Exam 3

Psychology 305 with Roger Knight at University of Wisconsin - Whitewater

About this deck

By: Holly Petrauskas
Textbook:

Sensation and Perception
Created: 2011-04-05
Size: 57 flashcards
Views: 48

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reflectance curve (spectral)

a plot showing the percentage of light reflected from an object versus wavelengh

photopigments

determines activity of the 3 cone types, different wavelength

metamer

two lights that have different wavelength distribution but are perceptually identical

color matching

a procedure in which observers are asked to match the color in one field by mixing two or more lights in another field.

monochromacy

a person who is completely color blind and therefore sees everything as black white, or shades of gray. can match any wavelength in the spectrum by adjusting the intensity of any other wavelength. usually only have one type of functioning receptors, usually rods

dichromacy

a person who has a form of color deficiency. can match any wavelength in the spectrum by mixing two other wavelengths. deuteranopes, protanopes, and tritanopes are all dichromats.

neutral point

the wavelength at which a dichromat perceives gray

trichromacy

a person with normal color vision. trichromats can match any wavelength in the spectrum by mixing three other wavelengths in various proportions

anomalous trichromacy

a person who needs to mix a minimum of three wavelengths to match any other wavelength in the spectrum but mixes these wavelengths in different proportions from a trichromat.

rod monochromat

a person who has a retina in which the only functioning receptors are rods.

principle of univariance

absorption of a photon by a visual pigment molecule causes the same effect no matter what the wavelength

theory of trichromacy

a theory proposing that our perception of color is determined by the ratio of activity in three receptor mechanisms with different spectral sensitivities

opponent-process theory

proposed by hering, claimed our perception of color is determined by the activity of two opponent mechanisms: a blue-yellow mechanism and a red-green mechanism. the responses to the two colors in each mechanism oppose each other, one being an excitatory response. includes a black-white mechanism, concerned with the perception of brightness

opponent neurons

neuron that has an excitatory response to wavelengths in one part of the spectrum and an inhibitory response to wavelengths in the other part of the spectrum.

opponent colors

red/green ----- blue/yellow. cannot imagine a mixture because they are paired opposite ends of spectrum,

color contrast

the difference in light intensity between two areas.

color constancy

the effect in which the perception of an objects hue remains constant even when the wavelength distribution of the illumination is changed. approximate color constancy means that our perception of hue usually changes a little when the illumination changes, though not as much as we might expect from the change in the wavelengths of light reaching the eye.

lightness constancy

the constancy of our perception of an objects lightness under different intensities of illumination

gelb effect

a black surface looks white when seen by itself but looks black when paired with a different surface. (failure of color constancy)

ratio principle

a principle stating that two areas that reflect different amounts of light will look the same if the ratios of their intensities to the of their surroundings are the same.

chromatic adaptation

prolonged exposure to light in a specific part of the visible spectrum, which adapts receptors that fire to these wavelengths by selectively bleaching a specific visual pigment. one of the mechanisms responsible for color constancy.

oculomotor cues

depth cue that depends on our ability to sense the position of our eyes and the tension in our eye muscles. accomodation and convergence are both cues

convergence

the perception that parallel lines in the distance converge as distance increases

accomodation

depth cue based on muscular sensations that occur when the eye accommodates to bring objects at different distances into focus. provides information about the distances of nearby objects

monocular cues

depth cue such as overlap relative size relative height, familiar size, linear perspective, movement parallax and accommodation, that works when we use only one eye

pictorial cues

depth cue such as overlap, relative height, and relative size, that can be depicted in pictures

occlusion

depth cue in which one object hides or partially hides another object from view, causing the hidden object to be perceived as being farther away

relative height

a depth cue. objects that have bases below the horizon appear to be farther away when they are higher in the field of view. objects that have bases above the horizon appear to be farther away when they are lower in the field of view.

cast shadows

the ratio principle does not account for effect to shadows in 3D situations, illumination cues infer the presence of surface changes, requires both local and global processing of visual scene to correctly see lightness provie info regarding the locations of objects.

