sensation vs perception
sensation= neurophysiology with receptors to the brain, whereas perceptioon= interpretation and the use of higher cognitive function
the point at which you detect something= absolute threshold. you must detect it 50% of the time.
above 50% detection
below 50% detection
how much do i have to change so that it is detected? "jnd"=just noticebale difference
-stimulus change, TONE DEMO.
-also follows 50% detection rule
receptors adapt to constant stimulation and then stop firing.
-your ofactory system stops firing once it has smelt the same smell for a while.
-species differences: dogs need their smell more, so it will take longer for this to happen
the skin senses
pressure, pain, warmth, cold... generality not specificity
proprioception, where are your body parts oriented? you will know this even if arm is extended behind you and you cant see it. receptors are located in muscles tendons and joints internally.
balance, semicircular canals and vestibular sacs... filled with fluid and hair cells tocuhing the fluid. every time fluid moves the hair cells move. overstimulation= dizziness
smell. your olfactory epithelium is lined with receptors. birds and humans have low levels whereas dogs have high levels
human odor sensitivity
japanese companies realized we can be effected by smell, so they started having scent breaks.
-lavender=21% decrease in error
-jasmine=33% decrease in error
-lemon=54% decrease in error but worked slower
tongue map DOES NOT EXIST. 5 basic tastes= bitter, sour, salty, sweet, umami
receptor cell location
fungiform papilla=giant bumps that you see. hundreds of buds are located on each fungiform, and there are twenty receptor cells on each bud. specificity is here on receptors!
more to taste than taste receptors
pressure, cultural differences, vision
sound=pressure variation in medium, and has three characteristics. frequency, amplitude, and complexity
pitch, herz, human range is 20-20,000 hz.
sounds below 20hz
sounds above 20000 hz
intensity or loudness, measured in decibals. at 90 dB there is some amount of damage to hearing
hair cell damage in cochlea
cochlea= snail like structure where receptors are. once hair cells have been lost, you cant get them back. your 20000 hz receptors are damged first, there is no pain and you dont feel it.
visual and taste impairment
70 db=no visual change
107 db= visual impairment.
on avg we listen at 105
taste quality is down w loud music
harmonic content or timbre. helps to distinguish instruments and voices
where humans can see
between IR and UV light
any wavelength, can detect objects but not color
color vision, by responding selectively to different wavelenghts. high intensities of light
1. hits back of eye
2. rods cones fire onto
3. bipolar fire onto
3. ganglion and their oxons form optic nerve and goes to occipital cortex in brain
area densely packed wtih cones
covered up by lateral, saccadic movements
rods adjusting to low levels of illumination
rids adjusting to high levels of illumination
dark and light adaption
rods fire to a limited range of light intensities at any given time. when they have to adapt they momentarily shut down and change
hgihly dependent on parental care , develop some sustems prenatally and some postnatally
less dependent on parental care and therefore develop all sensory systems prenatally
on prenatal day 6.5
tacticle system developed
order of systems that get developed
tactile (6.5), vestibular(8), auditory(12), visual (19)