Psychology: Consciousness and Sleep

Definition: Awareness of external stimuli, internal sensations, and personal thoughts. Application: Being aware that you are sitting in class, hearing your teacher, and thinking about an upcoming test.

Definition: The body's internal 24-hour clock that regulates sleep, alertness, temperature, and other bodily functions. Application: Feeling sleepy at night and naturally becoming more alert in the morning.

Definition: Brain waves associated with relaxed wakefulness or drowsiness (8–12 Hz). Application: Your brain produces alpha waves when you close your eyes and relax.

Definition: High-frequency brain waves associated with alertness and focused attention (13–24 Hz). Application: Your brain produces beta waves while actively solving a difficult math problem.

Definition: The lightest stage of sleep, characterized by theta waves, hypnagogic sensations, and hypnic jerks. Application: Just as you begin falling asleep, you suddenly feel like you're falling and jerk awake.

Definition: A stage of sleep characterized by theta waves and sleep spindles. Application: Your brain produces sleep spindles while you are asleep, helping distinguish this stage from Stage 1.

Definition: Deep, slow-wave sleep characterized by delta waves; sleepwalking, bedwetting, and night terrors can occur. Application: A person who sleepwalks during the night is likely experiencing Stage 3 sleep.

Definition: A stage associated with vivid dreams, rapid eye movements, and brain activity similar to wakefulness. Application: You experience a vivid, story-like dream while your body remains mostly immobile.

Definition: The theory that dreams occur when the brain combines random brainstem activity during REM sleep into a meaningful story. Application: Your brain turns random neural activity into a dream about being chased through your school.

Definition: Dream-like sensations that occur as a person transitions into Stage 1 sleep. Application: You hear what sounds like someone calling your name just as you are falling asleep.

Definition: Another name for REM sleep because brain activity resembles wakefulness while muscle activity is greatly reduced. Application: Your brain is highly active during a vivid dream, but your body remains mostly still.

Definition: The theory that sleep allows the body and brain to replenish energy and restore bodily resources. Application: After a long day, sleeping helps your body recover and prepares you for the next day.

Definition: The idea that sleep helps organize and strengthen newly learned information into long-term memories. Application: After studying for a test, getting a good night's sleep helps you remember the material the next day.

Definition: The tendency to experience increased REM sleep after being deprived of REM sleep. Application: After several nights of insufficient REM sleep, you experience longer periods of REM sleep when you finally get enough rest.

Definition: Brief, involuntary episodes of sleep that occur while someone appears to be awake. Application: A sleep-deprived student briefly loses awareness during a lecture without realizing it.

Definition: A sleep disorder involving difficulty falling asleep, staying asleep, or getting sufficient restful sleep. Application: A person regularly struggles to fall asleep despite feeling tired.

Definition: A sleep disorder characterized by excessive daytime sleepiness and sudden episodes of falling asleep. Application: A person unexpectedly falls asleep during a conversation despite having slept the previous night.

Definition: A disorder in which the normal muscle paralysis during REM sleep is absent, allowing people to physically act out their dreams. Application: A person moves their arms and legs while acting out a dream during REM sleep.

Definition: A sleep disorder involving walking or performing other behaviors while asleep, usually during Stage 3 sleep. Application: A person gets out of bed and walks around the house without being consciously aware.

Definition: A disorder in which breathing repeatedly stops and starts during sleep, disrupting restful sleep. Application: A person repeatedly pauses breathing during the night and wakes up feeling tired.

Definition: Chemicals that alter perception, mood, and behavior by affecting the nervous system. Application: A substance that changes someone's alertness, mood, or perception is considered psychoactive.

Definition: Drugs that increase neural activity and speed up bodily functions. Caffeine increases alertness, while cocaine can produce euphoria and increased energy. Application: Caffeine can make someone feel more awake, while cocaine is associated with serious cardiovascular risks.

Definition: Drugs that reduce neural activity, slow bodily functions, and impair memory and judgment. Application: Alcohol can slow reaction time and impair someone's ability to make decisions.

Definition: The brain's biological clock that receives light information from the retina and helps regulate circadian rhythms. Application: Sunlight entering your eyes helps your SCN regulate your sleep-wake cycle.

