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auditory perception
determine words, identify speaker, localize sound in space
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visual perception
- differentiate objects
- determine position motion shape, texture
- make contact with long term memory
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templatic hypothesis
- we store images of encountered objects
- we can recognize objects based on their familiarity
- (INCORRECT)
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problems with templatic hypothesis
- we can recognize things we've never seen before
- we can recognize objects from new angles
- we can recognize objects when features are missing
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segmentation
- achieved by:
- edge detection
- determining figure group
- grouping
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what is the sensory input and perceptual output of vision?
- sensory input: 2-D array of color and luminance values
- perceptual output: 3-D objects
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what is sensory input and perceptual output of audition?
- sensory input: sequence of air pressure values
- perceptual output: words
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How do we identify edges?
enhance contrast (ex. mach bands)
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lateral inhibition
adjacent neurons inhibit each other to enhance contrast
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how does the herman grid exhibit lateral inhibition?
black squares make the white pathways more white, so corners appear darker
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how do we find lines in segmentation?
- each neuron responds to a point in the visual field
- When a bank of on-center, off-surround cells are jointly firing, this indicates a line
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figure ground
determining what is object and what is environment
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gestalt principles
- heuristics for organizing visual objects
- similarity
- proximity
- good continuation
- closure
- simplicity
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binocular disparity
distance between the eyes causes the visual scene to appear slightly differently on the two retinas
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texture density gradient
- less density in same images = indicates closer proximity
- more density =distance
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how does light effect our visual perception?
location and effects of light source give us depth cues
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occulsion
we can tell about an object's relative position based on the objects in front of and behind that object
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4 cues to object location
- binocular disparity
- light source-depth cues
- occlusion
- texture density gradient
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normalization
disregarding irrelevant surface materials in order to make contact w. long term memory
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color constancy
- be able to understand that colors remain the same even in different lightings
- example of normalization
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top down processing in visual perception
we formulate a hypothesis about the identity of a stimulus, select and examine relevant aspects of the stimulus to check
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convergence
brain uses how much eyes turn to view nearby objects to determine depth perception
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ames boxes
rooms which play with linear perspective and distance clues
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ponzo illusion
when two lines begin to form a triangle and there are two lines in between those other lines, the two lines inbetween appear to be different in size
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motion after effects
if you stare at a moving image and then look at a stationary scene, the stationary scene appears to move
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bottom up processing
info from sensory receptors is combined to make more complex and recognizable patterns
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monocular vision cues (6)
- occlusion
- relative size
- familiar size
- linear perspective
- texture gradient
- position relevant to horizon
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binocular vison cues (2)
- retinal disparity
- convergence
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motion parallax
the relative movements of objects at various distances from the observer
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iris
changes shape to let in more/less light
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pupil
small opening in eye which lets in light waves
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What are the four possible outcomes in signal detection theory?
- hit
- miss
- false alarm
- correct rejection
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sensory coding
the process by which sensory organs translate the physical properties of stimuli into neural impulses
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What are on-center, off-surround cells and how do they contribute to finding lines?
- on-center off-surround cells selectively fire when light is in the center of their receptive cells.
- When a bank of on-center off-surround cells are firing together, this is indicates a line
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