psyc

Sensation

The process that occurs when special neuron receptor sites in the sense organs are activated, allowing outside stimuli to become neural signals in the brain.

Perception

The methods by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion.

Transduction

The process of converting outside stimuli into neural activity.

Just a noticeable difference (jnd)

The smallest difference between two stimuli that is detectable 50 percent of the time.

Absolute Threshold

The lowest level of stimulation that a person can consciously detect 50 percent of the time.

Subliminal Stimulation

Receiving messages below your absolute threshold for conscious awareness.

Sensory Adaptation

The tendency of sensory receptor cells to become less responsive to an unchanging stimulus.

Color (hue)

Length of waves seen after they hit objects and bounce back to us at different frequencies.

Saturation

Purity of the color perceived; a highly saturated color contains only its respective wavelengths.

Brightness

Amplitude of the wave; the higher the wave, the brighter the color.

Cornea

The clear outer covering of the eye that protects it and is involved in light entry.

Pupil

The black circle in the middle of the eye that changes size to control the amount of light entering.

Iris

The colored circular muscle that controls the size of the pupil.

Lens

The transparent structure that focuses light on the retina.

Retina

The back of the eye which contains the photoreceptors for light.

Rods

Visual receptors most sensitive to low levels of light, primarily responsible for night vision.

Cones

Visual receptors that respond during daylight and are responsible for color vision.

Fovea

The central area of the retina with the greatest density of photoreceptors.

Blind Spot

The portion of the retina where the optic nerve exits and where no light receptors exist.

Optic Nerve

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

Visual Accommodation

The adjustment of the lens thickness to focus on objects at varying distances.

Presbyopia

Age-related inability to focus on close objects due to a hardening lens.

Myopia

Nearsightedness; focal point falls short of the retina.

Hyperopia

Farsightedness; the focal point falls behind the retina.

Visual Acuity

The sharpness or keenness of vision, usually assessed with a Snellen chart.

Trichromatic Theory

The theory of color vision proposing three types of cones: red, blue, and green.

Opponent-Process Theory

The theory that proposes visual neurons are stimulated by light of one color and inhibited by another color.

Afterimage

The image that remains after the initial stimulation of the retina has ceased.

Color Blindness

Inability to perceive certain colors, most commonly red or green.

Pitch

How high or low a sound is, determined by the frequency of sound waves.

Volume

The loudness of a sound, measured in decibels.

Pinna

The outer ear that funnels sound waves into the auditory canal.

Cochlea

The snail-shaped structure in the inner ear filled with fluid that plays a crucial role in hearing.

Place Theory

Theory that different pitches are experienced based on stimulation of hair cells in different locations.

Frequency Theory

Theory that pitch is related to the speed of vibrations in the basilar membrane.

Conductive Hearing Impairment

Hearing loss caused by damage to the middle ear affecting sound wave transmission.

Nerve Hearing Impairment

Deafness resulting from damage to the inner ear preventing perception of certain frequencies.

Gustation

The sense of taste, relying on chemical receptors in the taste buds.

Taste Buds

Taste receptor cells that identify different flavors based on chemical molecules.

5 Basic Taste Types

Salt, sweet, sour, bitter, and umami.

Olfaction

The sense of smell, dependent on the ability to detect chemical substances.

Pheromones

Odor chemicals that communicate information, often related to sexual interest.

Gate-Control Theory

The theory that pain signals are modulated by a "gate" mechanism affecting how pain is perceived.

Kinesthetic Sense

The awareness of body positions and movement in relation to each other.

Vestibular Sense

The sense related to balance and spatial orientation, located in the inner ear.

Constancy

The tendency to perceive objects as unchanging despite changes in sensory input.

Gestalt Principles

Perception laws that describe how we organize visual elements into groups.

Monocular Cues

Depth perception cues that require only one eye.

Binocular Disparity

The slight difference in the image seen by each eye, contributing to depth perception.

Inattentional Blindness

Failing to notice an unexpected stimulus in one's field of vision due to lack of attention.

Top-Down Processing

Using pre-existing knowledge and expectations to organize sensory input.

Bottom-Up Processing

Building a complete perception from smaller sensory features.