AP Psych 1.5-1.6

Consciousness

Our awareness of ourselves and our environment. It has varying levels (alert, drowsy, asleep, altered states); sleep and wakefulness are both states of consciousness.

Circadian Rhythm

The body's internal biological clock: regular bodily rhythms (sleep/wake cycle, body temperature, alertness) that follow a roughly 24-hour cycle. Strongly affected by light (light suppresses melatonin).

Jet Lag

Fatigue and grogginess caused by a disrupted circadian rhythm, e.g., flying across time zones so your body clock no longer matches local time. Shift work causes the same kind of disruption.

EEG Patterns

The distinct brain-wave patterns recorded by an electroencephalogram (EEG). Each sleep stage is identified by its own EEG pattern (beta → alpha → NREM-1, 2, 3 → REM).

Beta Waves

Fast, small brain waves of an awake, alert, actively thinking brain. (BAD: Beta = awake/alert)

Alpha Waves

Slower brain waves of a relaxed but still awake state, e.g., lying in bed with your eyes closed before falling asleep. (BAD: Alpha = relaxed)

Delta Waves

Large, slow brain waves of deep sleep (NREM-3). (BAD: Delta = deep sleep)

NREM Sleep

Non-rapid eye movement sleep: every sleep stage except REM (NREM-1, 2, 3). The body is less aroused. You cycle through all stages about every 90 minutes, and deep NREM-3 periods get shorter as the night goes on.

NREM-1

The lightest, transitional stage of sleep (only a few minutes). Breathing slows, brain waves become irregular, and hypnagogic sensations (falling, floating) can occur.

NREM-2

Clearly asleep but still fairly easy to wake. Marked by sleep spindles (bursts of rapid, rhythmic brain-wave activity). About 20 minutes per cycle; the stage we spend the most total time in.

NREM-3

Deep sleep marked by large, slow delta waves. Hardest stage to wake someone from; growth hormone is released here. Gets shorter toward morning. Sleepwalking happens in this stage.

Hallucinations

False sensory experiences, like seeing or hearing something with no external stimulus. Ex: hypnagogic hallucinations while drifting into NREM-1.

Hypnagogic Sensations

Bizarre, dreamlike sensory experiences that occur as you enter NREM-1, such as the feeling of falling or floating, or a sudden body jerk.

REM Sleep (Paradoxical Sleep)

Rapid eye movement sleep. Called paradoxical sleep because the brain is highly active (waves look like being awake) while the body's muscles are relaxed and nearly paralyzed. Vivid dreams happen here; REM periods get longer as the night goes on.

Dreaming

A sequence of images, emotions, and thoughts passing through a sleeping mind. Vivid dreams usually happen during REM, so you're more likely to remember a dream if woken during REM.

REM Rebound

The tendency for REM sleep to increase after a person has been deprived of REM sleep. Ex: after an all-nighter, you spend extra time in REM the next night.

Activation-Synthesis Theory (Dreams)

Dream theory: dreams are the brain's attempt to make sense of (synthesize) random neural activity (activation) that fires during REM sleep. Dreams are a byproduct of brain activity, not hidden messages.

Consolidation Theory (Dreams)

Dream theory: dreams help us sort, process, and file away the day's experiences and memories. (Also called the information-processing theory of dreams.)

Memory Consolidation Theory (Sleep)

Theory of WHY WE SLEEP: sleep strengthens and stores memories by moving them from the hippocampus into long-term storage in the cortex. Ex: sleeping after studying improves recall.

Restoration Theory (Sleep)

Theory of WHY WE SLEEP: sleep lets the body and brain repair and restore resources used up during the day (neurons repair, muscles and tissue repair, growth hormone is released).

Insomnia

Ongoing problems falling asleep or staying asleep. Sleeping pills and alcohol can make it worse because they reduce REM sleep.

Narcolepsy

Sleep disorder with uncontrollable sleep attacks in which the person may fall directly into REM sleep, often at dangerous times. Linked to a lack of orexin, a neurotransmitter for alertness.

REM Sleep Behavior Disorder

Sleep disorder in which the normal muscle paralysis of REM fails, so the person physically acts out their dreams (talking, kicking, punching). Can injure themselves or a bed partner.

Sleep Apnea

Sleep disorder in which breathing temporarily stops during sleep, followed by brief awakenings, often hundreds of times a night. The person gets little deep/REM sleep and is tired during the day; often linked to obesity and loud snoring.

Somnambulism

Sleepwalking: walking or doing other activities while asleep. Happens during NREM-3 (deep) sleep; most common in children, and most people outgrow it.

Sensation

The process by which sensory receptors detect stimulus energy from the environment and transduce it into neural messages. Raw data coming in.

Perception

The process by which the brain organizes and interprets sensory information to give it meaning. Ex: sensation = light hits your retina; perception = recognizing your friend's face.

Transduction

Converting one form of energy (light, sound waves, chemicals, pressure) into neural impulses the brain can interpret. Happens at the sensory receptors (rods/cones in the eye, hair cells in the ear).

