Sensation

Your Window to the world and the process by which one sensory receptors and nervous system receive stimulus from the environment

Bottom-Up Processing:

 begins with sense receptors and works up to the brain's integration of sensory information (thalamus)

Top-Down Processing:

 information processing guided by higher level mental processes

Thresholds

-Absolute Threshold

the minimum stimulation needed to detect a stimulus 50% of the time

-Difference Threshold

the minimum difference a person can detect between two stimuli

Weber's Law

-the 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 stimulus and other stimuli

Sensory Adaptation

-decreased responsiveness to stimuli due to constant stimulation

Selective Attention

-the focusing of conscious awareness on a particular stimulus

CocktailParty Phenomenon

-the ability to focus one's listening attention on a single talker among a micture of conversations and background noises, ignoring other conversations

VISION

the most  dominating sense

Visual Capture:

PHASE ONE: gathering light

short wavelength = high frequency (bluish colors, high pitched sounds); long wavelength = low frequency (reddish colors, low pitched sounds)

height of a wave gives us its intensity (brightness)

length of a wave gives its hue (color)

the longer the wavelength, the redder; and the shorter the more violet

PHASE TWO: Getting the light in the eye

Cornea --> Pupil --> Lens --> Retina

Color Vision

The Young-Helmholtz Trichromatic Theory (Three Color Theory)

three types of cones: red, blue, green

these three types of cones can make millions of combinations of colors

Opponent-Process Theory

the sensory receptors come in pairs; if one color is stimulated, the other is inhibited

Red/Green

Yellow/Blue

Black/White

HEARING

 

we hear sound waves and the height of the wave gives us the amplitude of the sound, the frequency gives the pitch

Transduction in the Ear

-Sound waves hit the eardrum, then anvil, then hammer, then stirrup, then oval window

-everything is just vibrating

-then the cochlea vibrates

-the cochlea is lined with mucus called basilar membrane (contains hypersensitive hairs)

-when hair cells vibrate, they turn vibrations into neural impulses which are called organ of Corti

-then sent to thalamus up the auditory nerve

Place Theory:

 different hairs vibrate in the cochlea when there are different pitches

some hairs vibrate when they hear high pitches and others vibrate when they hear low pitches

Frequency Theory:

 all the hairs vibrate but at different speeds

Conduction Deafness:

 something goes wrong with the sound and the vibrations on the way to the cochlea

you can replace the bones or get a hearing aid to help

Nerve (sensorineural) Deafness:

 the hair cells in the cochlea get damaged

can be caused by loud noises

hairs are irreplaceable

cochlea implant is possible

Smell and Taste

-sensory interaction:

the principle that one sense may influence another

Taste

-we have bumps on our tongue called papillae

-taste buds are located on the papillae (all over the mouth)

-sweet, salty, sour, bitter, spice

-Umami:

 flavorful, meaty, savory taste

Touch

-receptors located in our skin

-Gate Control Theory of Pain:

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass onto the brain

-Vestibular Sense:

tells us where our body is oriented in space; our sense of balance

-Kinesthetic Sense:

 tells us where our body parts are; receptors located in our muscles and joints