Sensory&Perception/Learning

sensation

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 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

falling to see visible objects when our attention is directed elsewhere.

change blindness

falling 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

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

signal detection theory

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

subliminal

below one's absolute threshold for conscious awareness

priming

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

difference threshold

the minimum difference between two stimuli required for detection 50 of the time. We experience this as a just noticeable difference (or jnd).

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 adaptation

diminished sensitivity as a consequence of constant stimulation.

perceptual set

a mental predisposition to perceive one thing and not another

ESP

extrasensory perception

extrasensory perception

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

wavelength

the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths 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 of loudness, as determined yo 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.

retina

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

accommodation

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 cells 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, creating a "blind" spot because no receptor cells are located there.

fovea

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

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. This contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.

Young-Helmholtz trichromatic (thee-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 ex., some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.

gestalt

an organized whole, psychologists labeled as this emphasized our tendency to integrate pieces of information and meaningful wholes.

figure-ground

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

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.

visual cliff

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

binocular cues

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

retinal disparity

a binocular cue for perceiving depth: By comparing images from the retinal in the two eyes, the brain computes distance - the greater the disparity (difference) between the two images, the closer the objects.

monocular clues

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

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, 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.

perceptual adaptation

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

audition

the sense or act of hearing

frequency

the number of complete wavelengths that pass a point in a given time (for ex., 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.

cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear 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.

cochlear implant

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

place theory

in hearing, the theory that relates 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 sits 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 movement 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.

embodied cognition

in psychological science, the influence of bodily sensations, gestures, and other states on cognitive preferences and judgments.

learning

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

associative learning

Learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning).

classical conditioning

A type of learning in which an organism comes to associate stimuli. A neural stimulus that signals an unconditioned stimulus (UCS) begins to produce a response that anticipates and prepares for the unconditioned stimulus. Also called Pavlovian conditioning.

behaviorism

The view that psychology (1) should be an objective science that (2) studies behavior without reference to mental processes. Most research psychologists today agree with (1) but not with (2).

unconditioned response (UCR)

In classical conditioning, the unlearned, naturally occurring response to the unconditioned stimulus (UCS), such as salivation when food is in the mouth.

unconditioned stimulus (UCS)

In classical conditioning, a stimulus that unconditionally—naturally and automatically—triggers a response.

conditioned response (CR)

In classical conditioning, the learned response to a previously neutral conditioned stimulus (CS).

conditioned stimulus (CS)

In classical conditioning, an originally irrelevant stimulus that, after association with an unconditioned stimulus (UCS), comes to trigger a conditioned response.

acquisition

The initial stage in classical conditioning; the phase associating a neutral stimulus with an unconditioned stimulus so that the neutral stimulus comes to elicit a conditioned response. In operant conditioning, the strengthening of a reinforced response.

extinction

The diminishing of a conditioned response; occurs in classical conditioning when an unconditioned stimulus (UCS) does not follow a conditioned stimulus (CS); occurs in operant conditioning when a response is no longer reinforced.

spontaneous recovery

The reappearance, after a rest period, of an extinguished conditioned response.

generalization

The tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses.

discrimination

In classical conditioning, the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus.

operant conditioning

A type of learning in which behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher.

respondent behavior

Behavior that occurs as an automatic response to some stimulus; Skinner's term for behavior learned through classical conditioning.

operant behavior

Behavior that operates on the environment, producing consequences.

law of effect

Thorndike's principle that behaviors followed by favorable consequences become more likely, and that behaviors followed by unfavorable consequences become less likely.

operant chamber (Skinner box)

A chamber containing a bar or key that an animal can manipulate to obtain a food or water reinforce, with attached devices to record the animal's rate of bar pressing or key pecking. Used in operant conditioning research.

shaping

An operant conditioning procedure in which reinforcers guide behavior toward closer and closer approximations of a desired goal.

reinforcer

In operant conditioning, any event that strengthens the behavior it follows.

primary reinforcer

An innately reinforcing stimulus, such as one that satisfies a biological need.

conditioned reinforcer

A stimulus that gains its reinforcing power through its association with a primary reinforcer; also known as secondary reinforcer.

continuous reinforcement

Reinforcing the desired response every time it occurs.

partial (intermittent) reinforcement

Reinforcing a response only part of the time; results in slower acquisition of a response but much greater resistance to extinction than does continuous reinforcement.

fixed-ratio schedule

In operant conditioning, a schedule of reinforcement that reinforces a response only after a specified number of responses.

variable-ratio schedule

In operant conditioning, a schedule of reinforcement that reinforces a response after an unpredictable number of responses.

fixed-interval schedule

In operant conditioning, a schedule of reinforcement that reinforces a response only after a specified time has elapsed.

variable-interval schedule

In operant conditioning, a schedule of reinforcement that reinforces a response at unpredictable time intervals.

punishment

An event that decreases the behavior that it follows.

cognitive map

A mental representation of the layout of one's environment. For example, after exploring a maze, rats act as if they have learned a cognitive map of it.

latent learning

Learning that occurs but is not apparent until there is an incentive to demonstrate it.

overjustification effect

The effect of promising a reward for doing what one already likes to do. The person may now see the reward, rather than intrinsic interest, as the motivation for performing the task.

intrinsic motivation

A desire to perform a behavior for its own sake and to be effective.

extrinsic motivation

A desire to perform a behavior due to promised rewards or threats of punishment.

observational learning

Learning by observing others.

modeling

The process of observing and imitating a specific behavior.

mirror neurons

Frontal lobe neurons that fire when performing certain actions or when observing another doing so. The brain's mirroring of another's action may enable imitation, language learning, and empathy.