definitions for chpater 6 psych
Terms
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- sensation
- teh detection of teh elementary properties of a stimulus
- perception
- teh detection of the more complex properties of a stimulus including its location and nature; involves learning
- transduction
- the conversion of physical stimuli into changes in the actibity of receptor cells of sensory organs
- receptor cell
- a neuron that directly responds to a physical stimulus such as light, vibrations, ot aromatic molecules
- ANATOMICAL CODING
- A means by which the nervous system represents information different features are coded by teh activity of different neurons
- temporal coding
- a means by which the nervous system represents information different features are coded by the pattern of activity of neurons
- psychophysics
- a branch of psych that measures the quantitive relation between physical stimuli and perceptual experience
- just noticeable difference (jnd)
- the smallest diffrent two similar stimuli that can be distinguished aksi called difference threshhold
- weber's fraction
- the ratio between a just noticeable diffrence an the magnitude of a stimulus reasonably constant over the middle range of most stimulus intensities
- threshold
- the point at which a stimulus or a change in teh value of a stimulus can just be detected
- signal detection theory
- a mathematical theory o fthe detection of stimuli which involves discriminating a signal from the noice in which it is embedded and which takes into account suvject's willingness to report detecting teh signal
- receiver operating chracteristic curve(roc curve)
- a graph of hits and false alarms of subjects under different motivational conditions: indicates people's ability to detect a particular stimulus
- wavelength
- the distance between adjacent waves of radiant energy in vision most closely associated with the perceptual dimension of hue
- cornea
- the transperant tissue covering the front of teh eye
- sclera
- the tough outer layer of the eye; teh "white" of teh eye
- iris
- the pigmented muscle of teh eye that controls the size of the pupil
- lens
- the transparent organ situated behind the iris of the eye; helps focus an image on teh retina
- accomodation
- changes in teh thickness of teh lens of teh eye that focus images of near or distant objects on teh retina
- retina
- the tissue at the back inside surface of the eye that contains the photoreceptors and associated neurons.
- photoreceptor
- a receptive cell for vision in the retina (a cone or rod)
- optic disc
- a circular structure located at teh exit point form teh retina of teh axons of teh ganglion cells that form the optic nerve
- bipolar cell
- a neuron in teh retina that receives information from photoreceptors and passes it on to the ganglion cells; from which axons proceed through optic nerves to teh brain
- ganglion cells
- a neuron in teh retina that recives informaiton from photoreceptors bu means of biopolar cells and from which axons procees through teh optic nerves to teh brain.
- rod
- a photoreceptor that is very sensitive to light but cannotdetect changes in hue
- cone
- a photoreceptor that is responsible for acute daytime vision for colour perception
- fovea
- a small pit near the centre of the retina containg densely packed cones; responsible for the most acute and detailed vision
- photopigment
- a conplex molecule found in photoreceptors; when struck by light it splits apart and stimulates teh membrance of the photoreceptor in wihc it resides
- rhodopsin
- the photopigment contained by rods
- dark adaptation
- teh process wby which teh eye becomes capable of distinguishing dimly illuminated objects after going from a bright area to a dark one.
- conjugate movement
- teh cooperative movement of teh eyes, which ensures that the image of an bject falls on identical portions of both retinas
- saccadic movement
- the rapid movement of teh eyes that is used in scanning a visual scene as opposed to teh smoooth pursuit movements used to follow a moving object
- pursuit movement
- the movement that the eyes make to maintain an image of a moving imgae upon the fovea
- hue
- a perceptual dimension of colour most closely related to the wavelength of a pure light
- brightness
- a perceptual dimension of colour most closely related to the intensity or degree f radiant energy emitted by a visual stimulus
- saturation
- a perceptual dimension of colour, most closely associated with purity of a colour
- colour mixing
- the perception of two or more lights of different wavelengths seem togther as light of an intermediate wavelength
- trichromatic theory
- the colour vision is accomplished by three types of photoreceptors. each of which is maximally sensitive to a different wavelength of light
- opponent process
- the representation of colours by the rate of firing of two types of neurons: red/green and yellow/blue
- negative after image
- the image seen after a portion of teh retina is exposed to an intense visual stimulus; a negative afterimage consists of colours complementary to those of the physical stimulus
- protanopia
- form of hereditary anomalous colour vision; caused by detective "red" cones in teh retina
- deuteranopia
- form of hereditary anomalous colour vision; caused by defective "green" cone sin teh retina
- tritanopia
- form of hereditary anomalous colour vision caused by lack of "blue" cones in the retina
- hertz
- primary measure of teh frequency of vibration of the sound waves; cycles per second
- ossicle
- 1/3 bones of teh middle ear (teh hammer, anvil, and stirrup) that transmit acoustical vibrations from teh eardrum to the membrance behind the oval window of the cochlea
- cochlea
- a snail-shaped chamber set in bone in teh inner ear where auditon takes place
- oval windown
- an opening in teh bone surroudning the cochlea. teh stirrup presses against a membrance ehind the oval window and transmits sounds vibrations into the fluid within the cochlea