Problem 4: Object perception Flashcards
visual agnosia
problems with object recognition and object constancy even though stimuli is registered in the brain
apperceptive agnosia
object recognition problems
integrative agnosia
difficulties perceiving different parts as a whole
integrative agnosia
difficulties perceiving different parts as a whole
associative agnosia
difficulties in understanding the meaning of an object
Treisman & Gelade (1980), which types of attention, types of visual search
Feature integration theory: explains how we combine different pieces of visual information to make a complete perception of the object
- reflexive attention: driven by stimuli
- voluntary attention: voluntarily focussing on something
- feature (pop-out) search: target possesses one distinguishable feature
- conjunction search: searching for combination of multiple features
what are the stages in the Feature integration theory
-preattentive stage: focus on aspect of the objects (feature search)
-focussed attention stage: multiple aspects are combined (conjunction search)
recognition by components theory + principle of componential recovery
recognition of objects is based on geons (basic geometrical features of an object). the principle of componential recovery = we can identify an object if we can identify its geons.
what are characteristics of geons + criticism
-invariant information (can be viewed from different angles)
-discriminability (each type of object has a certain type of neon)
- resistance to visual noise
criticism:
-do not distinguish objects within a category
- cannot account for gestalt grouping and organisation theory
propagnosia
-visual impairment in recognising faces
-mostly caused by damage to the inferior part of the temporal lobe (FFA)
alexia
-acquired difficulty in reading
-can see words and letters but has no access to the orthographic networks
-caused by brain injuries
which deficits are combined most often
holistic processing (whole, relations) = faces + objects
analytic processing (parts) = objects and words
gestalt approach
approach: whole differs form the sum of its parts, rejecting structuralism: gestalt can explain apparent movement and illusory contours, structuralism can’t.
law of pragnanz
the brain tries to see the simplest patterns
law of similarity
similar things appear to be grouped together
law of common fate
things that are moving in the same direction appear to be grouped
law of familiarity
things that form familiar or meaningful patterns appear to be grouped together
principle of common region
elements that are within the same region appear to be grouped together
principle of uniform connectedness
a connected region of visual properties appears as a single unit
principle of synchrony
visual events that occur at the same time are perceived as belong together
law of closure
elements enclosing an area appear to be grouped together
figure-ground segregation + characteristics
you either focus on the object or the background
- border ownership: a visual border between figure and ground appear to belong to the figure
- figures are more memorable, symmetrical, being in the front, smaller etc.