Definition: A gland that secretes melatonin, helping regulate the sleep-wake cycle. Application: As it gets darker at night, the pineal gland releases melatonin to help prepare your body for sleep.

Definition: A hormone released by the pineal gland that helps regulate the sleep-wake cycle. Application: Melatonin levels typically rise in the evening, signaling to your body that it is time to sleep.

Definition: Drugs that distort perceptions and can produce sensory experiences without corresponding external stimuli. Marijuana is classified as a mild hallucinogen in the slides. Application: Marijuana can distort someone's perception of time and alter sensory experiences.

Definition: Drugs that relieve pain and can produce euphoria by acting on opioid receptors; they carry a high risk of dependence and addiction. Application: Opioids can reduce the perception of pain but also slow physiological responses.

Definition: A reduced response to a substance's usual dosage, potentially leading to the need for larger amounts to produce the same effect. Application: A person develops tolerance when the same amount of a substance produces less of an effect than it previously did.

Definition: Persistent cravings and continued substance use or behavior despite known negative consequences. Application: Someone continues a harmful behavior despite knowing it is damaging their relationships and school performance.

Superordinate category: Basic principles of sensation and perception. Definition: The physical stimulation of sensory receptor cells that detect information from the environment. Application: When you hear a dog barking, your ears detect the sound waves. That detection is sensation.\

Superordinate category: Basic principles of sensation and perception. Definition: The process of selecting, organizing, and interpreting sensory information to understand the world. Application: When you hear barking and recognize that it is your neighbor's dog, your brain is using perception to interpret the sound.\

Superordinate category: Sensation and perception research. Definition: The study of the relationship between physical stimuli and the psychological experiences they produce. Established by Gustav Fechner. Application: A researcher tests how much louder a sound must become before people notice a difference. This is an example of psychophysics.\

Superordinate category: Sensory thresholds. Definition: The minimum intensity of a stimulus that a person can detect 50% of the time. Application: You slowly add lemon juice to a glass of water until you can just barely taste it. The minimum detectable amount represents your absolute threshold.\

Superordinate category: Sensory thresholds. Definition: The minimum difference between two stimuli that a person can detect 50% of the time; also called the just noticeable difference (JND). Application: You increase the volume of your headphones one level at a time until you can just barely tell the sound has changed. That change represents your difference threshold.\

Superordinate category: Sensory thresholds and psychophysical laws. Definition: The just noticeable difference between stimuli is a constant proportion of the original stimulus, with the proportion varying across senses. Application: If you can barely notice a 2-pound increase on a 100-pound weight, you would generally need a larger increase on a 200-pound weight to notice the same proportional difference. This demonstrates Weber's law.\

Superordinate category: Sensory thresholds and psychophysical laws. Definition: The relationship between physical stimulus intensity and perceived intensity is logarithmic, meaning equal increases in physical energy produce progressively smaller increases in perceived intensity. Application: Increasing a room's lighting from very dim to moderately bright may feel like a major change, while adding the same amount of light to an already bright room may feel less noticeable. This illustrates Fechner's law.\

Superordinate category: Visual perception disorders. Definition: A condition, also called face blindness, in which a person has difficulty recognizing familiar faces despite being able to see them. Application: A student sees their teacher at the grocery store but cannot recognize their face until the teacher speaks. This is an example of prosopagnosia.\

Superordinate category: Sensory detection. Definition: The theory that detecting a stimulus depends on both its intensity and psychological factors such as attention, expectations, motivation, and alertness. Application: A student who is eagerly waiting for a text message notices their phone vibrating immediately, while a distracted student misses the same vibration. This illustrates signal detection theory.\

Superordinate category: Sensory processes. Definition: A decrease in sensitivity to a constant, unchanging stimulus over time. Application: When you first put on a watch, you notice it against your wrist, but after a while, you barely feel it. This is sensory adaptation.\

Superordinate category: Learning and sensory responsiveness. Definition: A decrease in responsiveness to a repeated stimulus because it becomes familiar. Application: After living near a railway for several days, you stop consciously noticing the train passing each night. This is habituation.\

