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Sensation
Chapter 3
Question | Answer |
---|---|
Sensation | the act of detecting external stimuli and converting them into nervous-system activity |
Transducer | a mechanism that converts energy from one form into another |
Perception | a process that involves the selection, organization, and interpretation |
Sensory threshold | the minimum intensity of a stimulus required to act |
psychophysics | the study of the relationship btw. the physical characteristics of stimuli and the psychological experience they produce |
absolute threshold | the physical intensity of a stimulus that is detected 50 % of the time |
signal detection theory | the notion that stimulus detection is a decision-making process of determining if a signal exits against a background of noise |
difference threshold | the smallest difference btw. two stimuli that can be detected 50% of the time |
just noticable difference (jnd) | the amount of change ina stimulus attribute that makes it just detectably different from what it was |
sensory adaptation | the process by which the visual receptors become more sensitive with time spent in the dark |
light adaptation | the process by which the visual receptors rapidly become less sensitive as one moves from a dark area to a lighted one |
cornea | the outermost structure of the eye, protecting it and bending light waves to focus an image on the retina |
pupil | the opening in the iris of the eye through which light passes into the eye |
iris | the colored part of teh eye, which contracts or expands to let in varying amounts of light from the enviroment |
lens | the flexible structure of teh eye that focuses images onto the retina |
accommodation | in vision, the process of the ciliary muscles changing the shape of the lens to focus images |
aqueous humor | the fluid that provides nourishment to teh cornea and other structures at the front of the eye |
vitreous humor | a thick fluid in the middle of teh eyeball responsible for keeping its spherical shape |
retina | a series of layers of cells at the very back of the eye where light is transduced into neural imulses, collected, and moved out of the eye |
rods | the photoreceptors in the periphery of the retina responsible for reacting to low levels of illumination, but without discriminating colors or hues |
cones | the photoreceptors in the middle of the retina responsible for most normal vision and color vision |
optic nerve | the collection of neural fibers that leaves the eye on the way back to the occipital lobe |
fovea | a small indentation in the middle of the retinacontaining (mostly) cones; where acuity is best |
blind spot | that small area of each eye where the optic nerve leaves the retinal area and no vision occurs |
optic chiasma | that structure in the middle of teh brain where fibers carrying impulses from the right visual field are directed to teh left side of the brain and vice versa |
trichromatic theory | the theory of color vision associated with Helmholtz that proposes three types of receptors, one for each of the primary colors of light: red, green, and blue |
opponent-process theory | the theory of color vision associated with Hering that proposes mechanism that process blue and yellow, red and green, and black and white |
eardrum | the membrane at the outermost portion of teh ear, set in motion by vibrations from the enviroment |
malleas, incus, stapes | the three small bones of teh middle ar that intensity and convey vibrations from the eardrum to the oval window |
cochlea | the snail-shaped structure that is the inner ear, where transduction occurs |
basilar membrane | a tissue that runs the length of teh inside of the cochlea and that moves as the fluid in the cochlea vibrates |
hair cells | sensory neurons, teh transducers for hearing in the cochlea |
taste buds | the receptors cells for taste, located in the surface of the tongue |
pheromones | chemicals that produce distinctive odors, usually associated with sexuality |
vomeronasal organ (VNO) | the particular organ that detects the presence of pheromones |
vestibular sense | the position sense that informs us about balance, or relation to gravity, and acceleration and deceleration |
kinesthetic sense | located in the joints, the position sense that inorms us about the location and movement of our own body parts |
placebo | inthe context of treatment, a substance that a person believes will be useful in treating some substance although it contains no active ingredients |