Week 10 Flashcards
perceptual failures
cases in which our perceptual experience of a stimulus differs form the actual characteristics of that stimulus
three approaches to perception
computational model
constructivist approach
ecological approach
computational model
focuses on how computations by the nervous system translate raw sensory stimulation into an experience of reality
Owes much to the other two theories that came earlier
constructivist approach
taken by those who argue that the perceptual system uses fragments of sensory information to construct an image of reality
same stimulus creates different perceptions in different people
Our perception is strongly influenced by what we have learned from our experiences and by the expectations and inferences that those experiences create
ecological approach
an approach to perception maintaining that humans and other species are so well adapted to their natural environment that many aspects of the world are perceived without requiring higher-level analysis and inferences
Gibson
Primary goal of perception is to support actions by ‘tuning in’ to the part of the environment that is most important for performing those actions
Less interested in our inferences
perceptual organisation
task of determining what edges and other stimuli go together to form an object
creates subjective contours
figure ground discrimination
ability to organise a visual scene so that it contains meaningful figures set against a less relevant ground
reversibility figures
you can repeatedly reverse your perceptual organisation of what is figure and what is ground
Gestalt grouping principles
proximity similarity continuity closure closure texture simplicity common fate
common fate
when objects are moving in the same direction at the same speed, we tend to perceive them as being together
Palmer’s three additional grouping principles
synchrony
common region
connectedness
visual dominance
if conflicting impressions, believe our eyes rather than ears
depth perception
the ability to perceive distance
depth perception elements
interposition or occlusion relative size height in visual field linear perspective reduced clarity light and shadow gradient of texture
interposition or occlusion
closer objects block the view of things farther away
relative size
if two objects are assumed to be about the same size, the object producing a larger image on the retina is perceived to be closer than the one producing a smaller image
height in the visual field
On the ground, more distant objects are usually higher in the visual field than those nearby
linear perspective
objects closer to the point at which two lines appear to converge are perceived as being at a greater distance
reduced clarity
increased distance usually produces less clarity and a blue hue
light and shadow
perception of 3D
gradient of texture
graduated change in the texture, or grain, of the visual field whereby objects with finer, less detailed textures are perceived as more distant
motion parallax
Difference in the apparent rate of movement of different objects provides information about the relative distance of those objects
Muscles surrounding the lens either tights, to make the lens more curved for focusing on close objects, or relax to flatten the lens for focusing on distant objects
Information relayed to the brain, providing an ocular accomodation that helps create the perception of an object’s distance
eye convergence
rotation of the eyes inwards to project the image of an object on each retina
closer the object, more the eyes must converge
