Sensation and Perception

Sensation

the physical processing of environmental stimuli by the sense organs

Transduction

the conversion of one form of energy into another

physical energy such as light or a sound wave is converted into a form of energy the brain can understand: electrical stimulation

Perception

psychological process of interpretating sensory information

Absolute threshold

The smallest amount of stimulation needed for detection by a sense

Agnosia

Loss of the ability to percieve stimuli

Anosmia

Loss of the ability to smell

Audition

Ability to process auditory stimuli. Also called hearing

auditory Canal

Tube running from the outer ear to the middle ear

Auditory hair cells

Receptors in the cochlea that transduce sound into electrical potentials

Binocular disparity

Difference is 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

Bottom-up processing

Building up to perceptual experience from individual pieces

Chemical senses

Our ability to process the environmental stimuli of smell and taste.

Cochlea

Spiral bone structure in the inner ear containing auditory hair cells

Cones

Photoreceptors of the retina sensitive to color. Located primarily in the fovea

Dark adaptation

Adjustment of eye to low levels of light

Differential threshold (difference threshold)

The smallest difference needed in order to differentiate two stimuli. (See Just Noticeable Difference (JND))

Dorsal pathway

Pathway of visual processing. The “where” pathway

Flavor

the combination of smell and taste

gustation

ability to process gustatory stimuli (aka taste)

just noticeable difference (JND)

The smallest difference needed in order to differentiate two stimuli. (see Differential Threshold)

light adaptation

Adjustment of eye to high levels of light.

mechanoreceptors

Mechanical sensory receptors in the skin that response to tactile stimulation.

multimodal perception

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

Nociception

our ability to sense pain

Odorants

Chemicals transduced by olfactory receptors

Olfaction

Ability to process olfactory stimuli (aka smell)

Olfactory epithelium

organ containing olfactory receptors

opponent-process theory

Theory proposing color vision as influenced by cells responsive to pairs of colors.

ossicles

A collection of three small bones in the middle ear that vibrate against the tympanic membrane

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

pinna

outermost portion of the ear

primary auditory cortex

area of the cortex involved in processing auditory stimuli

primary somatosensory cortex

area of the cortex involved in processing somatosensory stimuli

primary visual cortex

area of the cortex involved in processing visual stimuli

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, if one component—by itself—is sufficient to evoke a strong response, then the effect on the response gained by simultaneously processing the other components of the stimulus will be relatively small.

Retina

cell layer in the back of the eye containing photoreceptors (rods + cones)

rods

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

sensation

the physical processing of environmental stimuli by the sense orgrans

sensory adaptation

Decrease in sensitivity of a receptor to a stimulus after constant stimulation.

Shape theory of olfaction

Theory proposing that odorants of different size and shape correspond to different smells.

Somatosensation

ability to sense touch, pain, and temperature

Somatotopic map

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

Sound Waves

Changes in air pressure. The physical stimulus for audition.

Superadditive effect of multisensory integration

The finding that responses to multimodal stimuli are typically greater than the sum of the independent responses to each unimodal component if it were presented on its own.

Tastants

Chemicals transduced by taste receptor cells.

Taste receptor cells

Receptors that transduce gustatory information.

Top-down processing

Experience influencing the perception of stimuli.

(pattern recognition)

we look for patterns to prevent danger

Transduction

The conversion of one form of energy into another

Trichromatic Theory

Theory proposing color vision as influenced by three different cones responding preferentially to red, green and blue.

Tympanic membrane

Thin, stretched membrane in the middle ear that vibrates in response to sound. Also called the eardrum.

Ventral pathway

pathway of visual processing

the “what” pathway

vestibular system

parts of the inner ear involved in balance

weber’s law

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

Lens

part of the eye that focuses