Psych - Senses

sensation

process in which sense organ receptors are stimulated and that information is sent to the brain

sensory adaptation

loss of responsiveness in receptor cells after stimulation has remained unchanged for a while 

absolute threshold

minimum level of stimuli needed to excite perceptual system

different threshold (JND)

the amount of stimulus change needed for one to detect a change at least 50% of the time

Method of Limits

values of stimuli are presented in ascending or descending order; test level at which stimuli can be detected

Method of constant stimuli

values of a signal are presented in random order; tests absolute and difference threshold 

Weber’s law

the size of JND is proportional to intensity of stimulus

Fechner’s law

allows an estimate of the magnitude of the stimulus and expresses relationship between actual magnitude and perceived magnitude of stimuli

Steven’s Power Law

more accurate version of Fechner’s Law, especially for pain and temperature 

subliminal perception

stimuli are below the threshold of awareness, but perception occurs outside of conscious experience

Cocktail Party Phenomenon

you cannot hear all of the conversations in a party, but you can notice if you hear your name from across the room

Allocation

to apportion for specific attention, to use netal resources for attention

Filter Theory

information is screened out due to limited processing ability

Attenuation theory

all information is analyzed but factors inhibit attention so not all information is processed

Transduction 

transformation of one form of energy into another; stimulus information into nerve impulses

Synesthesia

a neurological condition where stimulating one sense triggers an involuntary experience in another sense, resulting in perceptions like seeing colors when hearing music

McGurk effect

a perceptual phenomenon and auditory illusion where visual information from lip movements conflicts with auditory information, causing the brain to perceive a third, different sound than what was actually spoken

cornea

small transparent bulge covering the pupil/iris

pupil

dark opening at the center of the eye

Iris

pigmented part of the eye

Lens

part behind pupil

retina

light-sensitive layer at the back of the eyeball

photoreceptors

light-sensitive cells in the retina that convert light energy to neural impulses

Rods

sensitive to dim light but not colors

cones

sensitive to colors but not dim light

Duplicity

the retina has two different receptor systems (rods and cones)

Optic nerve

bundle of neurons that carry visual information from retina to brain 

Fovea

area of sharpest vision in retina

Blindspot

There are no photoreceptors where the optic nerve exits the eyeball

nearsighted/myopic

one can see things clearly up close (elongated eyeballs)

farsighted/hyperopic

One can see things clearly far away (shortened eyeballs)

visual activity test

measures the ability to see fine detail and visual clarity

Bipolar cells

layer of the retina that collect neural impulses from photoreceptor and shuttles them to ganglion cell layer

Ganglion cells

layer of the retina that gathers neural impulses from the bipolar layer and the axons make up the optic nerve

Lateral Geniculate Nucleus 

region of the thalamus that receives fibers from the cone-rich area of the retina and relays messages to the visual cortex

Striate cortex

first area of visual cortex to recieve visual input from the thalamus

Optic chiasm

X-shaped structure formed by the crossing of the optic nerves in the brain

parallel processing

brain simultaneously processes parts on an image

sequential processing

brain uses a step-by-step linear processing of an image

dark adaptation

increase in the sensitivity of light when illumination goes from high to low

receptive fields

specialized areas of the retina that produce a firing of cells in the visual system 

prosopagnosia

special type of agnosia resulting in an inability to recognize faces

saccades

rapid voluntary movements of the eyes

perceptual span

size of the region a person sees while fixating visually

Hue

psychological sensation derived from the wavelength of visible color

Brightness

psychological sensation caused by the intensity of light waves

saturation

depth of hue determined by homogeneity of wavelengths 

trichromats

people with normal color vision who have all three types of cones

trichromatic theory

There are three types of cones that are sensitive to red, blue, and green wavelengths

opponent-process theory

Three types of cones process color in complementary pairs. all fire, but one is stronger (red-green, yellow-blue, black-white)

Dichromats

one can only perceive 2 of 3 basic colors

monochromats

no colors are perceived

tetreachromats

4 cones instead of 3; can see more color than normal

afterimages

sensation that lingers after the stimulus is removed

cornea

1

pupil

2

Iris

3

Lens

4

optic nerve

6

retina

7

sound

psychological experience that occurs as changes in air pressure stimulate the receptive organ for hearing

frequency

number of cycles completed by a wave in a given amount of time

Amplitude

physical strength of a wave

Tympanic membrane

the eardrum

ossicles

Hammer (malleus), anvil (ineus), stirrup (stapes)

cochlea

where sound waves are transduced

basilar membrane

thin strip of tissue sensitive to vibrations

auditory nerve

neural pathway connecting the ear and the brain

Pitch

sensory characteristic of sound produced by the frequency of the sound wave 

Volume

sensory characteristic of sound produced by the amplitude os a sound wave

timbre

quality of a sound wave that derived from the waves complexity

conduction deafness

inability to hear resulting from damage to structures of the middle or inner ear; cochlea not getting info

nerve deafness

inability to hear linked to a deficit in the body’s ability to transmit impulses from the cochlea to the brain; auditory nerve

audiogram

graph showing hearing sensitivity at selected frequencies

place theory

states that our perception of sound depends on where each frequency produces vibrations along the basilar membrane

frequency theory

states that the frequency of the auditory nerve impulses corresponds to the frequency of a tone, which allows us to detect pitch

volley theory

states that groups of neurons in the auditory system fire action potentials in rapid, overlapping succession    to encode sound frequencies that exceed the firing rate of any single neuron

interaural time difference

sound reaches ears at different intensities due to space

interaural intensity difference

sound coming from left will be louder in left ear

vestibular sense

sense of body orientation with respect to gravity

kinesthetic sense

sense of body position and movement of body parts relative to each other

epidermis

outer layer of the skin

dermis

layer under epidermis; contains live cells, nerve endings, blood, hair cells, and sebaceous glands

hypodermis

underlayer; thick insulating cushion

gate-control theory

There are “neural gates” that can block incoming pain impulses across the “gates”

olfaction

sense of smell

pheromones

chemical signals released by organisms to communicate with other members of the species 

gustation

sense of taste

taste buds

receptors for taste

papillae

bumps on your tongue

sweet, sour, salty, bitter, umami, oleogustus

What are the different tastes?

phantom limb sensation 

the perception of sensations, such as pain, tingling, or warmth, in a limb that has been amputated or lost

semicircular canals

three fluid-filled tubes in the inner ear that work together to detect head rotation and maintain balance

outer ear

1

hammer

2

anvil

3

semicircular canals

4

vestibular nerve

5

auditory nerve

6

cochlea

7