sensation & perception vocab

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies.

Perception

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

Absolute threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time.

Difference threshold

The minimum difference between two stimuli required for detection 50% of the time.

Weber’s law

The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage.

Fechner’s law

The logarithmic relationship between the magnitude of a stimulus and its perceived intensity.

Signal detection theory

A theory that predicts how and when we detect the presence of a faint stimulus amid background stimulation.

Adaptation

The diminished sensitivity to a stimulus as a consequence of constant stimulation.

Habituation

A decrease in responsiveness to a stimulus after repeated presentations.

Perceptual set

A mental predisposition to perceive one thing and not another.

Selective attention

The focusing of conscious awareness on a particular stimulus.

Parts of the eye (pathway of light)

Light enters through the cornea, passes through the pupil, is focused by the lens, and forms an image on the retina.

Rods

Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision.

Cones

Retinal receptor cells that are concentrated near the center of the retina and function in daylight or in well-lit conditions.

Visual agnosia

The inability to recognize objects, shapes, or faces despite intact vision.

Trichromatic theory

The theory that the retina contains three different color receptors — one most sensitive to red, one to green, and one to blue.

Opponent processing theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

Subtractive vs. additive color mixing

Subtractive mixing involves the absorption of light (mixing pigments), whereas additive mixing involves the combination of light sources.

Phi phenomenon

An illusion of movement created when two or more adjacent lights blink on and off in quick succession.

Figure-ground perception

The ability to distinguish objects from their backgrounds.

Gestalt beliefs of perception

The belief that the whole is greater than the sum of its parts.

Binocular disparity and depth cues

The difference in images between the two eyes that allows for depth perception.

Monocular depth cues

Depth cues available to either eye alone, such as relative size and interposition.

Visual cliff

A laboratory device for testing depth perception in infants and young animals.

Perceptual constancies (shape, color, size)

The tendency to perceive objects as unchanging despite changes in sensory input.

Distal stimulus

An object or event in the world that reflects light or emits sound.

Proximal stimulus

The information registered by the sensory receptors when light or sound reaches them.

Feature Analysis theory

The theory that the brain detects specific elements of visual information such as edges and contrasts.

Nearsightedness vs. Farsightedness

Nearsightedness (myopia) is when distant objects are blurred, while farsightedness (hyperopia) is when nearby objects are unclear.

Parts of the ear (pathway of sound)

Sound waves enter through the outer ear, travel down the ear canal, vibrate the eardrum, and are transmitted through the middle ear to the cochlea.

Perceptive deafness

Hearing loss caused by damage to the inner ear or the auditory nerve.

Conductive deafness

Hearing loss caused by problems in the outer or middle ear that prevent sound from being conducted to the inner ear.

Vestibular system

The system in the inner ear that contributes to balance and spatial orientation.

Place theory

The theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

Volley theory

The theory that groups of auditory neurons can fire in volleys to convey the frequency of a sound.

Frequency theory

The theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone.

Cocktail party effect

The ability to focus one's auditory attention on a particular stimulus while filtering out other stimuli.

Dichotic listening

A psychological test that involves presenting different auditory stimuli to each ear.

Gustatory system

The sensory system for the sense of taste.

Olfactory system

The sensory system for the sense of smell.

Sensation of touch

The perception of pressure, temperature, and pain on the skin.

Oleogustus

The taste sensation of fat.

Gate control theory

The theory that suggests the spinal cord contains a neurological gate that can block pain signals or allow them to pass to the brain.

Kinesthetic system

The sensory system that provides information about body position and movement.

Synesthesia

A condition in which stimulation of one sensory modality leads to automatic, involuntary experiences in another sensory modality.

Prosopagnosia

The inability to recognize faces, even familiar ones, due to damage in the brain.

Pheromones

Chemical signals released by an individual that influence the behavior or physiology of others.

Phantom Limb Sensation

The phenomenon where individuals feel sensations, including pain, in an amputated or missing limb.