Absolute Threshold

The minimum amount of stimulation needed to detect a stimulus at least 50% of the time. Ex: the faintest sound you can hear half the time.

Subliminal

Below the absolute threshold, so it isn't consciously noticed. Ex: an image flashed too fast to see. (The teacher's slides say this one isn't on the AP exam.)

Priming

The activation, often unconscious, of certain associations that affects later perception, memory, or response. Ex: seeing the word "yellow" makes you faster to recognize the word "banana."

Just-Noticeable Difference (Difference Threshold)

The smallest change in a stimulus that can be detected at least 50% of the time.

Weber's Law

To be noticed as different, two stimuli must differ by a constant minimum PERCENTAGE, not a constant amount. The bigger the original stimulus, the bigger the change needed. Ex: 2 oz is noticeable on 50 oz, but 100 oz needs 4 oz.

Sensory Adaptation

Reduced sensitivity to a stimulus after constant, unchanging exposure to it. Ex: you stop smelling the air freshener a few minutes after entering a room.

Sensory Interaction

The principle that the senses work together and one sense can influence another. Ex: smell affects taste, so food tastes bland when your nose is stuffed.

Synesthesia

A rare condition in which stimulating one sense triggers an experience in another. Ex: hearing music and seeing shapes or colors, or hearing a name and seeing green.

Retina

The light-sensitive (photosensitive) surface at the back of the eye. It contains the rods and cones (photoreceptors) and layers of neurons that start processing visual information.

Blind Spot

The point where the optic nerve leaves the eye. There are no rods or cones there, so it captures no image; the brain fills in the gap so we don't notice it.

Visual Nerve (Optic Nerve)

The nerve that CARRIES neural impulses from the eye to the brain (thalamus, then occipital lobe). It is made of the axons of ganglion cells. It does not transduce; transduction happens in the rods and cones.

Lens

The clear structure behind the pupil that changes shape to focus images onto the retina.

Accommodation

The process by which the lens changes shape (thicker for close objects, flatter for far objects) to focus images on the retina.

Nearsightedness

Close objects look clear but far objects look blurry, because light focuses IN FRONT of the retina. Caused by eye shape; both genetics and environment (like heavy screen time) play a role.

Farsightedness

Far objects look clear but close objects (like words in a book) look blurry, because light focuses BEHIND the retina (under-focused).

Rods

Photoreceptors in the periphery of the retina that detect black, white, and gray, shape, and movement, but NOT color. Used for peripheral and low-light (twilight) vision; key to dark adaptation.

Cones

Photoreceptors concentrated in the fovea (center of the retina) that detect color and fine detail and work best in bright light. Three types: blue (short), green (medium), and red (long wavelengths).

Photoreceptors

The light-sensitive cells of the retina (rods and cones) that transduce light into neural signals. Rods are spread through the periphery; cones are packed in the fovea.

Fovea

The central focal point of the retina, packed with cones and containing no rods. The spot of sharpest, most detailed color vision.

Cornea

The clear, protective outer layer at the front of the eye that bends incoming light to begin focusing it.

Pupil

The adjustable opening in the center of the eye that lets light in. Gets bigger (dilates) in dim light and smaller (constricts) in bright light.

Iris

The colored ring of muscle around the pupil that controls the pupil's size, controlling how much light enters the eye.

Trichromatic Theory (Young-Helmholtz)

Color vision theory: the retina has three types of cones (red, green, blue), and stimulating them in different combinations produces every color we see. Explains color vision at the cone level. Ex: zoom in on a TV screen and you see only red, green, and blue pixels.

Opponent-Process Theory

Color vision theory: color is processed in opposing pairs (red-green, blue-yellow, black-white). When one color in a pair is stimulated, the other is inhibited. Happens in the ganglion cells and explains afterimages.

Short Wavelengths

Light wavelengths detected by BLUE cones. (Rainbow ROYGBIV goes from long to short: red is longest, blue/violet shortest.)

Medium Wavelengths

Light wavelengths detected by GREEN cones.

Long Wavelengths

Light wavelengths detected by RED cones.

Afterimages

An image that stays after you stare at a color and then look away, showing up in the opponent color (stare at green, then see red). Caused by one side of an opponent-process pair getting fatigued. Evidence for opponent-process theory.

Ganglion Cells

Neurons in the retina that receive signals from the rods and cones; their axons bundle together to form the optic nerve. They perform opponent processing in pairs: red/green, blue/yellow, black/white. Path: rods/cones → ganglion cells → optic nerve → brain.

Dichromatism

A color vision deficiency in which only two types of cones work (usually red or green cones are missing or faulty), so certain colors can't be told apart, most often red vs. green. Ex: dogs are dichromatic.

Monochromatism

A rare color vision deficiency in which only one type of cone works or none do, so the person sees only shades of gray (total color blindness).

