AP Psych Units 3-4

Sensation

The process by which sensory receptors receive and transmit stimulus energies from the environment to the brain.

Perception

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

Bottom-up processing

Analysis that begins with 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 experiences and expectations.

Selective attention

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

Inattentional blindness

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

Change blindness

Failing to notice changes in the environment, especially when those changes occur gradually.

Transduction

The conversion of one form of energy into another, such as transforming stimulus energies 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 stimulus intensity needed to detect a stimulus 50% of the time.

Signal detection theory

A theory predicting how and when we detect weak signals amid background noise, influenced by psychological factors like expectations and motivation.

Subliminal

Below one’s absolute threshold for conscious awareness, meaning the stimulus is detected without conscious perception.

Priming

The unconscious activation of certain associations, predisposing one’s perception, memory, or response.

Difference threshold

The minimum difference between two stimuli required for detection 50% of the time, also called the just noticeable difference (JND).

Weber’s law

The principle that, to be perceived as different, two stimuli must differ by a constant percentage rather than a constant amount.

Sensory adaptation

Diminished sensitivity to a constant or unchanging stimulus over time.

Perceptual set

A mental predisposition to perceive one thing and not another, influenced by experiences, expectations, and context.

Extrasensory perception (ESP)

The controversial claim that perception can occur without sensory input, including telepathy, clairvoyance, and precognition.

Parapsychology

The study of paranormal phenomena, including ESP and psychokinesis.

Wavelength

The distance between successive peaks of a wave, determining properties like color in light or pitch in sound.

Hue

The dimension of color determined by the wavelength of light (e.g., blue, green, red).

Intensity

The amount of energy in a light or sound wave, perceived as brightness or loudness, determined by wave amplitude.

Pupil

The adjustable opening in the center of the eye that controls the amount of light entering.

Iris

The colored muscle around the pupil that controls the amount of light entering the eye by adjusting the size of the pupil.

Lens

A transparent, flexible structure behind the pupil that changes shape to focus images on the retina.

Retina

The light-sensitive inner surface of the eye that contains receptor cells (rods and cones) and processes 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 and are essential for peripheral and night vision.

Cones

Retinal receptors concentrated in the fovea that detect color and fine detail in well-lit conditions.

Optic nerve

The nerve that carries visual information from the retina to the brain.

Blind spot

The point where the optic nerve leaves the eye, creating a gap in vision due to the absence of receptor cells.

Fovea

The central focal point in the retina where cones are highly concentrated, allowing for sharp central vision.

Feature detectors

Specialized neurons in the visual cortex that respond to specific aspects of a stimulus, such as edges, angles, and movement.

Parallel processing

The brain’s ability to process multiple aspects of a visual scene (such as color, motion, shape, and depth) simultaneously.

Young-Helmholtz trichromatic (three-color) theory

The theory that the retina contains three types of color receptors (red, green, and blue) that combine to create the perception of any color.

Opponent-process theory

The theory that color perception is controlled by opposing retinal processes (red-green, blue-yellow, and black-white), explaining afterimages and color vision at the neural level.

Gestalt

A psychological approach that emphasizes our tendency to integrate pieces of information into meaningful wholes.

Figure-ground

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

Grouping

The perceptual tendency to organize stimuli into coherent groups based on principles like proximity, similarity, continuity, and closure.

Retinal disparity

A binocular cue for depth perception that compares images from both eyes; the greater the disparity (difference), the closer the object appears.

Monocular cues

Depth cues that can be perceived using one eye, such as interposition, relative size, linear perspective, and texture gradient.

Phi phenomenon

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

Perceptual constancy

The ability to recognize objects as unchanging (having consistent shape, size, and color) despite changes in lighting, distance, or angle.

Color constancy

The ability to perceive consistent color in objects even when lighting changes alter the wavelengths reflected by them.

Depth perception

The ability to perceive the world in three dimensions and judge distance, allowing us to determine how far away objects are.

Visual cliff

A laboratory device used to test depth perception in infants and young animals, typically involving a glass-covered drop-off.

Binocular cues

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

Perceptual adaptation

The brain’s ability to adjust to changes in sensory input, such as adapting to a displaced or inverted visual field.

Audition

The sense or act of hearing.

Frequency

The number of complete wavelengths that pass a point in a given time, determining the pitch of a sound.

Pitch

A tone’s perceived highness or lowness, which depends on frequency.

Middle ear

The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that amplify sound vibrations.

Cochlea

A coiled, fluid-filled tube in the inner ear where sound waves are transformed into neural impulses by hair cells.

Inner ear

The innermost part of the ear containing the cochlea, semicircular canals, and vestibular sacs, which play roles in hearing and balance.

