AP Psych Unit 4

Sensation

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

Sensory receptors

Specialized nerve cells that detect physical stimuli from the environment.

Perception

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

Bottom-up processing

Processing that begins with sensory input and builds up to the brain’s interpretation.

Top-down processing

Processing guided by experience and expectations to interpret sensory input.

Selective attention

Focusing conscious awareness on a particular stimulus.

Inattentional blindness

Failing to see visible objects because attention is directed elsewhere.

Change blindness

Failing to notice changes in the environment.

Transduction

Converting stimulus energies into neural impulses.

Psychophysics

The study of how physical energy relates to psychological experiences.

Absolute threshold

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

Signal detection theory

A theory predicting how and when we detect faint stimuli amid background noise; assumes no single absolute threshold.

Subliminal

Stimuli that are below conscious awareness.

Priming

Unconscious activation of associations that influence perception or response.

Difference threshold

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

Weber’s law

Two stimuli must differ by a constant minimum percentage to be perceived as different.

Sensory adaptation

Reduced sensitivity due to constant stimulation.

Perceptual set

A mental predisposition to perceive something in a particular way.

Extrasensory perception (ESP)

The claim that perception can occur apart from sensory input.

Parapsychology

The study of paranormal phenomena like ESP.

Wavelength

The distance between light or sound wave peaks; determines color (hue) in vision.

Hue

The color we experience, determined by wavelength.

Intensity

The amount of energy in a light or sound wave; influences brightness or loudness.

Cornea

The clear outer layer of the eye that bends light.

Pupil

The adjustable opening in the center of the eye.

Iris

The colored ring of muscle that controls pupil size.

Lens

The structure that changes shape to focus images on the retina.

Retina

The light-sensitive inner surface of the eye containing rods, cones, and neurons.

Accommodation

The lens changing shape to focus near or far objects.

Rods

Retinal receptors that detect black, white, and gray; needed for peripheral and dim vision.

Cones

Retinal receptors near the fovea that detect color and fine detail.

Optic nerve

The nerve that carries visual information to the brain.

Blind spot

The area where the optic nerve leaves the eye; no receptor cells.

Fovea

The central focus point in the retina where cones cluster.

Parallel processing

Processing multiple aspects of a stimulus simultaneously.

Young-Helmholtz trichromatic theory

The theory that the retina has three types of color receptors—red, green, and blue.

Opponent-process theory

The theory that color vision is based on opposing retinal processes (red–green, blue–yellow, black–white).

Gestalt

An organized whole; the idea that we integrate pieces of information into meaningful forms.

Figure-ground

Organizing the visual field into objects (figures) and background (ground).

Grouping

The perceptual tendency to organize stimuli into coherent groups.

Depth perception

The ability to see in three dimensions and judge distance.

Visual cliff

A device used to test depth perception in infants and animals.

Binocular cues

Depth cues that require two eyes.

Retinal disparity

A binocular cue for depth based on the difference between images from each eye.

Monocular cues

Depth cues available to either eye alone.

Phi phenomenon

The illusion of movement created by rapidly flashing lights.

Perceptual constancy

Perceiving objects as unchanging even when lighting and retinal images change.

Color constancy

Perceiving objects as having consistent color despite different lighting.

Perceptual adaptation

Adjusting to a displaced or inverted visual field.

Audition

The sense of hearing.

Frequency

The number of wavelengths per second; determines pitch.

Pitch

A tone’s highness or lowness.

Middle ear

The chamber containing the eardrum and three tiny bones that concentrate vibrations.

Cochlea

A fluid-filled, snail-shaped structure in the inner ear where sound waves trigger nerve impulses.

Inner ear

The innermost part of the ear, containing the cochlea and vestibular organs.

Sensorineural hearing loss

Hearing loss caused by damage to the cochlea’s receptor cells or the auditory nerve.

Conduction hearing loss

Hearing loss caused by damage to the mechanical system that transmits sound waves.

Cochlear implant

A device that converts sounds into electrical signals to stimulate the auditory nerve.

Place theory

The theory that pitch corresponds to the place where the cochlea’s membrane is stimulated.

Frequency theory

The theory that pitch is related to the rate of nerve impulses traveling up the auditory nerve.

Gate-control theory

The theory that the spinal cord contains a “gate” that blocks or allows pain signals.

Olfaction

The sense of smell.

Kinesthesia

The sense of movement and position of body parts.

Vestibular sense

The sense of balance and head movement, based on inner-ear structures.

Sensory interaction

When one sense influences another (e.g., smell alters taste).

Embodied cognition

How bodily sensations and actions affect thoughts and judgments.