module 7

psychology

Sensation

Sensation

the process by which sensory systems and the nervous system receive stimuli from our environment; awareness of the world

Bottom up processing

information processing that analyzes the raw stimuli entering through the many sensory systems.

Perception

the process of organizing and interpreting incoming sensory information

Top down processing

information processing that draws on expectations and experiences to interpret incoming sensory information

Absolute threshold

the minimum amount of stimulation needed to detect a particular stimulus; amount of stimulus a person can detect 50% of the time

Difference threshold

Minimum amount of difference needed to detect that two stimuli are not the same; noticeable difference

Single detection theory

theory that predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise)

Sensory adaptation

diminished sensitivity to constant and unchanging stimulation; If a stimulus is constant and unchanging, eventually a person may fail to respond to it

Selective attention

focusing conscious awareness on a particular stimulus to the exclusion of others; The ability to focus on one stimulus at a time

Cornea

the clear, curved bulge on the front of the eye that bends light rays to begin focusing them; protects the eye

Iris

a ring of muscle tissue that forms the colored portion of the eye and regulates the size of the pupil; A change in size allows more or less light to enter the eye

Pupil

the adjustable opening in the center of the iris, which controls the amount of light entering the eye

Lens

a transparent structure behind the pupil in the eye that changes shape to focus images on the retina

Retina

the light-sensitive surface at the back of the eyeball; Contains cells that convert light energy to nerve impulses; Made up of three layers of cells, Receptor cells, Bipolar cells, Ganglion cells

Receptor cells

specialized cells in every sensory system of the body that can turn other kinds of energy into action potentials (neural impulses) that the brain can process

Rod

visual receptor cells located in the retina that can detect only black, white, and gray

Cones

visual receptor cells located in the retina that can detect sharp details and color; Need more light than the rods; Many cones are clustered in the fovea

Optic nerve

the nerve that carries visual information from the eye to the occipital lobes of the brain

Blind spot

the point at which the optic nerve travels through the retina to exit the eye; the lack of rods and cones at this point creates a small blind spot

Trichromatic theory

a theory of color vision that says cones are sensitive to red, green, or blue – the three colors that combine to create millions of color combinations

Opponent process theory

a theory of color vision that says color is processed by cones organized in opponent pairs (red-green, yellow-blue, and black-white); light that stimulates one half of the pair inhibits the other half

Pitch

a sound’s highness or lowness, which depends on the frequency of the sound wave; measured as hertz (hz)

Cochlea

the major organ of hearing; a snail-shaped, bony, fluid-filled structure in the inner ear where sound waves are changed in neural impulses

Hair cells

the receptor cells for hearing; these are located in the cochlea and are responsible for changing sound vibrations into neural impulses

Auditory nerve

the nerve that carries sound information from the ears to the temporal lobes of the brain

Kinesthetic sense

he system for sensing the position and movement of individual body parts; Relies on receptor cells from the muscles and joints; One’s leg “falling asleep” is a disruption of the kinesthetic sense

Vestibular sense

the system for sensing body orientation and balance, which is located in the semicircular canals of the inner ear; Relies on fluid in the canals; Spinning in circles disrupts the fluid making one dizzy

Wave lengths

the distance between successive peaks in a wave motion of a given frequency

ganglion cells

the final output neurons of the vertebrate retina; provide information important for detecting the shape and movement of objects.

Hammer, anvil and stirrup

ossicles, Three tiny bones that transfer sound waves from the eardrum to the cochlea

What are the four sensations of touch

pressure, hot, cold, and pain

Gate-control theory

a mechanism, in the spinal cord, in which pain signals can be sent up to the brain to be processed to accentuate the possible perceived pain, or attenuate it at the spinal cord itself.