Superordinate category: Factors influencing perception. Definition: A mental predisposition or readiness to perceive a stimulus in a particular way because of prior experiences or expectations. Application: After watching a scary movie, you mistake a coat hanging in the dark for a person. Your expectations influence your interpretation through perceptual set.\

Superordinate category: Attention and perception. Definition: Focusing conscious awareness on one particular stimulus while ignoring other stimuli. Application: At a loud party, you concentrate on your friend's conversation and tune out most of the surrounding noise. This demonstrates selective attention, also illustrated by the cocktail party effect.\

Superordinate category: Vision and sensory transduction. Definition: Light passes through the cornea → pupil → lens → retina. The iris controls pupil size, the lens focuses light onto the retina, and retinal photoreceptors convert light into neural signals that travel through the optic nerve toward the brain. Application: When you read a book, light reflected from the page enters through your cornea and pupil, is focused by your lens onto your retina, and is converted into neural signals that your brain processes into the words you see.\

Superordinate category: Visual photoreceptors. Definition: Retinal receptor cells specialized for vision in dim light; they do not detect color and are important for peripheral vision. Application: When you walk into a dark room, rods help you make out furniture even though you cannot distinguish its colors clearly.\

Superordinate category: Vision and refractive errors. Definition: A vision condition in which nearby objects appear clear but distant objects appear blurry because light focuses in front of the retina. It is commonly corrected with a concave (diverging) lens. Application: A student can read a textbook clearly but cannot read the classroom whiteboard from the back of the room. This is nearsightedness.\

Superordinate category: Vision and refractive errors. Definition: A vision condition in which nearby objects may appear blurry because light tends to focus behind the retina. It is commonly corrected with a convex (converging) lens. Application: Someone struggles to read small print on a page up close but sees distant objects more clearly. This may indicate farsightedness.\

Superordinate category: Visual photoreceptors. Definition: Retinal receptor cells responsible for color vision and fine visual detail; they function best in bright light and are concentrated in the fovea. Application: In daylight, cones help you distinguish a red apple from a green apple and read the tiny text on its label.\

Superordinate category: Theories of color vision. Definition: The theory that color vision begins with three types of cones sensitive to different ranges of wavelengths, commonly associated with red, green, and blue. Application: When you look at a purple flower, your three cone types respond in different proportions, and your brain combines their signals to produce the perception of purple.\

Superordinate category: Theories of color vision. Definition: The theory that color vision involves opposing neural channels: red versus green, blue versus yellow, and black versus white. It helps explain color afterimages. Application: After staring at a green image and then looking at a white wall, you may see a reddish afterimage. This occurs because of opposing color-processing mechanisms.\

Superordinate category: Vision and focusing. Definition: The process in which the eye's lens changes shape to focus light from objects at different distances onto the retina. Application: When you shift your gaze from a distant classroom clock to a textbook held close to your face, your lens changes shape to keep the text in focus. This is accommodation.\

Superordinate category: Color perception and light. Definition: Additive mixing combines colored lights; red, green, and blue light together can produce white. Subtractive mixing combines pigments or inks that absorb wavelengths; cyan, magenta, and yellow are the traditional primary colors used in this model. Application: A phone screen creates colors by combining red, green, and blue light through additive mixing, while mixing paints uses subtractive mixing because pigments absorb certain wavelengths.\

Superordinate category: Visual perception and apparent motion. Definition: The illusion of movement created when stationary lights flash on and off in succession. Application: A row of lights on a theater sign turns on one bulb after another, making it appear that a light is traveling around the sign. This is the phi phenomenon.\

Superordinate category: Gestalt principles of perception. Definition: The tendency to organize a visual scene by separating the main object of attention (figure) from its surrounding background (ground). Application: When reading black text on a white page, you perceive the letters as the figure and the white page as the ground.\

Superordinate category: Perceptual organization. Definition: Principles explaining how the brain organizes individual sensory elements into meaningful, unified wholes. Gestalt psychology emphasizes that the whole is greater than the sum of its parts. Application: When you see several separate dots arranged in the outline of a circle, your brain groups them together and perceives a complete shape. This illustrates Gestalt perception, especially the principle of closure.\

Superordinate category: Depth perception. Definition: Differences between images in each eye help the brain judge distance. Application: Your brain compares both eye images to judge how far away a ball is.\

