chapter 4-perceiving and recognizing objects Flashcards
extrastriate cortex
region of cortex bordering the primary visual cortex; V2, V3, V4
what comes after extrastriate cortex
where and what pathways
where pathway
locations and movement of objects; motion/direction, depth sensitive
where pathway location
dorsal, parietal, MT/MST
what pathway
names and functions of objects; specialized areas that respond best to different types of objects; object recognition
what pathway location
ventral, temporal, IT
perception processing is what pathway
ventral, what
action processing is what pathway
dorsal, where
double dissociation
two related mental processes can function independently of each other; damage to one does not affect the other
ventral stream damage
no perception, visual form agnosia
dorsal stream damage
no action, optic ataxia
what imaging technique can be used to find brain areas that do more of one thing than another
fMRI
MT/medial temporal function
motion processing (dorsal)
FFA/fusiform face area
faces (ventral)
EBA/extrastriate body area
responds well to body parts that aren’t the face (ventral)
PPA/parahippocampal place area
mix location and functionality, processing scenes and places (houses)
what process helps with rapid object recognition; little feedback from higher brain areas
feed-forward process
feed-forward process
carries out a computation one neural step after another, without feedback from higher areas to lower ones
what imaging technique is used for the feed-forward process
EEG, ERP
global superiority effect
properties of the whole object take precedence over the properties of parts of the object; large scale properties, overall shape
lower vision
detection of basic features (spots and bars); retinal starting point –> LGN –> V1
middle vision
loosely defined stage of visual processing that deals with perception of edges and surfaces, determines which regions of an image should be grouped together into objects; V2, V3
upper vision
perception of objects; IT
receptive fields in extrastriate areas are more ___ than the striate cortex
sophisticated
extrastriate receptive fields respond to
visual properties important for perceiving objects; boundary ownership and illusory contours
similarity
items with similar properties tend to group
proximity
items that are near each other tend to group
texture segmentation
carving an image into regions of common texture properties
good continuation
two elements will tend to group together if they lie on the same contour
occlusion
visual system blocked, cant see all of the object
reliability
the degree to which two line segments appear to be part of the same contour
T junctions
occlusion of one object from another
arrow and Y junctions
indicate corners within an object
generic
assumed to be typical or widely representative
accidental
specific/unusual, doesnt generalize; hiding or losing info about object
dealing with occlusion; preference for ___ views
generic
nonaccidental feature
feature of an object that is not dependent on the exact (accidental) viewpoint
recognition by components model
biederman’s model of object recognition, objects are recognized by the identities and relationships of their component parts
geons
geometric ions out of which objects are made
recognition by components model is viewpoint ___
invariant
viewpoint invariant
recognize object no matter what angle
the father an object is rotated from a learned view, the ___ it takes to recognize
longer; visual system not necessarily viewpoint invariant
prosopagnosia
inability to recognize faces; right hemisphere damage (FFA)
