Unit 3: Sensation and Perception

AP Psychology unit 3 with Miss Larochelle (HMHS)

Just Noticeable Difference (JND)

The smallest change in the intensity of a stimulus that can be detected.

Synesthesia

Stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.

Opponent-process theory

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

Ganglion Cells

Neurons in the retina that receive visual information from bipolar cells and transmit it to the brain via the optic nerve.

Nearsightedness

When you can see objects close to you clearly, but objects farther away are blurry.

Farsightedness

The condition where you can see distant objects clearly, but close ones are blurry.

Dichromatism

A type of color vision deficiency where a person has only two types of the three normal cone photoreceptors functioning in the retina.

Monochromatism

Total color blindness, where an individual can only perceive shades of gray.

Blindsight

The ability of people who are clinically blind to respond to visual stimuli that they do not consciously see.

Prosopagnosia

"Face blindness," a neurological disorder characterized by the inability to recognize faces.

Schemas

Mental frameworks or structures that help us organize and interpret information.

Convergence

The inward movement of our eyes when we focus on close objects.

Relative Clarity

A depth cue where clearer objects are perceived as closer.

Relative Size

A visual cue where closer objects appear larger than those further away.

Texture Gradient

The perception of texture becoming denser and finer as it recedes into the distance.

Linear Perspective

A depth cue where parallel lines appear to converge as they recede into the distance.

Interposition

When one object overlaps another, leading us to perceive the overlapping object as closer.

Shape Constancy

The ability to perceive an object as having the same shape despite changes in angle or distance.

Size Constancy

The perception that an object remains the same size despite changes in distance.

Color Constancy

The ability to perceive colors of objects as stable under varying lighting conditions.

Apparent Movement

The perception of motion when there isn't any actual movement.

Amplitude

The measure of the intensity or loudness of a sound wave.

Wavelength

The distance between sound wave peaks.

Volley Theory

A theory of pitch perception proposing that groups of auditory neurons fire in rapid succession to encode high-frequency sounds.

Sound Localization

The brain's ability to determine the location of a sound source in space.

Olfactory Systems

Responsible for smell, detecting odors and sending signals to the brain.

Pheromones

Chemical substances released by animals that trigger social or behavioral responses in others of the same species.

Supertasters

Individuals highly sensitive to taste, experiencing flavors more intensely.

Medium Tasters

Individuals with average sensitivity to taste, experiencing flavors moderately.

Nontasters

Individuals less sensitive to taste, experiencing flavors less intensely.

Warm/Cold Receptors

Specialized sensory neurons that detect changes in temperature.

Pain

The body's message indicating something has gone wrong, an emotional response to stimuli.

Semicircular Canals

Fluid-filled structures in the inner ear that detect rotational movements of the head.

Gustation

The sense of taste, involving receptors on the tongue that detect different flavors.

Phantom Limb

Sensation of pain or other feelings in a missing limb due to the brain's continued perception of it.

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our 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 or sensory information

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectation

selective attention

the focusing of conscious awareness on a particular stimulus

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment

transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret

absolute threshold

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

Weber’s Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

sensory adaption

diminished sensitivity as a consequence or constant stimulation

perceptual set

a mental predisposition to perceive one thing and not the other

pupil

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

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil

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 the receptor rods and cones plus layers of neurons that begin the processing of visual information

accommodation

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

rods

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

cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. They detect fine detail and give rise to color sensations

optic nerve

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

blind spot

the point at which the optic nerve leaves the eye, where no receptor cells are located

fovea

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

Young-Helmholtz Trichromatic (three color) Theory

the theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which when stimulated in combination, can produce the perception of any color

Opponent-process Theory

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

gestalt

an organized whole. Psychologists of this field emphasize our tendency to integrate pieces of information into meaningful wholes

figure-ground

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

depth perception

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

binocular cues

depth cues, such as retinal disparity, that depend on the use of two eyes

retinal disparity

a binocular cue for perceiving depth: By comparing images from the retinas in the two eyes, the brain computes distance; the greater the disparity (difference) between two images, the closer the object

monocular cues

depth cues such as interposition and linear perspective, available to either eye alone

perceptual constancy

perceiving objects as unchanging (having consistent shapes, sizes brightness, and color) even as illumination and retinal images change

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object

pitch

a tone’s experienced highness or lowness; depends on frequency

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window

cochlea

a coiled, boy, fluid-filled tube in the inner ear, sound waves traveling through the fluid trigger nerve impulses

inner ear

the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs

sensorineural hearing loss

hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; also called nerve deafness

conduction hearing loss

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

Place Theory

in hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated

Frequency Theory

in hearing, the theory that the rate of nerve impulses traveling up the auditory nerves matching the frequency of a tone, thus enabling us to sense its pitch

Gate-Control Theory

the theory that the spinal cord contains a neurological “gate“ that blocks pain signals or allows them to pass on to the brain. The “gate“ is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain

kinesthesia

the system for sensing the position and movements of individual body parts

vestibular sense

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

sensory interaction

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