Sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. (converts it into neural signals).
Perception
The process of organizing, selecting, and interpreting sensory information enabling us to recognize meaningful objects and events.
Bottom-up Processing
the entry level analysis of sensations. Also called feature analysis. It works up to the brain’s integration of sensory information.
Top-down Processing
is the analysis of sensation drawing on experience and expectations. Our experiences create schemata, which are mental representations of how we expect the world to be, Schemata can create a perceptual set, which is predisposition to perceive something in a certain way. Guided by higher level mental processes.
Psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.
Absolute Threshold
the minimum stimulus energy needed to detect a particular stimulus 50% of the time. The weakest amount of stimulus that people that a person can detect 50% of the time.
Difference Threshold
The minimum difference between two stimuli required for detection 50% of the time. We experience the ________ _______ as a just noticeable difference.
Subliminal Threshold
Below ones absolute threshold for conscious awareness.
Weber’s Law
The principle that, to be perceived as different, two stimuli must differ by a constant minimum PERCENTAGE (rather than a constant amount).
Signal Detection Theory
A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and the detection depends partly on a person’s experience, expectations, motivation, and alertness.
Sensory Adaptation
Diminished sensitivity as a consequence of constant stimulation
Transduction
conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret.
Perceptual Set
a mental predisposition to perceive one thing and not another.
Sensory Receptors
sensory nerve endings that respond to stimuli
Priming
the activation, often unconsciously, of certain associations, thus predisposing one’s perceptions, memory, or response.
wavelength of lightwave
the distance from one light or sound wave to the peak of the next.
amplitude of a lightwave
the distance from the peak of one light or sound wave to the pea of the next. Height of the wave,influences brightness in visual perception.
cornea
Light enters through the ______, a protective covering. Contributes most of the eyes focusing power.
iris
the colored muscle that expands and contracts to change the size of the opening (pupil) for the light.
pupil
light goes through the _____, which can open and close to allow more or less light in.
lens
focuses the light rays on the retina
retina
the light sensitive inner surface of the eye, containing the receptor rods and cone plus layers of neurons that begin the processing of visual information.
accommodation
the process by which the yes lens changes shape to focus near or far objects on the retina
fovea
the central focal point in the retina, around which the eyes cones cluster
optic nerve
the nerve that carries neural impulses from the eye to the brain
thalamus
the sensory processing center of the brain. Processes every sense except smell
blindspot
the point at which the optic nerve leaves the eye creating a “blind” spot because there are no receptor cells located there.
nearsighted
a condition in which nearby objects are seen more clearly than distant objects
farsighted
a condition in which faraway objects are seen more clearly than near objects
rods
retinal receptors that detect block, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision, when cones don’t respond
cones
retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Detect fine detail and give rise to color sensations
feature detectors
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angles or movement.
parallel processing
processing many aspects of a problem simultaneously; the brain’s natural made of information processing for many functions, including vision.
young-helmoltz trichromatic theory
the theory that the retention contains three different types of color receptors-one most sensitive to red, one to green, one to blue-which, when stimulated in combination, can produce the perception of any color.
color blindness
the lack in function of certain light receptors (cones) within the retina (most common red-green)
opponent process theory
the theory that opposing retinal processes (red-green, yellow-blue, white-black)) marble color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.
gestalt psycholog
the organized whole. Emphasized our tendency to integrate pieces of information into meaningful wholes.
figure-ground
an organization of the visual field into objects (the figure) that stand out form the surroundings (the ground)
depth perception
the ability to see objects in three dimensions although the images that strike the retina is 2 dimensions. Allows us to judge distance.
visual cliff
a laboratory devise for testing depth perception in infants and young animals.
monocular cues
a depth cue, such as interposition or linear persepctive-available to either eye alone
binocular cues
a depth cue, such as retinal disparity that depends on the use of the two eyes
retinal disparity
a binocular cue for perceiving depth. By comparing retinal images from the two eyes, the brain computes distance-the greater the disparity(difference) between the two images, the closer the object.
relative size
if we amuse two objects are similar in size, most people perceive the one that casts the smallest retinal image as further away.
interposition
if one object partially blocks our view of another, we perceive it as closer.
relative height
we perceive objects higher in our field of vision as farther away.
relative motion
as we move, objects that are actually stable may appear to move.
linear perspective
parallel lines appear to meet in the distance. The sharper the angle of the convergence, the greater the perceived distance.
light and shadow
shading provides a sense of depth consistence with our assumption that light comes from above.
phi phenomenon
an illusion of movement created when two or more adjacent lights blink on and off in quick succession.
perceptual constancy
perceiving objects and unchanging (having constant color, brightness, shape, and size even as illumination and retinal images change
perceptual adaptation
the ability to adjust to changed sensory inputs, including an artfully displaced or even inverted visual field.
perceptual set
a temporary readiness to perceive certain objects or events rather than others. For example, a person driving a car has a perceptual set to identify anything in the car or on the road that might affect his or her safety
dichotic listening
an experimental technique where different messages are transmitted into each ear of a subject to test “selective attention” or the ability to concentrate on one messages to the exclusion of the other.
hue
the dimension of color that is determined by the wavelength of light is known as____. The quality by which we distinguish one color from another, as a red from a yellow, a green, a blue or a purple.
intensity
the amount of energy in a light or sound wave, which we perceive as brightness or loudness.
tectum
is responsive for auditory and visual processing and control of eye movements.
grouping
the perceptual tendency to organize stimuli into coherent groups.