Superordinate category: Depth perception. Definition: Depth cues that require only one eye, such as relative size and linear perspective. Application: A distant building looks smaller than a nearby one.\

Superordinate category: Depth perception. Definition: An experiment testing whether infants and animals perceive depth using an apparent drop-off. Application: An infant hesitates to crawl over a glass surface that looks like a cliff.\

Superordinate category: Perceptual organization. Definition: Perceiving objects as stable despite changes in distance, angle, or lighting. Application: A car looks the same size even as it drives farther away.\

Superordinate category: Sensation and perception. Definition: The actual object or event in the environment. Application: The actual tree you are looking at is the distal stimulus.\

Superordinate category: Sensation and perception. Definition: The pattern of sensory energy reaching your receptors. Application: The image of the tree projected onto your retina is the proximal stimulus.\

Superordinate category: Visual perception. Definition: The brain identifies objects by detecting and combining individual features. Application: You recognize a letter by its lines and curves.\

Superordinate category: Audition. Definition: Sound travels through the pinna and ear canal, vibrates the eardrum and ossicles, and reaches the cochlea, where hair cells transduce it into neural signals. Application: Sound waves make your eardrum vibrate before signals travel to your brain.\

Superordinate category: Hearing disorders. Definition: Hearing loss caused by damage to cochlear hair cells or auditory nerves. Application: Damaged cochlear hair cells make sounds difficult to hear.\

Superordinate category: Hearing disorders. Definition: Hearing loss caused by problems transmitting sound through the outer or middle ear. Application: Damaged ossicles prevent sound vibrations from reaching the cochlea properly.\

Superordinate category: Body senses. Definition: The sensory system responsible for balance, head position, and spatial orientation. Application: Your vestibular system helps you stay balanced while spinning.\

Superordinate category: Pitch perception. Definition: Pitch depends on where the basilar membrane is stimulated; it best explains high pitches. Application: High-frequency sounds activate specific areas of the basilar membrane.\

Superordinate category: Pitch perception. Definition: Groups of neurons alternate firing to encode pitches too high for one neuron to match alone. Application: Neurons take turns firing to represent a higher sound frequency.\

Superordinate category: Pitch perception. Definition: Pitch is determined by the rate of neural impulses; it best explains low pitches. Application: A low-pitched sound produces a slower pattern of neural firing.\

Superordinate category: Selective attention. Definition: Focusing on one conversation while filtering out other sounds. Application: You hear your name across a noisy cafeteria.\

Superordinate category: Auditory attention. Definition: Listening to different messages presented to each ear simultaneously. Application: You hear one story in your left ear and another in your right.\

Superordinate category: Chemical senses. Definition: The taste system detects sweet, sour, salty, bitter, umami (savory), and oleogustus (fat). Application: Taste receptors detect sweetness when you eat candy.\

Superordinate category: Chemical senses. Definition: The smell system detects airborne chemicals through receptors in the nasal cavity. Smell bypasses the thalamus initially. Application: Smelling fresh cookies activates your olfactory receptors.\

Superordinate category: Chemical communication. Definition: Chemicals released by organisms that can influence other members of the same species. Application: Certain insects release pheromones to attract potential mates.\

Superordinate category: Somatosensation. Definition: Sensory receptors detect pressure, temperature, and pain. Application: Receptors in your skin detect a cold glass.\

Superordinate category: Pain perception. Definition: The spinal cord can regulate pain signals traveling to the brain. Application: Rubbing your elbow after bumping it may reduce the pain you feel.\

Superordinate category: Body senses. Definition: Receptors in muscles and joints provide information about body position and movement. Application: You can touch your nose with your eyes closed.\

Superordinate category: Sensory perception. Definition: Stimulation of one sensory pathway automatically triggers an experience in another. Application: Someone consistently perceives the number 5 as red.\

Superordinate category: Vision. Definition: Retinal cells that detect light; rods support dim-light vision, while cones detect color and detail. Application: Cones help you identify colors in daylight.\

Superordinate category: Visual perception. Definition: The illusion that stationary objects are moving when presented in sequence. Application: Successive images in an animation appear to move.