relative size

when two objects are of equal size, the one that is farther away will take up less of the field of view

familiar size

our knowledge of an objects actual size sometimes influences our perception of an objects distance

atmospheric perspective

objects that are farther away look more blurred and bluer than objects that are closer because we must look through more air and particles to see them.

linear perspective

the visual pattern formed by a regularly textured surface that extends away from the observer. this pattern provide information for distance because the elements in a texture gradient appear smaller as distance from the observer increases

texture gradients

source of depth info, elements that are qually spaced a in a scene appear to be more closely packed as distance increase, more distant objects appear smaller (relative size) rocky ground

motion cues

movemetn parallax and deletion and accretion-->occurs when a farther object is covered by a nearer object due to sideways movement(occlusion in motion)

accretion--occurs when the observer moves in the other direction so the farther object is covered, make it so overlapping surfaces appear to move relative to on another, effective for detecting depth at an edge

motion parallax

occurs when we move nearby objects off to the side of our direction of movement appear to glide rapidly past us, but more distant objects appear to move more slowly (driving in a car)

stereopsis

the impression of depth that results from binocular disparity-- the difference in the position of images of the same object on the retinas of the two eyes.

retinal disparity

depth cue formed by image falling on non corresponding retinal points, Horopters

horopter

an imaginary surface that passes through the point of fixation. images caused by a visual stimulus on this surface fall on corresponding points on the two retinas.

corresponding retinal points

the points on each retina that would overlap if one retina were slid on top of the other

crossed and uncrossed disparity

crossed-objects in front of the horopter towards the person

uncrossed- objects in back of the horopter away from the person

emmert's law

a law stating that the size of an afterimage depends on the distance of the surface against which the afterimage is viewed. the farther away the surface, the larger the afterimage appears.

size distance scaling

a hypothesized mechanism that helps maintain size constancy by taking an objects perceived distance into account. S(objects perceived size)R(size of the retinal image)D(objects perceived distance)-- S= RxD

misapplied size constancy scaling

a principle proposed by richard gregory that when mechanism that help maintain size constancy in the 3D world are applied to 2D pictures an illusion of size sometimes results

size constancy

occurs when the size of an object is perceived to remain the same even when it is viewed from distances

size illusions

shadowing and visual angel are adjusted. violates S=RxD

aperture problem

a situation in which only a portion of a moving stimulus can be seen, as when the stimulus is viewed through a narrow aperture. this results in misleading information about the direction in which the stimulus is moving.

apparent movement

an illusion of movement that occurs between two objects separated in space when the objects are flashed rapidly on and off, one after another separated by a brief time interval

biological motion

motion produced by biological organisms. most of the experiments on biological motion have used walking humans with lights attached to their joints and limbs as stimuli

waterfall illusion

an aftereffect of movement that occurs after viewing a stimulus moving in one direction, such as a waterfall. viewing the waterfall creates other objects to appear to move in the opposite direction.

anomalous motion

stationary stimuli appear to move without prior adaptation to moving stimuli (weird hypnotic posters)

corollary discharge theory

according to this theory of motion perception a corollary discharge signal, which is a copy of the signal sent from the motor area to initiate an eye movement, is sent to a structure called the comparotor.

motion after effect

WAterfall illustion, see motion of stationary target after adaptation to a texture moving in a single direction, may be related to adaptation of motion sensitive neurons in area MT, shows intraocular transfer

ecological approach to perception

this approach focuses on studying perception as it occurs in natural settings, particularly emphasizing the role of observer movement.

optic flow

the flow of stimuli in the environment that occurs when an observer moves relative to the environment. forward movement causes an expanding optic flow, whereas backward movement causes a contracting optic flow.

texture gradient

the visual pattern formed by a regularly textured surface that extends away from the observer. this pattern provides information for distance because the elements in a texture gradient appear smaller as distance from the observer increases.

affordances

the information specified by a stimulus pattern that indicates how the stimulus can be used. An example of an affordance would be seeing a chair as something to sit on or a flight of stairs as something to climb.

About this deck

By: Holly Petrauskas
Textbook:

Sensation and Perception
Created: 2011-04-05
Size: 57 flashcards
Views: 48

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy