CH 3: sensation and perception

sensation

detection of stimuli in surroundings; activation of receptors in the 5 senses

perception

brain processes and makes sense of external stimuli (surroundings)

transduction

turning outside activity into neural activity in the brain

sensory receptors

specialized forms of neurons (stimulated by energy)

synesthesia

signals from various senses are process differently (eg: smelling a sound)

difference threshold

minimum amount of change required for a person to detect a difference between 2 stimuli

absolute threshold

minimum intensity of stimulation needed before experiencing sensation

subliminal stimuli

stimuli that are below level of conscious awareness

subliminal perception

when subliminal stimuli act upon the unconscious mind, possibly influencing behavior

habituation

brain is used to environment, not conscious of certain stimuli

sensory adaptation

sensory receptor cells become less responsive to stimulus that is unchanging (eg: hearing a startling noise)

brightness

determined by AMPLITUDE of wave; the brighter the light=higher the wave

color (hue)

determined by LENGTH of the wave; long wavelengths found at red end, short found at blue end

saturation

the PURITY of color people see

cornea

clear membrane that covers surface of the eye; protects it and focuses the light coming into the eye

aqueous humor

visual layer below cornea; clear watery fluid that’s continually replenished, supplies nourishment to eye

rods

visual sensory receptors found at back of retina; non-color sensitivity to low levels of light, black and white/night vision

cones

visual sensory receptors; responsible for color vision and sharpness of vision

blind spot

area in retina where axons of the 3 layers of retinal cells exit the eye to form the optic nerve; no receptors, insensitive to ligth

dark adaptation

recovery of the eye’s sensitivity to visual stimuli in light after exposure to bright lights

light adaptation

recovery of eye’s sensitivity to visual stimuli after exposure to darkness

trichromatic theory

3 different types of cones are sensitive to diff wavelengths

monochromatic vision

condition where person’s eyes have cones that are working incorrectly (genetic mutation)

dichromatic vision

condition where one cone doesn’t work properly where resulting colors are determined by a combo of only 2 cones

prosopagnosia

deficits in the ability to recognize faces

audition

hearing; sense of sound perception

sound wave

pattern of changes in air pressure which produces the perception of sound

wavelength

interpreted as frequency or pitch (high, med, low)

amplitude

interpreted as volume (soft, loud)

purity

interpreted as timbre (richness in a tone)

hertz

cycle/waves per second, measurement of frequency

cochlear implant

hearing aid; mic implanted behind the ear that picks up sound

sensorineural hearing loss

damage to inner ear nerves (caused by old age or loud sound)

gustation

sensation of a taste

olfaction

sense of smell

olfactory bulbs

areas of brain that receive info from the olfactory receptor cells, info is sent from bulbs to piriform cortex, orbitofrontal cortex, and amgydala

pheromones

chemical messages released by humans and animals that trigger reactions in others

somesthetic senses

soma=body, esthetic=feeling; the body senses consisting of the skin senses, the kinesthetic sense, and the vestibular senses

visceral pain

detects pain and pressure in organs

somatic pain

pain sensations in the skin, muscles, tendons, and joints

kinesthesia

awareness of body movement

proprioception

awareness of where the body and body parts are located in relation to each other and everything else

vestibular sense

awareness of balance, position, and movement of head and body through space in relation to gravity’s pull

perception

method where the sensations experienced at any moment are interp & organized in meaningful fashion

size constancy

we tend to see an object as the same size no matter how far away

shape constancy

we tend to see the shape of an object as constant

brightness constancy

tendency to perceive the brightness of an object as the same even when lighting changes

contiguity

perceive things that happen close together in time as being related

perceptual set

see things a certain way because previous experiences

top down processing

using preexisting knowledge to organize individual features into a unified whole

bottom up processing

analysis of smaller features to build up to complete perception