psych unit 3 and 4

Sensation

Sensation

Detection of stimuli by sensory organs.

Perception

Interpretation of sensory information by the brain.

Absolute Threshold

The minimum stimulus intensity detected 50% of the time.

Difference Threshold

The smallest detectable difference between two stimuli.

Weber’s Law

The principle that the difference threshold is proportional to the stimulus intensity.

Fechner’s Law

Perceived intensity increases logarithmically with actual stimulus intensity.

Signal Detection Theory

Explains how stimuli are detected amidst background noise, considering both sensitivity and decision-making.

Adaptation

Decreased sensitivity to constant stimuli over time.

Habituation

Decreased response to repeated, non-threatening stimuli.

Perceptual Set

The predisposition to perceive stimuli in a certain way.

Selective Attention

Focusing on specific stimuli while ignoring others.

Parts of the Eye (Pathway of Light)

Light passes through the cornea, pupil, lens, and retina.

Rods

Photoreceptors in the retina sensitive to low light and peripheral vision.

Cones

Photoreceptors in the retina responsible for color vision and detail.

Visual Agnosia

Inability to recognize objects despite normal vision.

Trichromatic Theory

Color vision based on three types of cones sensitive to red, green, and blue.

Opponent Processing Theory

Color perception is controlled by opposing pairs (e.g., red-green, blue-yellow).

Subtractive vs. Additive Color Mixing

Subtractive mixing removes wavelengths; additive mixing adds them.

Phi Phenomenon

Perception of motion from sequential static images.

Figure-Ground Perception

The ability to distinguish an object from its background.

Gestalt Beliefs of Perception

The brain organizes patterns into a whole rather than individual parts.

Binocular Disparity and Depth Cues

The difference in images between two eyes provides depth perception.

Monocular Depth Cues

Depth cues available to one eye alone.

Visual Cliff

A test to assess depth perception in infants.

Perceptual Constancies (Shape, Color, Size)

Perception of objects as unchanging despite changes in sensory input.

Distal Stimulus

The actual object in the environment.

Proximal Stimulus

The image on the retina or sensory receptors.

Feature Analysis Theory

Perception is built from analyzing individual features.

Nearsightedness vs. Farsightedness

Vision conditions where the eye focuses light incorrectly, causing blurry vision.

Parts of the Ear (Pathway of Sound)

Sound travels through the outer ear, middle ear, and inner ear (cochlea) to be processed.

Perceptive Deafness

Hearing loss due to damage to the inner ear or auditory nerve.

Conductive Deafness

Hearing loss due to problems in the outer or middle ear.

Vestibular System

The system responsible for balance and spatial orientation.

Place Theory

Different frequencies stimulate different places on the basilar membrane.

Volley Theory

Groups of neurons fire in volleys to encode high-frequency sounds.

Frequency Theory

The frequency of nerve impulses corresponds to the frequency of a tone.

Cocktail Party Effect

The ability to focus on one voice among many in a noisy environment.

Dichotic Listening

A task in which different audio streams are presented to each ear.

Gustatory System

The sensory system responsible for taste.

Olfactory System

The sensory system responsible for smell.

Sensation of Touch

The perception of pressure, temperature, and pain via skin receptors.

Oleogustus

The taste of fat.

Gate Control Theory

The theory that pain signals are modulated by the spinal cord, which acts as a gate.

Kinesthetic System

The sensory system responsible for detecting body position and movement.

Synesthesia

A condition where stimulation of one sense leads to involuntary experiences in another sense.

Prosopagnosia

Inability to recognize faces despite normal vision.

Pheromones

Chemicals released by the body that affect the behavior of others of the same species.

Phantom Limb Sensation

The perception of sensations, including pain, in a limb that has been amputated.

Circadian Rhythm

The body's 24-hour internal clock that regulates cycles of sleep and wakefulness.

Alpha Waves

Slow brain waves that appear when a person is in a relaxed, awake state.

Beta Waves

Fast brain waves that occur during alert, focused states.

Stage 1 Sleep

The lightest sleep stage, where a person can easily be awakened; involves the transition from wakefulness to sleep.

Stage 2 Sleep

A deeper stage of sleep characterized by sleep spindles (bursts of brain activity) and K-complexes.

Stage 3 Sleep

Deep sleep marked by delta waves, often considered the most restorative sleep stage.

REM Sleep

Rapid eye movement sleep, where vivid dreaming occurs, and brain activity resembles wakefulness.

Activation-Synthesis Model

Theory suggesting that dreams result from the brain’s attempt to make sense of random neural activity during sleep.

Hypnagogic Sensations

Sensory experiences, like falling or floating, that occur as a person transitions to sleep.

Paradoxical Sleep

Another name for REM sleep, where the brain is active, but the body remains mostly paralyzed.

Restorative Theory of Sleep

Theory that sleep allows the body and brain to repair and rejuvenate.

REM Rebound

The increase in REM sleep after a period of REM sleep deprivation.

Microsleeps

Brief, unintended episodes of sleep, lasting a few seconds, that occur during wakefulness.

Insomnia

Difficulty falling asleep, staying asleep, or getting restful sleep.

Narcolepsy

A sleep disorder characterized by sudden and uncontrollable episodes of sleep during waking hours.

REM Sleep Behavior Disorder

A disorder where individuals physically act out dreams due to a lack of typical REM sleep paralysis.

Night Terrors

Episodes of intense fear, flailing, and screaming during sleep, typically occurring in children and in deep sleep.

Somnambulism (Sleepwalking)

Engaging in complex behaviors like walking while in a sleep state.

Sleep Apnea

A disorder characterized by repeated interruptions in breathing during sleep.

Age-Related Sleep Patterns

Changes in sleep architecture and duration that occur with age.

Psychoactive Drugs

Substances that alter mood, perception, and cognitive functions.

Narcotics

Drugs derived from opium that relieve pain and may produce euphoria; often addictive.

Sedatives

Drugs that depress the central nervous system and induce relaxation or sleep.

Stimulants

Drugs that increase central nervous system activity, leading to greater alertness and energy.

Suprachiasmatic Nucleus (SCN)

A part of the hypothalamus responsible for controlling circadian rhythms.

Pineal Gland

A small gland in the brain that produces melatonin, influencing sleep patterns.

Hallucinogens

Drugs that cause alterations in perception, thoughts, and feelings, often leading to hallucinations.

Melatonin

A hormone produced by the pineal gland that regulates sleep-wake cycles.