sensation and perception

sensation

the physical processing of environmental stimuli by the sense organs

transduction

the conversion of one form of energy into another

perception

the psychological process of interpreting sensory information

absolute threshold

the smallest amount of stimulation needed for detection by a sense

signal detection

method for studying the ability to correctly identify sensory stimuli

differential threshold / just noticeable difference (JND)

the smallest difference needed in order to differentiate two stimuli

just noticeable difference (JND) / differential threshold

the smallest difference needed in order to differentiate two stimuli

weber’s law

states that just noticeable difference is proportional to the magnitude of the initial stimulus

bottom-up processing

building up to perceptual experience from individual pieces

top-down processing

experience influencing the perception of stimuli

sensory adaptation

decrease in sensitivity of a receptor to a stimulus after constant stimulation

retina

cell layer in the back of the eye containing photoreceptors

binocular disparity

difference in images processed by the left and right eyes

binocular vision

our ability to perceive 3D and depth because of the difference between the images on each of our retinas

rods

photoreceptors of the retina sensitive to low levels of light. located around the fovea

cones

photoreceptors of the retina sensitive to color. located primarily in the fovea

primary visual cortex

area of the cortex involved in processing visual stimuli

agnosia

loss f the ability to perceive stimuli

ventral pathway

pathway of visual processing the “what” pathway

dark adaptation

adjustment of eye to high levels of light

light adaptation

adjustment of eye to high levels of light

trichromatic theory

theory proposing color vision as influences by three difference cones responding preferentially to red, green, and blue

opponent-process theory

theory processing color vision as influenced by cells responsive to pairs of colors

sound waves

changes in air pressure the physical stimulus for audition

audition

ability to process auditory stimuli. also called hearing

pinna

outermost portion of the ear

auditory canal

tube running from the outer ear to the middle ear

tympanic membrane

thin, stretched membrane in the middle ear that vibrates in response to sound. also called the eardrum

ossicles

a collection of 3 small bones in the middle ear that vibrate against the tympanic membrane

cochlea

spiral bone structure in the inner ear containing auditory hair cells

auditory hair cells

receptors in the cochlea that transduce sound into electrical potentials

primary auditory cortex

area of the cortex involved in processing auditory stimuli

vestibular system

parts of the inner ear involved in balance

mechanoreceptors

mechanical sensory receptors in the skin that response to tactile stimulation

primary somatosensory cortex

area of the cortex involved in processing somatosensory stimuli

somatotopic map

organization of the primary somatosensory cortex maintaining a representation of the arrangement of the body

nociception

our ability to sense pain

phantom limbs

the perception that a missing limb still exists

phantom limb pain

pain in a limb that no longer exists

chemical senses

our ability to process the environmental stimuli of smell and taste

olfaction

ability to process olfactory stimuli also called smell

gustation

ability to process gustatory stimuli. also called taste

odorants

chemicals transduced by olfactory receptors

olfactory epithelium

organ containing olfactory receptors

shape theory of olfaction

theory proposing that odorants of difference size and shape correspond to different smells

anosmia

loss of the ability to smell

taste receptor cells

receptors that transduce gustatory information

taste receptor cells

receptors that transduce gustatory information

tastants

chemicals transduced by taste receptor cells

flavor

the combination of smell and taste

multimodal perception

the effects that concurrent stimulation in more than one sensory modality has on the perception of events and objects in the world

superadditive effect of multisensory integration

the finding that responses to mulimodal stimuli are typically greater than the sum of the independent responses to each unimodal component if i were presented on its own

principle of inverse effectiveness

the finding that, in general, for a multimodal stimulus, if the response to each unimodal component (on its own) is weak, then the opportunity for multisensory enhancement is very large. however, of one component—by itself—is sufficient to evoke a strong response, than the effect of the response gained by simultaneously processing the other components of the stimulus will be relatively small