AP Psychology: Topic 1.6 - Sensation

Sensation

the process of the sensory organs transforming physical energy into neurological impulses the brain interprets as the five senses of vision, smell, taste, touch, and hearing

Transduction

the process of converting outside stimuli, such as light, from a sensory signal into neural activity

Absolute threshold

the minimum intensity of stimulation needed to detect a sensation 50 percent of the time

Just-noticeable difference

the amount a stimulus must be changed in order for a difference to be noticeable

Sensory adaptation

tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging

Weber's law

to be perceived as different, two stimuli must differ by a constant minimum percentage

Sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

Synesthesia

a neurological condition in which information meant to stimulate one of your senses stimulates several of your senses (e.g., hearing the word "cat" but perceiving the color green)

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

Blind spot

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

Visual nerve

the optic nerve; comprised of millions of nerve fibers that send visual messages to the brain

Lens

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

Sensorineural deafness

deafness that usually results from damage to the inner ear or to the auditory nerve

Olfactory system

the sensory system for smell

Thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Pheromones

chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species

Gustation

the sensation of taste resulting from the action of chemicals on the taste buds

Taste receptors

chemical receptors on the tongue that decode molecules of food or drink to identify them (sweet, salty, bitter, oleogustus (oily, fatty), and umami)

Supertasters

people with the most number of tastebuds and have the highest sensitivity to all tastes, as well as mouth sensations in general

Medium Tasters

people with an average number of taste buds; they represent 50% of the population

Nontasters

people with fewer tastebuds who are not so sensitive to taste; they prefer sweeter or fattier foods to maximize taste

Warm/cold receptors

thermoreceptors are able to detect heat and cold and are found throughout the skin in order to allow sensory reception throughout the body

Gate control theory

theory that explains how spinal nerves block or allow pain signals to pass to the brain

Phantom limb

perceived sensation, following amputation of a limb, that the limb still exists

Vestibular sense

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

Semicircular canals

three tiny, fluid-filled tubes in the inner ear that help a person maintain balance

Kinesthesis

the sense that provides information about the position and movement of individual body parts

Accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina

Nearsightedness

a condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina

Farsightedness

a condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind the retina

Photoreceptors

rods and cones in the eye; they respond to light

Rods

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

Cones

three types of photoreceptors (blue, green, red) responsible for color vision and color sensitivity

Trichromatic theory

the theory that human eyes only perceive three colors of light: red, blue, and green

Opponent-process theory

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

Afterimages

images that occur when a visual sensation persists for a brief time even after the original stimulus is removed

Ganglion cells

specialized cells behind the bipolar cells whose axons form the optic nerve which takes the information to the brain

Dichromatism

when only two of the three cone types are present or functional; red and green, for example, may appear the same

Monochromatism

when only one of the three cone types is present or functional; no color can be perceived (colorblindness)

Prosopagnosia

inability to recognize faces (face blindness)

Blindsight

the ability of individuals with blindness to detect and respond to visual stimuli despite lacking awareness of having seen anything

Wavelength

the distance between two corresponding parts of a wave

Pitch

the highness or lowness of a sound, as determined by the frequency of the sound waves

Amplitude

the height of a wave's crest

Loudness

how strong or soft a sound seems to a listener; determined by the intensity or amount of energy

Pitch perception

the aspect of hearing that allows us to tell how high or low a given tone is

Place theory

the theory that a person hears different pitches because of vibrations in specific places on the basilar membrane of the cochlea

Volley theory

the theory that groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain

Frequency theory

the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone (e.g., a tone measuring 600 hertz will be transduced into 600 nerve impulses a second)

Sound localization

when the brain locates the direction a sound originated from based on which ear the sound strikes first

Conduction deafness

hearing loss caused by damage to the mechanical system that conducts sound waves to the cochleaConduction deafness