Sensorineural hearing loss

Hearing loss caused by damage to the cochlea’s hair cells or the auditory nerve, often due to aging or prolonged exposure to loud noise.

Conduction hearing loss

Hearing loss caused by damage to the mechanical structures of the ear that conduct sound waves to the cochlea.

Cochlear implant

A device that converts sound into electrical signals and stimulates the auditory nerve, providing hearing for those with sensorineural hearing loss.

Place theory

A theory of pitch perception that suggests different frequencies stimulate different locations along the cochlea’s basilar membrane, explaining high-pitched sounds.

Frequency theory

A theory of pitch perception that suggests the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, explaining low-pitched sounds.

Gate-control theory

The theory that the spinal cord contains a neurological "gate" that either blocks pain signals or allows them to pass to the brain, influenced by psychological and physiological factors.

Kinesthesia

The system for sensing the position and movement of individual body parts, enabling coordination.

Vestibular sense

The sense of body movement and balance, regulated by the inner ear’s semicircular canals and vestibular sacs.

Sensory interaction

The principle that one sense may influence another, such as the way smell affects taste.

Embodied cognition

The idea that bodily sensations, gestures, and movements can influence cognitive processes, including thoughts and emotions.

Gustav Fechner

A psychologist and physicist who founded psychophysics and studied the relationship between stimulus intensity and perception, developing the concept of absolute thresholds.

Ernst Weber

A psychologist known for Weber’s Law, which states that the just noticeable difference (JND) between two stimuli is proportional to the magnitude of the original stimulus.

David Hubel

A neuroscientist who, along with Torsten Wiesel, discovered feature detectors—specialized neurons in the visual cortex that respond to specific elements of stimuli such as edges, angles, and movement.

Torsten Wiesel

A neuroscientist who worked with David Hubel to study how the brain processes visual information and demonstrated the role of feature detectors in vision.

Learning

A relatively permanent change in behavior or knowledge due to experience.

Habituation

A decrease in response to a repeated stimulus over time.

Associative learning

Learning that certain events occur together; it can involve classical or operant conditioning.

Stimulus

Any event or situation that evokes a response.

Cognitive learning

The acquisition of mental information, whether by observing events, watching others, or through language.

Classical conditioning

A type of learning in which one learns to link two or more stimuli and anticipate events.

Behaviorism

The psychological perspective that focuses on observable behavior and dismisses mental processes as unscientific.

Neutral stimulus (NS)

In classical conditioning, a stimulus that initially elicits no response before conditioning.

Unconditioned response (UR)

An automatic, naturally occurring response to an unconditioned stimulus.

Unconditioned stimulus (US)

A stimulus that naturally and automatically triggers a response.

Conditioned response (CR)

A learned response to a previously neutral stimulus after conditioning.

Conditioned stimulus (CS)

A previously neutral stimulus that, after association with an unconditioned stimulus, triggers a conditioned response.

Acquisition

The initial stage of learning in classical conditioning, when a neutral stimulus is first associated with an unconditioned stimulus.

Higher-order conditioning

A process in which a conditioned stimulus is paired with a new neutral stimulus, creating a second conditioned stimulus.

Extinction

The diminishing of a conditioned response when the conditioned stimulus is repeatedly presented without the unconditioned stimulus.

Spontaneous recovery

The reappearance of an extinguished conditioned response after a pause.

Generalization

The tendency to respond similarly to stimuli that are similar to the conditioned stimulus.

Discrimination

The learned ability to distinguish between a conditioned stimulus and other irrelevant stimuli.

Operant conditioning

A type of learning in which behavior is strengthened if followed by reinforcement or diminished if followed by punishment.

Law of effect

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

Operant chamber (Skinner box)

A device used in operant conditioning research, containing a lever or key that an animal can manipulate to obtain reinforcement.

Reinforcement

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

Shaping

A process in operant conditioning in which reinforcers guide behavior toward closer and closer approximations of the desired behavior.

Discriminative stimulus

A stimulus that signals the presence of reinforcement, influencing a response.

Positive reinforcement

Increasing behaviors by presenting a positive stimulus after the behavior.

Negative reinforcement

Increasing behaviors by removing or reducing an aversive stimulus after the behavior.

Primary reinforcer

An innately reinforcing stimulus that satisfies a biological need.

Conditioned reinforcer (secondary reinforcer)

A stimulus that gains its reinforcing power through association with a primary reinforcer.

Reinforcement schedule

A pattern that defines how often a desired behavior will be reinforced.

Continuous reinforcement

Reinforcing the desired response every time it occurs, leading to rapid learning but also rapid extinction.

Partial (intermittent) reinforcement

Reinforcing a response only part of the time, leading to slower learning but greater resistance to extinction.

Fixed-ratio schedule

A reinforcement schedule that rewards a behavior after a set number of responses.