Perception Flashcards
What is bottom-up processing?
Where individual elements of a stimulus are analysed and then combined to form a unified perception
What is top-down processing?
Where sensory information is interpreted in light of existing knowledge, concepts, ideas and expectations
Give examples of times the brain uses mostly top-down processing?
Dreams
Hallucinations
What was the Gestalt movement interested in?
How we organise the parts of the perceptual field into a unified and meaningful whole
What did the Gestalt movement believe the goal of perception was?
To recognise objects in the environment according to the organisation of their elements
What is the Gestalt principle?
That the whole is more than and different from the sum of its parts
What are figure-ground relations?
Our tendency to organise stimuli into a central or foreground figure and a background
What is the law of similarity?
Similar elements will be perceived as belonging together
What is the law of proximity?
Elements that are near each other are likely to be perceived as part of the same configuration
What is the law of closure?
People tend to fill in gaps in incomplete figures
What is the law of continuity?
People link individual elements together to form a pattern that makes sense
What is a perceptual schema?
A mental representation or image containing the critical and distinctive features of a person, object, event, or other perceptual phenomenon
What is the purpose of perceptual schema?
They provide mental templates that allow us to identify and classify sensory input
What is a perceptual set?
A readiness to perceive stimuli in a particular way
What are perceptual constancies?
They allow us to recognise familiar stimuli under varying conditions
What are the three perceptual constancies?
Shape constancy
Lightness constancy
Size constancy
What is shape constancy?
It allows us to recognise people and other objects from many different angles
What is lightness constancy?
The relative brightness of objects remains the same under different conditions of illumination
What is size constancy?
The size of objects remains relatively constant even though images on our retina change in size with variations in distance
What is depth perception?
It requires that we perceive the distance of objects in the environment from us and from each other
What are the two depth perception cues?
Monocular cues
Binocular cues
What are monocular cues?
Depth perception cues that require only one eye
What are the different monocular cues?
Patterns of light and shadow
Linear perspective
Texture and clarity
Height in the horizontal plane
Relative size
Motion parallax
How do patterns of light and shadow act as depth perception cues?
They tell us whether things are sticking outwards or inwards
How does linear perspective act as a depth perception cue?
Parallel lines converge in the distance
How do texture and clarity act as depth perception cues?
Clear objects are judged to be closer than hazy objects
Gradients are smoother when further away, and more obvious when closer
How does height in the horizontal plane act as a depth perception cue?
Objects that are closer to the horizon are further away
How does relative size act as a depth perception cue?
With objects of a similar size, the one that looks smaller is judged to be farther away
How does motion parallax act as a depth perception cue?
If we are moving, nearby objects appear to move faster than faraway ones
What are binocular cues?
Depth perception cues that require both eyes
What are the different binocular cues?
Binocular disparity
Convergence
How does binocular disparity act as a depth perception cue?
Each eye sees a slightly different image - both are sent to feature detectors which are sensitive to this, causing the neurons to fire more quickly, allowing the brain to identify depth
How does convergence act as a depth perception cue?
This is produced by feedback from the muscles that turn your eyes inward to view a close object - the brain can tell the depth of an object based on the level of convergence on it
What is the limit of convergence?
It only works as a depth perception cue for objects at arm’s length or closer, since the eyes cannot turn outwards
