WK 4 L1 and L2 Sensation/perception- sight Flashcards
sensation
The process of by which sense organs gather info about the environment and transmit it to the brain for initial processing.
Perception
the process by which the brain selects, organises and interprets sensations.
Neuropsychology
Explains how the brain fails to function
Electrophysiology
how electricity works in the brain
deoxygenated blood- used for activity
Transduction
process of converting stimulus Information into neural impulses
Vitreous humour
clear liquid in the middle of the eye that makes it take form
Pupil
controls the amount of light that enters the eye
Iris
two bands of muscle that controls the size of pupil
Retina
Tissue at back inside surface of eye that contains photoreceptors and associated neurons
Retina function
absorbs light, processes images, sends visual info to brain- made up of rods and cones
Cones function
day vision, colour vision, high visual acuity
Rods
Night vision, monochromatic vision, low acuity
Fovea
small area in retina that contains only cone receptors
Dark adaptation
Process in which the eyes become more sensitive to light in low illumination
Psychophysics
study of relationship between physical characteristics of stimuli and the sensory experiences that accompany them.
Thresholds
our perception of various sensory inputs can only occur when the strength of the stimulus reaches a minimal threshold level of intensity
Absolute threshold
the minimum amount of physical energy needed for an observer to notice a stimulus
Difference threshold
The lowest level of stimulation required to sense a change in stimulation
Method of limits
A series of stimuli are presented to the observer until they reach a limit or point of change in their judgement
Form perception
How the brain organises patches of colour and brightness into objects
Gestalt psychology
A theory that maintained that the task of perception was to recognise objects in the environment according to the organisation of their elements
Gestalt law
law of proximity, similarity, good continuation and closure
Law of proximity
elements that are closest together will be perceived as belonging together
Law of similarity
similar colours/hues are grouped together
Law of closure
Perception is visual binding, closing a shape that isn’t there
Depth perception
How do we interpret a flat 2D image on the back of the eye as a 3D image
cofactors of depth perception
convergence, texture cues and atmospheric haze
Convergence
eyes slowly move inward when foviating on an object
Texture cues
how texture effects perception in how far away things are
Atmospheric haze
things near to you have colour, things further away are washed out
Horizon
objects nearest to the horizon appear farthest away
Binocular disparity
slight difference in images between left and right eye
Stereopsis
taking the least distance in seconds of arc that the individual can perceive binocularly
Colour perception
Important for survival
Colour perception- wave length
the distance between adjacent waves of radiant energy. in vision most closely associated with the perceptual dimension of hue, measure in nanometers
3 physical dimensions of colour
hue, brightness and saturation
hue
different wave lengths tend to be perceived as different hues
Brightness
the amplitude of the light wave effects the perceived brightness of the colour
Saturation
The purity of the light. The more white light a colour has, the less saturated it is.
Colour mixing
The addition of two or more lights of different wave lengths
Additive colour mixing
superimposing lights. putting more light into the mixture than exists in one light by itself
Subtractive colour mixing
removing some wave lengths of light, leaving less light than was originally there.
Colour perception theories
trichromatic and opponent process theory
Trichromatic theory
experiments showed that any colour could be matched by the additive mixture of just three appropriately chosen colours
Opponent process theory
the trichromatic theory could not explain all aspects of vision.
