sensation and perception vocab list

Sensation

The process by which sensory receptors and the nervous system receive and represent stimulus energies from the environment.

Perception

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

Bottom-up Processing

Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information.

Top-down Processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

Transduction

The conversion of one form of energy into another, such as the transformation of stimulus energy into neural impulses the brain can interpret.

Psychophysics

The study of the relationship between physical characteristics of stimuli and our psychological experience of them.

Absolute Threshold

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

Difference Threshold (Just Noticeable Difference - JND)

The smallest difference between two stimuli that a person can detect 50% of the time.

Weber’s Law

The principle that the size of the just noticeable difference is a constant proportion of the original stimulus intensity.

Signal Detection Theory

A theory predicting how and when we detect the presence of a faint stimulus amid background noise; detection depends on experience, expectations, motivation, and alertness.

Subliminal

Below the threshold of conscious awareness; stimuli that are detected less than 50% of the time.

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Selective Attention

The focusing of conscious awareness on a particular stimulus while ignoring others.

Feature Detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Sensory Receptors

Specialized cells responsible for converting external stimuli into neural signals.

Light

Electromagnetic energy that is visible to the human eye.

Wavelength

The distance from the peak of one light wave to the peak of the next, determining the color we perceive.

Hue

The color of light, determined by the wavelength of the light.

Intensity

The amount of energy in light waves, determined by the wave’s amplitude, which influences brightness.

Pupil

The adjustable opening in the center of the eye through which light enters.

Lens

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

Retina

The light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin the processing of visual information.

Rods

Retinal receptors that detect black, white, and gray, responsible for peripheral and night vision.

Cones

Retinal receptors concentrated near the center of the retina that function in daylight and detect fine detail and color.

Optic Nerve

The nerve that carries neural impulses from the eye to the brain.

Fovea

The central focal point in the retina, around which the eye’s cones cluster.

Blind Spot

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

Sound Waves

Waves of air pressure that cause the sensation of sound.

Frequency

The number of complete wavelengths that pass a point in a given time; it determines pitch.

Pitch

A tone’s experienced highness or lowness, depending on the frequency of the sound wave.

Amplitude (Sound)

The height of a sound wave, which determines the loudness of the sound.

Eardrum (Tympanic Membrane)

A thin membrane that vibrates when sound waves hit it, transferring sound vibrations to the middle ear.

Ossicles

The three tiny bones in the middle ear (hammer, anvil, stirrup) that amplify sound vibrations.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear that transforms sound vibrations into neural messages.

Basilar Membrane

A membrane in the cochlea that contains hair cells, which are sensory receptors for sound.

Auditory Nerve

The nerve that carries neural impulses from the cochlea to the brain.

Perceptual Set

A mental predisposition to perceive one thing and not another.

Gestalt

An organized whole; Gestalt psychologists emphasized that the whole is greater than the sum of its parts.

Figure-Ground

The organization of the visual field into objects (figures) that stand out from their surroundings (the ground).

Proximity

A Gestalt principle stating that we group nearby figures together.

Similarity

A Gestalt principle stating that we group similar figures together.

Continuity

A Gestalt principle stating that we perceive smooth, continuous patterns rather than discontinuous ones.

Closure

A Gestalt principle stating that we fill in gaps to create a complete, whole object.

Depth Perception

The ability to see objects in three dimensions and judge distance.

Binocular Cues

Depth cues that depend on the use of two eyes, such as retinal disparity and convergence.

Retinal Disparity

A binocular cue for perceiving depth; by comparing images from the two eyes, the brain computes distance.

Convergence

A binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object.

Monocular Cues

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

Relative Size

A monocular cue that allows us to judge the size of an object based on its distance from us.

Linear Perspective

A monocular cue that shows parallel lines appear to converge as they get farther away.

Motion Parallax

A monocular cue for depth perception where closer objects appear to move faster than those farther away.

Perceptual Constancy

Perceiving objects as unchanging even as illumination and retinal images change.

Size Constancy

The perception that an object’s size remains constant despite changes in its distance from us.

Color Constancy

The perception that the color of an object remains consistent even if lighting changes.

Shape Constancy

The perception that an object maintains its shape despite changes in the angle of view.

Kinesthetic Sense

The sense of the position and movement of body parts.

Vestibular Sense

The sense of balance and spatial orientation, controlled by the inner ear’s semicircular canals.

Olfaction (Smell)

The sense of smell, processed by the olfactory receptors in the nose.

Gustation (Taste)

The sense of taste, which detects sweet, sour, salty, bitter, and umami flavors through receptors on the tongue.