The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.
Minimum stimulation to detect a particular stimulus 50% of the time.
Minimum difference between two stimuli that a subject can detect 50% of the time. The more intense a stimulus, the larger the increment needed to notice a difference.
Signal Detection Theory
Predicts how and when we detect the presence of a faint stimulus and background stimulation.
Below one's absolute threshold for conscious awareness.
The activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.
To perceive a difference between two stimuli, they must differ by a constant minimum percentage.
Diminished sensitivity with constant stimulation. After constant exposure to a stimulus, our nerve cells fire less frequently.
The focusing of conscious awareness on a particular stimulus.
The conversion of one form of energy into another.
The distance from the peak of one light or sound wave to the peak of the next.
The dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
The amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude. Large amplitude=bright color, loud sound while small amplitude=dull color, light sound.
The adjustable opening in the center of the eye through which light enters.
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
The transparent structure behind the pupil that changes shape to help focus images on the retina.
The process by which the eye's lens changes shape to focus near or far objects on the retina.
The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.
The sharpness of vision.
A condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina.
A condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind the retina.
Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.
Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
The nerve that carries neural impulses from the eye to the brain.
The point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there.
The central focal point in the retina, around which the eye's cones cluster.
Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.
The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions; including vision.
Young-Helmholtz Trichromatic Theory
The retina contains three different color receptors--one most sensitive to red, another to green, and another to blue. When stimulated in combination these can produce the perception of any color.
Opposing retinal processes enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.
Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.
The number of complete wavelengths that pass a point in a given time.
The sense or act of hearing
A tone's experienced highness or lowness, depends on frequency.
Pinna or Auricle is the outer ear. It plays a role in the spatial focusing of hearing.
(Air filled). The Tympanic Membrane or eardrum - a thin, rigid, semi-transparent membrane between the external and middle ear. It vibrates when sound waves hit it, passing those vibrations on to the ossicles.
Bones of the middle ear - connect the external ear to the inner ear. The Malleus or hammer is attached to the inner aspect of the tympanic membrane. The Incus or anvil connects the malleus to the stapes. And the Stapes or stirrup is attached to the oval window.
(Fluid filled). Converts mechanical energy to neural impulses. The Vestibule - antechamber to both the semicircular canals and the cochlea. Also helps with balance. The semicircular Canals - there are 3 semicircular canals; superior, lateral, and posterior. These are fluid filled and help detect angular acceleration. This helps with balance, etc.
A snail shaped chamber where the sound waves are converted into neural impulses.
Runs the length of the cochlea and covered by hair cells/sensory neurons. When the Basilar Membrane bends in response to the wave traveling through the surrounding fluid, the hair cells are stimulated.
The theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.
The rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
When the ear looses the ability to conduct a sound wave.
Nerve (sensorineural) deafness
Damage to the cilia. can be treated by a hearing aid or a cochlear implant.
A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.
The spinal cord contains a neurological gate that blocks pain signals or allows them to pass on to the brain. The gate is opened by activity in small nerve fibers and closed by activity in large fibers or info from the brain.
One sense may influence another
An extreme sensitivity to something that others would only find mildly painful.
The system for sensing the position and movement of individual body parts.
The sense of body movement and position, including the sense of balance.
when the ear hears one sounds, but the eye sees a mouth form a different sound, the brain's interpretation can be a mixture of the two sounds
One sort of sensation produces another
When vision competes with other senses, vision usually wins.
An organized whole
The organization of the visual field into objects that stand out from their surroundings.
The perceptual tendency to organize stimuli into coherent groups.
Seeing objects in three dimensions, allowing us to judge distance.
A device for testing depth perception in infants and young animals.
Depth cues that depend on the use of two eyes.
A binocular cue for perceiving depth, by comparing images from the two eyeballs, the brain computes distance. The greater the difference, the closer the object.
A binocular cue for perceiving depth, the extent to which the eyes converge inward when looking at an objects. The greater the inward strain, the closer the object.
Depth cues available to either eye alone
If two objects are similar in size, we perceive the one that casts the smaller retinal image as farther away.
If one object partially blocks our view of another, we perceive it as closer.
Because light from distant objects passes through more atmosphere, we perceive hazy objects as farther away from sharp, clear objects.
A gradual change from a coarse, distinct texture to a fine, indistinct texture signals increasing distance. Objects far away appear smaller and more densely packed.
We perceive objects higher in our field of vision as farther away. This may contribute to the illusion that vertical dimensions are longer than identical horizontal dimensions.
As we move, objects that are actually stable may appear to move.
Parallel lines appear to converge with distance.
Nearby objects reflect more light to our eyes.
The Phi Phenomenon
An illusion of movement created when two or more adjacent lights blink on and off in quick succession.
Perceiving objects as unchanging even as illumination and retinal images change.
The ability to adjust to an artificially displaced or even inverted visual field.
A mental predisposition to perceive one thing and not another.
The study of paranormal phenomena.
Extrasensory Perception (ESP)
Perception can occur apart from sensory input.
Perceiving remote events
Perceiving future events
Our sense of touch is actually a mix of at least four distinct skin senses-pressure, warmth, cold, and pain.
When you are attending to something, you might miss something else.
Illusion with monsters/red boxes. They are actually the same size.
Lines with arrows, they are actually the same size.
Human Factors Psychology
Explores how people and machines interact and how machines and physical environments can be made safe and easy to use.