AP Psychology - Sensation and Perception and Learning

sensation

basic experience of the stimulation of the body's senses

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.

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.

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time. taste - 1 gram of table salt in 500 liters of water; smell - 1 drop of perfume in a 3 room apartment; touch - wing of a bee falling on your cheek from 1 centimeter above you

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time. Also called the just noticeable difference (jnd).

just noticeable difference

same as difference threshold - the minimum difference between two stimuli required for detection 50 percent of the time.

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

subliminal

psychoanalytic defense mechanism by which people re-channel their unacceptable impulses into socially approved activities.

priming

the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.

Weber's law

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

sensory adaptation

diminished sensitivity as a consequence of constant stimulation.

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 brains can interpret. ex - molecules of skunk spray enter nose, transform to electric signal, and interpreted by brain as unpleasant odor.

wavelength

the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic versions of this vary from the short blips of cosmic rays to the long pulses of radio transmission.

hue

the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.

intensity

the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude.

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 opening.

lens

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

cornea

transparent protective coating over the front part of the eye

afterimage

sense experience that occurs after a visual stimulus has been removed

feature detectors

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

parallel processing

the processing of many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.

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; others are stimulated by red and inhibited by green. Explains color afterimage.

trichromatic

can mix red, blue, and green to perceive virtually any hue

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.

accomodation

Sensation - the process by which 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. These 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 and no receptor cells are located there.

fovea

the central focal point in the retina, around which the eye's cones cluster; has the greatest density of cones

audition

the sense or act of hearing.

frequency

the number of complete wavelengths that pass a point in a given time (for example, per second).

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.

ossicles

three tiny bones in the middle ear (hammer, anvil, stirrup)

cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses; completes final step to convert vibrations into sound sensations

inner ear

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

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 nerve matches the frequency of a tone, thus enabling us to sense its pitch.

conduction hearing loss

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

sensorineural hearing loss

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

cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

kinesthesis

the system for sensing the position and movement of individual body parts.

vestibular sense

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

gate-control theory

non-painful nerve impulses compete with pain impulses to reach the brain, creating a neural blockage; 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.

sensory interaction

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

olfactory cells

receptor neurons of the nose

gestalt

an organized whole. These type of psychologists emphasized 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).

Gestalt principles

proximity
similarity
continuity
connectedness
closure

proximity (gestalt)

objects or shapes that are close to one another appear to form groups (near each other)

similarity (gestalt)

when things look the same, they are perceived to be a group

continuity (gestalt)

the eye is compelled to move through one object to continue to another

connectedness (gestalt)

elements connected by uniform visual properties are perceived to be more related than those not connected

closure (gestalt)

when an object or space is incomplete, people perceive the whole by filling in the missing information

grouping

the perceptual tendency to organize stimuli into coherent groups.

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.

convergence

binocular cue of depth perception based on signals from muscles that turn the eye to focus on near or approaching objects

visual cliff

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

binocular cues

depth cues, such as retinal disparity and eye convergence, 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 the two images, the closer the object.

monocular cues

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

relative height

distant objects are seen as smaller and higher in relation to objects that are closer.

relative size

perceptual clue to determine how close objects are to an object of known size. ex - when the moon is higher in the sky, you can't compare it to buildings or trees, so it appears smaller and far away.

interposition

visual signal that an object is closer than the ones behind it bc the closer object covers part of the farther object. ex - you know your keyboard is closer than your desk bc you see the desk around (behind) the keyboard.

linear perspective

two identical items will appear to vary in size with the amount of distance involved. also why roads appear to narrow in the distance.

light & shadow

a two dimensional image of the moon can appear to have three dimensional properties due to this on the moon's craters

relative motion

motion or speed of an object in respect of a particular point. a thrown ball may be going slower than a moving bus, but faster than a person walking.

size constancy

perception of size of objects are relative despite the fact that the size of objects on the retina vary greatly with distance

phi phenomenon

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

perceptual constancy

perceiving objects as unchanging (having consistent shapes, size, lightness, 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.

perceptual adaptation

in vision, the ability to adjust to an artificially displaced or even inverted visual field.

perceptual set

a mental predisposition to perceive one thing and not another.

extrasensory perception (ESP)

the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition.

parapsychology

the study of paranormal phenomena, including ESP and psychokinesis.

Learning

A relatively permanent change in an organism's behavior due to experience

Classical Conditioning (Pavlov and Watson)

we learn to associate two stimuli and thus to anticipate results

UCS - Unconditioned Stimulus

automatically and naturally triggers a response. reflexive, instinctive, unlearned behaviors

UCR - Unconditioned Response

Unlearned, naturally occurring response to an unconditioned stimulus (salivation when food is in the mouth)

Neutral Stimulus

CS - Conditioned Stimulus

Originally the neutral stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response

CR - Conditioned Response

Learned response to a previously neutral conditioned stimulus

Respondent Conditioning

Acquisition

The initial stage in Classical Conditioning
The phase associating a Neutral Stimulus (NS) with an Unconditioned Stimulus (UCS) so that the Neutral Stimulus (NS) comes to elicit a Conditioned Response (CR)
In Operant Conditioning, the strengthening of a reinforced response

Generalization

the tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses
Boy bitten by a neighbor's boxer & now runs away when he sees any dog

Discrimination

the learned ability to distinguish between a conditioned stimulus and stimuli that do not signal an unconditioned stimulus
Boy bitten by a neighbor's boxer, but still enjoys playing with his own golden retriever.

Extinction

The diminishing of a Conditioned Response
In Classical Conditioning this occurs when an Unconditioned Stimulus (UCS) no longer follows a Conditioned Stimulus (CS) - The bell is no longer followed by food
In operant conditioning, when a response is no longer reinforced

Spontaneous Recovery

The reappearance of an extinguished conditioned response after a rest period

Operant Conditioning (Skinner)

we learn to associate a response (our behavior) with a consequence. We repeat behaviors that result in good consequences and avoid those with bad ones.

Shaping

An operant conditioning technique that influences behavior by rewarding any act similar to the behavior and then requiring closer approximations to continue to receive the reward.

Successive Approximations

Reinforcement

Any event that strengthens, or increases, the behavior it follows (Not Reward)