covers another
what is a non accidental feature?
a feature of an object that is not dependent on the viewing position of the observer