Prosopagnosia

"Face blindness": inability to recognize familiar faces even though the rest of vision is normal. Caused by damage to visual-processing areas of the brain.

Blindsight

Responding to visual information without consciously seeing it, usually after damage to the primary visual cortex (occipital lobe). Ex: a person who says they're blind still steps around an obstacle.

Wavelengths

The distance from the peak of one wave to the peak of the next. In vision, wavelength determines hue (color); in hearing, it determines pitch. Shorter wavelength = higher frequency.

Pitch

How high or low a tone sounds. Depends on frequency (sound waves per second, measured in hertz, Hz): shorter wavelength = higher frequency = higher pitch.

Amplitude

The height of a sound wave, which determines loudness. Measured in decibels (dB): 0 dB is the absolute threshold of hearing, normal conversation is about 60 dB, and long exposure above 85 dB can damage hearing.

Place Theory

Pitch theory: we hear different pitches because different frequencies stimulate different PLACES along the cochlea's basilar membrane. Best explains HIGH-pitched sounds.

Frequency Theory

Pitch theory: the rate of nerve impulses traveling up the auditory nerve matches the tone's frequency, which lets us sense its pitch. Best explains LOW-pitched sounds.

Volley Theory

Pitch theory: groups of neurons take turns firing, so their combined rate can match frequencies faster than any single neuron can fire. Explains mid-range pitches; extends frequency theory.

Sound Localization

How we figure out where a sound is coming from. The brain compares when the sound reaches each ear (it hits one ear first) and how loud it is in each ear.

Conduction Deafness

Less common hearing loss caused by damage to the mechanical system that carries sound waves to the cochlea (e.g., punctured eardrum, damaged middle-ear bones).

Sensorineural Deafness

More common hearing loss ("nerve deafness") caused by damage to the cochlea's hair cell receptors or to the auditory nerve. Usually from aging, heredity, or long exposure to loud noise.

Cochlear Implant

A device that converts sounds into electrical signals and stimulates the auditory nerve through electrodes in the cochlea. Used for sensorineural deafness.

Olfaction (Olfactory System)

The sense of smell. Odor molecules bind to receptors in the nose, and signals go to the olfactory bulb and then directly to memory and emotion areas. The ONLY sense not processed first by the thalamus, which is why smells trigger strong memories.

Thalamus

The brain's sensory relay station. It sends incoming sensory information (vision, hearing, taste, touch) to the right areas of the cortex. Smell is the only sense that skips it. (Also in the 1.4 deck.)

Pheromones

Chemical signals released by an animal and detected through the olfactory system by others of the same species, affecting their behavior.

Gustation

The sense of taste. Chemical receptor cells (taste buds) on the tongue detect the basic tastes: sweet, sour, salty, bitter, umami, and oleogustus.

Umami

The savory, meaty, "brothy" taste, triggered by glutamate (e.g., soy sauce, parmesan, broth, MSG).

Oleogustus

The taste of fat, a proposed sixth basic taste.

Taste Receptors

Receptor cells in the taste buds of the tongue and mouth that transduce chemicals in food into neural signals. How many you have determines how sensitive you are to tastes.

Supertasters

People with more taste receptors than average, who taste flavors more intensely. Especially sensitive to bitter foods (broccoli, spinach, coffee, dark chocolate).

Medium Tasters

People with an average number of taste receptors (about half of people). They can taste bitterness but don't strongly dislike it.

Nontasters

People with fewer taste receptors who taste flavors less intensely and can't detect certain bitter compounds (about 25% of people).

Sensation of "Hot"

Produced when the warm receptors and cold receptors in the skin are stimulated at the same time. (The skin's touch receptors detect pressure, warmth, cold, and pain.)

Pain

The body's warning system, processed in both the body (nerves, spinal cord) and the brain. Shaped by biological, psychological (attention, expectations), and social-cultural factors. Reduced by endorphins (biological) and distraction (psychological).

Gate Control Theory

Pain theory: the spinal cord has a neurological "gate" that either blocks pain signals or lets them through to the brain. Small nerve fibers open the gate (pain is felt); large-fiber activity (rubbing, massage) or signals from the brain (distraction) close it. Ex: rubbing a stubbed toe makes it hurt less.

Phantom Limb Sensation

When people who have lost a limb still feel sensation or pain where the limb used to be. With no real sensory input, the brain misreads its own CNS activity as coming from the missing limb.

Vestibular Sense

The sense of balance and of your head and body's position and movement in space. Detected mainly by the semicircular canals in the inner ear, with signals sent to the cerebellum. Ex: feeling dizzy after spinning.

Semicircular Canals

Three fluid-filled, ring-shaped canals in the inner ear. The fluid moves when your head turns or tilts, sending balance information to the brain (cerebellum).

Kinesthesis

The sense of the position and movement of your own body parts, using sensors in the muscles, tendons, and joints. Ex: touching your nose with your eyes closed. (Balance from the inner ear is the vestibular sense, not kinesthesis.)