Sensation

sensation: your window to the world.
perception: interpreting what comes in your window.

sensation: process by which sensory receptors and nervous system receive stimulus from the environment.

bottom-up vs. top-down processing:
bottom-up: begins with sense receptors and works to the brain integration of the sensory information. (thalamus responses)
top-down: into processing guided by higher level mental process.

absolute threshold: minimum stimulation to detect a stimulus 50% of the time.

difference threshold: minimum difference that a person can detect between 2 stimuli. known as just noticeable difference.

weber's law: idea that to perceive a difference between two stimuli, they must differ by a constant percentage; not a constant amount.

signal detection theory: predicts how we detect a stimuli amid other stimuli. assumes that we do not have absolute threshold, we detect stuff based on experience and motivation.

sensory adaption: decreased responsiveness to stimuli due to constant stimulation.

selective attention: focusing of conscious awareness on a particular stimuli.

cocktail party phenomenon: describes ability to focus one's listening attention on a single talker among a mixture of conversations and background noise, ignoring other conversations. form of selective attention.

vision: most dominating sense. visual capture.
phase 1: gathering light
short waves = higher frequency (bluish color, higher pitched sounds)
long waves = low frequency (reddish wave, low-pitched sounds)
height of wave gives it's intensity (brightness)
length of waves gives it's hue (color)
ROY G BIV
long waves = more red
short waves = more violet

transduction: transforming signals into neural impulses. information goes from senses to thalamus, then various areas in brain.
conversion of one form of energy to another.
stimulus energies to neural impulses.
ex. light energy to vision
chemical to taste and smell. sound waves to sound.

color vision 2 major theory:
young-helmholtz trichromatic (3 color) theory: 3 types of cones.

• red
• blue
• green

these types of cones can make millions of combinations of colors. most color blind people simpy lack cone receptors for one or more of these primary colors.

opponent-process theory: the sensory receptors come in pairs

• red/green
• yellow/blue
• black/white

if one color is stimulated, the other is inhibited.

hearing: we hear sound waves
height of waves gives us amplitude of the sound.
frequency of waves gives the pitch of sound.

transduction in ear: sounds waves hit ear drum then anvil. then hammer. then stirrup then oral window. everything is vibrating. then cochlea vibrates which lined with mucus called basilar membrane and has hair cells.
when hair cells vibrate they turn vibrations into neural impulses which are called organ of corti. sent to the thalamus.

place theory: different hairs vibrate in the cochlea when there are different pitches.
so some hairs vibrate when they hear high pitches and others when they hear low pitches.

frequency theory: all hair vibrate, but at different speeds.

deafness:
conduction deafness: something goes wrong with sound and vibration or the way to cochlea. you can place the bones or get a hearing aid.

nerves (sensorineural) deafness: hair cells in cochlea get damage. loud noises can cause this type of deafness. no way to replace the hair. cochlea implants is possible.

smell and taste:
sensory interaction: principle that one sense may induce another.

taste: we have bumps on our tongue called papillae. taste buds are located on papillae (they are actually all over mouth)
sweet, salty, sour, bitter, hot&spicy

umami: flavorful, meaty, savory taste.

touch: receptors located in our skin. gate control theory of pain.
gate control theory of pain: spinal cord contains neurological gate that blocks pain signals or allows them to pass on to the brain.

vestibular sense: tells us where our body oriented in space. our sense of balance.

kinesthetic sense: tells us where our body parts are. receptors are located in muscles and joints.