Ap Psychology Unit 1b (Sleep, Sensation, & Perception)

Sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Sensory receptors

sensory nerve endings that respond to stimuli.

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.

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.

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 stimulus energy 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 faint stimulus amid background stimulation.

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 percent 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 adaptation

diminished sensitivity as a consequence of constant stimulation.

perceptual set

a mental predisposition to perceive one thing and not another.

wavelength

the distance from the peak of one light or sound wave to the peak of the next.

Hue

the dimension of color that is determined by the wavelength of light.

intensity

the amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness.

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 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 sensitive to movement; necessary for peripheral and twilight vision, when cones don't respond.

cones

retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions.

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.

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 types of 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.

parallel processing

processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision.

feature detectors

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

figure ground

the organization of the visual field into objects that stand out from their surroundings.

gestalt

an organized whole.

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.

grouping

the perceptual tendency to organize stimuli into coherent groups.

binocular cue

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

visual cliff

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

monocular cue

a depth cue, such as interposition or linear perspective, available to either eye alone.

retinal disparity

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

perceptual constancy

perceiving objects as unchanging (having consistent color, brightness, shape, and size) even as illumination and retinal images change.

perceptual adaptation

the ability to adjust to changed sensory input, including 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 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.

cochlea

a coiled, bony, fluid-filled tube in the inner ear.

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; the most common form of hearing loss, also called nerve deafness.

conduction hearing loss

a less common form of 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 nerve matches 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.

hypnosis

a social interaction in which one person suggests to another that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur.

dissociation

a split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others.

olfaction

the sense of smell.

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.

embodied cognition

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

sensory interaction

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

REM sleep behavior disorder

normal REM paralysis does not occur; instead, twitching, walking, talking, kicking, punching, and even acting out one's dream can occur

Consciousness

the state of being aware of and able to think about one's own existence, thoughts, and surroundings.

Cognitive neuroscience

the study of the brain's role in mental processes, integrating psychology and neuroscience to understand how brain activity influences cognition.

Selective attention

the process of focusing on a particular object or task while ignoring others, allowing for more efficient information processing.

Inattentional blindness

the failure to notice a fully visible but unexpected object because attention is engaged elsewhere.

Change blindness

the phenomenon where significant changes in a visual scene go unnoticed due to disruptions in visual attention.

Dual processing

the principle that information is processed simultaneously in two different ways: consciously (explicit) and unconsciously (implicit).

Blindsight

a condition where individuals with damage to their primary visual cortex can still respond to visual stimuli without consciously perceiving them.

Sequential processing

the cognitive process of handling information one step at a time, as opposed to processing multiple pieces of information simultaneously.

Sleep

a natural, recurring state of rest characterized by reduced consciousness, muscle relaxation, and decreased sensory activity, crucial for physical and mental restoration.

Circadian rhythm

the internal biological clock that regulates the sleep-wake cycle and other physiological processes on a roughly 24-hour cycle.

REM sleep

a sleep stage characterized by rapid eye movement, vivid dreams, and increased brain activity, essential for cognitive functions such as memory consolidation.

Alpha waves

brain wave patterns associated with relaxed, calm, and wakeful states, typically observed when one is at rest with eyes closed.

Delta waves

slow brain waves associated with deep, restorative sleep, crucial for physical recovery and memory consolidation.

Hallucinations

perceptions of objects or events that are not present in the external environment, often occurring in states of altered consciousness or psychological conditions.

Suprachiasmatic nucleus

a group of neurons in the hypothalamus that regulates the circadian rhythms and sleep-wake cycle.

Insomnia

a sleep disorder characterized by difficulty falling asleep, staying asleep, or waking up too early, leading to impaired functioning during the day.

Narcolepsy

a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden, uncontrollable episodes of sleep.

Sleep apnea

a sleep disorder where breathing repeatedly stops and starts during sleep, leading to poor sleep quality and potential health issues.

Night terrors

intense episodes of fear and panic during sleep, often accompanied by screaming, confusion, and rapid heart rate, typically occurring in non-REM sleep.

Dream

a sequence of thoughts, images, or emotions occurring during sleep, often reflecting the subconscious mind and influencing emotional well-being.

Manifest content

the actual storyline or imagery of a dream as remembered by the dreamer.

Latent content

the underlying meaning or symbolic significance of a dream, as interpreted by psychoanalytic theory.

REM rebound

an increase in REM sleep following a period of sleep deprivation or interruption, reflecting the body's attempt to restore lost REM sleep.

Psychoactive drug

a chemical substance that alters brain function, affecting mood, perception, consciousness, or behavior.

Substance disorder

a condition characterized by a compulsive pattern of substance use that leads to significant impairment or distress, including tolerance, withdrawal, and inability to control use.