PERCEPTION Flashcards
bottom-up processing
individual elements of. stimulus are analysed and then combined to from a unified perception-data driven
top-down processing
sensory information is interpreted in light of existing knowledge, concepts, ideas and expectations- concept driven
Gestalt meaning
German for pattern, whole or form- the wholes we perceive are often more then the sum of their parts.
Gestalt- figure -ground relations
out tendency to organise stimuli into a central or foreground figure and a background (horizon)
Gestalt laws of perceptual organisation
- similarity
- proximity
- closure
- continuity
gestalt laws of similarity
when parts of a configuration are perceived as similar, they will be perceived as belonging together
gestalt laws of proximity
elements that are near to one another are likely to be perceived as part pf the same configuration
gestalt law of closure
people tend to close the open edges of a figure or fill in gaps in an incomplete figure , so that their identification of the form is is more complete than what is actually there
gestalt law of continuity
people link individual elements together so that they form a continuous line or pattern that makes sense
percetual schema
a mental representation or image containing the critical and distinctive features of a person, object, event of other perpetual phenomenon (top-down fashion)
Gregory’s (1996) qualia
like flags, issues about the present that indemnify stimuli and experience in the here and now and prepare us for immediate action
bayesian inference
involves conditional probability- probability that something is the case given the knowledge that something else is true (a child had chickenpox because they have lots of spots appearing on their face)
perceptual constancies
allow us to recognise familiar stimuli under varying conditions
shape constancy
allows us to recognise people and other objects from many different angles
lightness constancy
the relative lightness of objects remains the same under different conditions of illumination
size constancy
perception that the perceived size of objects remains relatively constant even thought imagine on the retina change inside with variations of distance
Monocular depth cues
Only one eye is needed:
- patterns of light and shadow
- linear perspective
- interposition
- height in the horizontal plane
- texture
- clarity
- relative size
- motion parallax
Binocular depth cues :binocular disparity
each eye sees a slightly different image
Binocular depth cues : convergence
produced by feedback from the muscles that turn your eyes inwards to view a close object
stroboscopic movement
illusory movement produced when a light is briefly flashed in darkness and the, a few milliseconds later, another light is flashed nearby. The light is perceived to move from A to B.
illusions
compelling but incorrect perceptions
feature theory of face perception
Basic info about a person is perceived from their face, facial feature expressions are then processed. Th model of the face produced is consigned to memory where personal identity is coded along with these features.
Thatcher illusion
eyes and mouth have been turned upside down even when it looks completely normal the the right way up
prosopagnosia
lose the ability to recognise faces
perception
our experience of the outside world
primary visual pathway
the left and right visual field
two streams hypothesis
processing of visual info takes place in two different visual pathways :
ventral stream: ‘what’ pathway (object)
dorsal stream: ‘where pathway (spatial) or ‘how’ pathway (guides)
Bottom up processing- Marr (1982)
Primal Sketch
- detection of gradient, edges and boundaries
- outlines and features compared to original
- 5D Sketch
- depth, motion and shading
3D Sketch
-adds object recognition
Ecological theory
claims we can receive info direct from environment without any higher order cognitive processing
change blindness
failure to notice substantial objects or scene changes
eye movements:
fixations
rests on fixed location
eye movements:
saccades
between two fixations
eye movements:
smooth pursuit
moving objects
critical periods
during which certain kinds of experiences must occur in perceptual abilities and the brain mechanisms that underlie them are to develop normally
Blakemore and Cooper
Cultural factors can …
…influence certain aspects of perception such as pictures and susceptibility to illusions, however most concepts are constant across cultures.
