Sensation & Perception Flashcards
(77 cards)
Absolute threshold
minimum of stimulus energy needed to activate a sensory system (how powerful a stimulus must be for perception)
-AKA Limen (subliminal perception refers to perception of stimuli below a threshold)
Difference threshold
how different two stimuli must be before they are perceived to be different
JND- just noticeable difference
- same as difference threshold, but different units
- if diff threshold is 2 inches, then it is 1 JND
Weber’s law
change in stimulus intensity needed to produce a JND0 divided by stimulus intensity of the standard stimulus is a constant
Fechner’s law
relationship between intensity of sensation and intensity of the stimulus
Signal detection theory
nonsensory factors influence what the subject says she senses (experiences, motives, expectations..)
(response bias)- tendency to respond due to nonsensory factors
Reception
- 1st step in sensory info processing
- each sensory system has receptors that react to physical energy
Transduction
- 2nd step
- translation of physical energy into neural impulses or action potentials
projection areas
brain areas that further analyze sensory input
cornea
clear, dome like window in the front of eyes
-gathers and focuses incoming light
pupil
- hole in the iris
- contracts in bright light
- expands in dim light to let more light in
Iris
- colored part of eye
- controls pupil size and the amount of light entering eye
Lens
- lies behind the iris
- controls curvature of light coming n and focuses near or distant objects on the retina
duplexity / duplicity theory of vision
- the retina contains two kinds of photoreceptors
- light passes through intermediate sensory neurons before reaching photoreceptors
- blind spot where the optic nerve leaves the eye
Cones
- color vision
- fine detail
- bright light
Rods
- reduced illumination
- low sensitivity to detail and not involved with color
Fovea
- middle section of retina with only cones
- most sensitive in daylight
- best visual acuity
Feature detection theory
-certain cells in the cortex are maximally sensitive to certain features of stimuli
-3 types of cells are
simple
complex
hypercomplex
Simple
Complex
Hypercomplex cell functions
simple- orientation
complex- movement
hypercomplex- shape
Brightness vs illumination
brightness- subjective impression of intensity of a light stimulus
illumination- physical, objective measurement of light
Dark adaptation
caused by regeneration of rhodopsin, the photopigment in rods
Lateral inhibition
adjacent retinal cells inhibit one another; sharpens and highlights borders between light and dark areas
Color perception
wavelength of light entering eye
subtractive color mixture
- when you mix pigments
- blue and yellow make green