Sensation and Perception

Hearing, touch, smell

Hearing

Audition: energy form is sound waves – slower range of speeds, but work similar to sound waves

Pitch: how high or low sound is

Timbre: complexity of tone (instrument variations)

Decibels: measurement of the intensity of the sound – above 130 they are painful (siren, shot gun blast, jet airplane on runway, FULL VOLUME HEADSET!)

Sleep is disturbed by noise at about 70 decibels; soothing with a continuous sound around 50 decibels

Shape of ear has a purpose – cupped design of the outer ear catches the sound waves and funnels them toward the eardrum – piece of skin stretched tightly

Sound waves hit drum – it vibrates; this causes small bone to vibrate; this bone is attached to another bone and acts like a lever, causing it to vibrate; third bone is attached to a snail shaped unit (cochlea)

Key to hearing is small hairs called cilia – 20,000 hair cells are found in cochlea – we lose them as we age – tuned to different frequencies – respond to movement on only a trillionth of an inch

Electrical impulses go through auditory nerve to the brain where it is interpreted

Cells specialize – certain cells recognize important sound patterns – mothers tuned to sounds of children; newborns soothed by sound of mother’s voice

http://www.ted.com/talks/neil_harbisson_i_listen_to_color?language=en

https://www.youtube.com/watch?v=iabuAiYZVxI

Touch

Skin contains three types of touch receptors or cutaneous – each sends message to brain

Pressure – pinpricks, bruises, bug crawling Changes in temperature Injury or poison – cause painful feelings like when we have a major

cut or burn https://www.ted.com/talks/katherine_kuchenbecker_the_technology_of_touch

Smell

Olfaction is sense of smell – most animal like of human senses – hard to define using words – but associate with emotional event and we never forget

Nasal cavity has layer of mucus imbedded with cilia – collect molecules of odor – sent to olfactory bulbs wich generate a code to send to brain

Most critical is conveying information about food heading to our mouths – smell more important than taste

Pheromones – used by animals to communicate sexual interest

https://www.youtube.com/watch?v=VuR6QuWrHrc

https://www.youtube.com/watch?v=WxQiNOiscRc

https://www.youtube.com/watch?v=WxQiNOiscRc

Taste

Taste receptors work through chemical communication

Major receivers are taste buds (little red spots, rich in blood supply)

Mucus and saliva in mouth cleanse the buds – takes a while – think brushing your teeth and drinking orange juice

Four types of receptors – sweet, salt, bitter, sour (umami?)

https://www.youtube.com/watch?v=W2xPOZPlxo4

Salt needs Necessary for survival – operates nerve cells, keeps body chemistry in

balance, used for muscle contraction

Newborns don’t like salt, after few months, we crave it; tapers off as we age and then reappears later in life

Pregnant women often crave salt for the fetus

Sugar Needs Most animals need sugar – newborns will actively seek it

Vital for energy to run body

Often put on food in restaurants to make us crave it (hamburgers at fast food chains)

Sourness and Bitterness

More than one type of bitterness detectors

Help us detect poisons – most are bitter in one way or another

Sourness is also a protective sense – spoiled food often tastes sour

https://www.ted.com/talks/jinsop_lee_design_for_all_5_senses