Sensory: Sensation Marshall 210

Sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

Perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

supraliminal stimuli

stimuli that are strong enough to be consistently perceived

subliminal stimuli

stimuli that are below the level of conscious awareness

internal noise

the spontaneous random firing of nerve cells that occurs because the nervous system is always active

Sensitivity

Ability to recognize and appreciate the personal characteristics of others
Intensity of the singal
Capacity of sensory systems
Affected by noise level
From background stimulation
From random neural activity

response bias

tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

response criterion

the internal rule a person uses to decide whether or not to report a stimulus

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time

sensory systems

the parts of the nervous system that provide information about the environment

vestibular sense

the sense of body movement and position, including the sense of balance

kinesthetic sense

sense of the location of body parts in relation to the ground and each other

physical properties of light

amplitude: height
wavelength: frequency
purity: purity of wave

properties of the visual system

brightness or light intensity: amplitude
hue: wavelength or frequency
saturation: purity of wave

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

physical properties of a wave

Structures of an eye

pupil

the adjustable opening in the center of the eye through which light enters

iris

adjustable muscle that causes pupil to dilate or constrict allows light to enter the eye

lens

the transparent structure behind the pupil that changes shape to help focus images on the retina

Retina

the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

Rods

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond

Cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

Fovea

the central focal point in the retina, around which the eye's cones cluster

bipolar and horizontal cells

two types of cells in the intermediate layer

Myopia (nearsightedness)

occurs when the image is focused in front of the retina

hyperopia(farsightedness)

light rays focused beyond retina, corrected with convex lens

presbyopia

farsightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age.

astigmatism

defective curvature of the cornea or lens of the eye

trichromatic color theory

The theory of color vision that holds that all color perception derives from three different color receptors in the retina (red, green, and blue receptors).

opponent-process theory

the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green

George Wald

three types of cones in the retina that are sensitive to different wavelengths

Frequency

number of soundwaves per time cycle

hertz

Unit of frequency per second

Amplitude

the vertical size of sound waves

Decibels

a measure of the physical compression of molecules that occur in an eardrum

pitch

frequency or wavelength

timbre

purity of frequency

auditory transduction

the process through which sound waves and sound info is passed through each part of the ear

middle ear bones

malleus (hammer), incus (anvil), stapes (stirrup)

malleus (hammer)

a small bone in the middle ear that transmits vibrations of the eardrum to the incus.

Incus (anvil)

The middle bone which is connected to the other two, passes vibrations onto the stapes.

stapes (stirrup)

transmits and amplifies vibrations from the incus to the oval window

cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

basilar membrane

A structure that runs the length of the cochlea in the inner ear and holds the auditory receptors, called hair cells.

Organ of Corti

Center part of the cochlea, containing hair cells, canals, and membranes

Intensity (loudness)

Amount of energy in a wave; determined by the amplitude, relates to perceived loudness

conduction deafness

An inability to hear resulting from damage to structures of the middle or inner ear.
can be helped with hearing aids

nerve deafness

Hearing loss created by damage to the hair cells or the auditory nerve fibers in the inner ear.
cannot be helped with hearing aids: bc of disease or loud sounds