Psychology 101-Review: Sensation & Perception

sensation

detection of a physical energy by means of specialized sense organs

perception

organization and interpretation of sensory inputs

transduction

process by which a physical stimulus becomes a neural message & psychological reality

psychophysics

the study of external stimulus & the difference from the perceived experience

absolute threshold

minimum amount of intensity of stimulation required for sensation

difference threshold (just noticeable difference)

smallest difference in intensity that can be detected

sensory adaptation

the ability to ignore background noise and focus through selective attention

cornea

a curved, transparent layer covering the iris and pupil

nearsighted

if the cornea is too steep, images fall short of the retina, so distant vision is blurred

far sighted

if the cornea is too flat, images fall too far, so close up images are blurred

lens

part of the eye that is transparent, and changes shape to focus light on the back of the eye through a process called

accommodation.

iris

the colored part of the eye that is a set of muscles controlling an opening that modifies the amount of light permitted through

pupil

an opening allowing light into the eye

vitreous humor

fluid inside the eye chamber between the retina & lens

retina

a thin membrane at the back of the eye that contains receptor cells

rods

long and narrow, used in low light, and to see basic shapes and forms

cones

used in high light and give us color and detailed vision

bipolar neurons

cells of the retina that transmit signals from rods/cones to ganglion cells

ganglion cells

last cells in the retinal circuit, contain axons that leave the

eye as the optic nerve

optic nerve

axons of ganglion cells that travel to the brain, half splitting at the optic chiasm to travel to the same hemisphere and half crossing to the other side

thalamus

receives optic signals from ganglion axons of the eye and relay information to the occipital lobe of the brain

blind spot

the site where the ganglion axons converge as the optic nerve, where no photoreceptors are present, therefore no vision

fovea

the central part of the retina where sharp vision occurs

Gestalt principles of organization

help us to perceive objects in space, including: subjective contours, proximity, similarity, good continuation, closure, symmetry, and figure-ground ( the whole is more than the sum of the parts)

closure

elements tend to be grouped together if they are parts of a closed figure

continuity

oriented units or groups tend to be integrated into perceptual wholes if they are aligned with each other

proximity

elements tend to be perceived as groups if they are near each other.

similarity

elements tend to be integrated into groups if they are similar to each other

phi phenomenon

an optical illusion in which stationary objects shown in rapid succession, transcending the threshold at which they can be perceived separately, appear to move ( trailing lightbulbs)

perceptual constancy

tendency to see familiar objects as having standard shape, size, colour, or location regardless of changes in the angle of perspective, distance, or lighting.

monocular depth cues

include relative size, texture gradients, interposition, linear

perspective, height in plane, light and shadow, and motion parallax

binocular depth cues

Visual distance and depth cues that require the use of both eyes

interposition

overlapping figures tend to be perceived as one behind the other

size perspective

distant objects appear smaller in size relative to closer objects

linear perspective

convergent lines appear as leading away from a viewer

texture gradient

distant objects tend to appear fuzzy

motion parallax

close objects appear to move faster than distant ones

muller leyer illusion

an arrow with two tails is perceived as longer than an arrow with two heads.

ponzo

the difference in the gap of same size horizontal lines from the framing converging "rail road tracks" makes the horizontal lines appear to be different lengths.

ames room

room is constructed so that from the front it appears to be cubic-shaped, However, this is a trick of perspective and the true shape of the room is trapezoidal.

context

ground provides meaning to a figure

poggendorf

the brain's perception of the interaction between diagonal lines and horizontal and vertical edge.

hue

the color of light

brightness

the intensity of the light that reaches our eyes