Sensation
Process by which our sensory receptors and nervous system receive stimulus energy.
Perception
Process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
Bottom-Up Processing
Analysis begins with sensory receptors and works up to brain's integration of sensory information.
Top-Down Processing
Information processing guided by higher mental processes, or drawing perceptions based on our experiences.
Psychophysics
Study of how physical energy relates to our psychological experience.
Threshold
Edge or boundary.
Absolute Threshold
Minimum stimulation needed to detect a particular stimulus.
Signal Detection Theroy
Detection of a stimulus depends on the intensity of the stimulus, and the physical and psychological state of the individual.
Subliminal Perception
Below one's absolute threshold for conscious awareness.
Difference Threshold
Minimum difference a person can detect between any two stimuli 50% of the time.
Weber's Law
To be perceived as different, two stimuli must differ by a constant proportion (rather than a constant amount).
Sensory Adaptation
Diminished sensitivity as a result of constant stimulation.
Transduction
Sensory systems convert stimulus energy into neural messages.
Cornea
The rounded transparent covering that protects the eye, and allows light in and focuses light waves into small beams.
Iris
Ring of muscle tissue that forms colored portion of eye around pupil.
Pupil
Round opening at front of eye that admits light.
Lens
Transparent structure behind pupil that changes shape to focus images on the retina.
Retina
Light sensitive inner surface of eye.
Rods
Visual receptor cells located on edge of retina, which detect black, white, gray and movement.
Cones
Visual receptor cells located in center of retina that detect color and sharp details.
Blind Spot
A point at which optic nerve leaves the eye.
Fovea
Central focal point in retina, where eye's cones cluster.
Nearsightedness
Nearby objects seen more clearly, because objects focus in front of retina.
Farsightedness
Faraway objects seen more clearly, because objects focus behind retina.
Young-Helmholtz Trichromatic Theory
The retina contains receptor cells that are "tuned" to detect red, green or blue.
Opponent Process Theory
Color is processed in opponent pairs (red-green, yellow-blue, and black-white).
Afterimages
The result of the opponent process theory.
Color Constancy
Perceiving familiar objects as having consistent color, even if light reflecting off of the object changes; context influences our thinking.
Parallel Processing
Process several aspects of a problem simultaneously.
PlaceTheory
The pitch (high or low frequencies) we hear is determined by which areas ("place") of the cochlea are stimulated.
Frequency Theory
The rate ("frequency") of nerve pulses traveling up the auditory nerve matches the frequency of the tone.
Conduction Hearing Loss
Damage to the mechanical system that sends sound waves to the cochlea (i.e. - a punctured eardrum).
Sensorineural Hearing Loss
Damage to the cochlea's hair cell receptors or their nerves (i.e. - aging, heredity, prolonged exposure to loud noise).
Synesthesia
Two senses are sensed at the same time.
Sensory Interaction
One sense may influence another.
Gate-Control Theory
The spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain.
Kinesthesia (Kinesthetic Sense)
Sensing the position and movement of individual body parts, along with muscles, tendons and joints.
Vestibular Sense
The sense of body orientation and balance.
Cochlea
A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger neural impulses.
Hair Cells
The receptor cells of hearing; located in the cochlea where sound waves are changed to neural impulses.
Auditory Nerve
Carries sound information from the ears to the thalamus, and then to the auditory cortex of the temporal lobe.
Frequency
The number of complete wavelengths that pass a point in a given time (i.e. - per second).
Pitch
A tone's highness or lowness (length), depends on frequency of sound waves.
Selective Attention
Focusing conscious awareness on a particular stimulus, while excluding others.
Inattentive Blindness
Inability to see an object that is present.
Change Blindness
Person viewing a visual scene fails to detect large changes in the scene.
Figure-Ground Relationships
The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
Similarity
The tendency to place items that look similar into same group.
Proximity
If objects are close together, we place them in the same group.
Closure
The brain's tendency to look for the whole (not parts) drives us to fill in gaps in a perceptual field.
Continuity
Once an object appears to move in a particular direction, your brain thinks that movement continues unchanged.
Visual Cliff
The laboratory device for testing depth perception in infants and young animals.
Binocular Cues
Depth cues that require the use of both eyes.
Monocular Cues
Depth cues that require the use of only one eye.
Retinal Disparity
The difference between the images you see with the retinas in your left and right eyes.
Convergence
Tension in the eye muscles when the eyes track inward to focus on objects close to the viewer.
Relative Size
The monocular cue that states that if an object seems larger, it is probably closer, and if an object is smaller, it is probably distant.
Relative Motion
The monocular cue that states that an object's apparent slowness indicates the object's distance.
Interposition
The monocular cue that states that closer objects partially obstruct the view of more distant objects.
Relative Height
The monocular cue that states that distant objects appear higher in your field of vision than close objects do.
Texture Gradient
The monocular cue that states that distant objects usually have a much smoother texture than nearby objects.
Relative Clarity
The monocular cue that states that distant objects are less clear than nearby objects are.
Linear Perspective
The monocular cue that states that parallel lines seem to draw together in the distance.
Stroboscopic Motion
A series of slightly varying still images.
Phi Phenomenon
Creating the illusion of movement when fixed lights are turned on and off.
Perceptual Constancy
Perceiving the shape, size, and lightness of an object as unchanging, even as retinal image of object changes.
Perceptual Set
A mental predisposition to perceive one thing and not another.
Perceptual Adaptation
In vision, the ability to adjust to artificially displaced or even inverted visual field.
Extrasensory Perception (ESP)
The claim that perception can occur apart from sensory input.
Precognition
A knowledge of future events.
Telepathy
An ability to exchange thoughts with another person.
Clairvoyance
An ability to "see" remote events.
Psychokinesis
Mind over matter (levitating).
Parapsychology
The study of paranormal phenomenon.
Sound Localization
Locating the direction of a sound depends upon one ear hearing the sound first, and one ear hearing a louder, more intense sound.
5 Taste Sensations
Sweet, sour, salty, bitter, and umami.
Olfactory Bulb
The portion of the brain that receives neural input about odors.
4 Skin Sensations
Warm, cold, pressure, and pain.
Cocktail Party Effect
Focusing your listening attention on a single talker among a mixture of conversations.
Grouping
The perceptual tendency to organize stimuli into understandable groups.
Connectedness
The perception of uniform or linked spots, lines, or areas as a single unit.
Visual Capture
When visual and other sensory information conflict, our brain resolves the conflict by accepting visual data.
Depth Perception
The ability to see in three-dimensions and gauge the distance to an object.