Sensation
The process of receiving stimulus energies from the external environment and transforming those energies into neural energies
Perception
The process of organizing and interpreting sensory information so that it has meaning
Bottom-Up
The operation in sensation and perception in which sensory receptors register information about the external environment and send it up to the brain for interpretation
Top-Down
The operation in sensation and perception, launched by cognitive processing at the brain's higher levels, that allows the organism to sense what it is happening and to apply that framework to information from the world
Sensory Receptors
Specialized cells that detect information and transmit it to sensory nerves and the brain
Absolute Threshold
The minimal amount of stimulus energy that a person can detect
Difference Threshold
The degree of difference that must exist between two stimuli before the difference is detected
Weber's Law
The principle that two stimuli must differ by a constant minimum percentage (rather than a constant amount) to be perceived as different
Signal Detection Theory
A theory of perception that focuses on decision making about stimuli in the presence of uncertainty
Hit
You ask, and he or she says yes
Miss
He or she would have said yes, but you do not ask
False Alarm
You think the individual seemed interested, but your offer is politely declined
Correct Rejection
You do not ask the person out, and he or she would have said no
Selective Attention
The process of focusing on a specific aspect of experience while ignoring others
Sensory Adaptation
A change in the responsiveness of the sensory system based on the average level of surrounding stimulation
Retina
The multilayered light sensitive surface in the eye that records electromagnetic energy and converts it to neural impulses for processing in the brain
Rods
The receptor cells in the retina that are sensitive to light, but not very useful for color vision
Cones
The receptor cells in the retina that allow for color perception
Feature Detectors
Neurons in the brain's visual system that respond to particular features of a stimulus
Trichromatic Theory
Theory stating that color perception is produced by three types of cone receptors in the retina that are particularly sensitive to different, but overlapping, ranges of wavelengths
Opponent Process Theory
Theory stating that cells in the visual system respond to complementary pairs of red-green and blue-yellow colors; a given cell might be excited by red and inhibited by green, whereas others might be excited by yellow and inhibited by blue
Gestalt Psychology
A school of thought interested in how people naturally organize their perceptions according to certain patterns
Perceptual Constancy
The recognition that objects are constant and unchanging even though sensory input about them is changing
Place Theory
Theory on how the inner ear registers the frequency of sound, stating that each frequency produces vibrations at a particular spot on the basilar membrane
Cochlea
A spiral structure consisting of fluid filled canals
Basilar Membrane
lines the inner wall of the cochlea and runs its entire length. It is narrow and rigid at the base of the cochlea, but widens and becomes more flexible at the top
Tectorial Membrane
Jellylike flap above the hair cells
Hair Cells
The ear's sensory receptors
Frequency Theory
Theory on how the inner ear registers the frequency of sound, stating that the perception of a sound's frequency depends on how often the auditory nerve fires
Pain
The sensation that warns us of damage to our bodies
Extrasensory Perception
Mental telepathy- no scientific evidence
Tonic Pain
Long lasting, dull, poorly localized pain
Phasic Pain
Brief, sharp, localized pain