Chapter Six Flashcards
sensation
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
sensory receptors
sensory nerve endings that respond to stimuli.
perception
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
bottom-up processing
analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information.
top-down processing
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.
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.
psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.
What is the rough distinction between sensation and perception?
Sensation is the bottom-up process by which your sensory receptors and nervous system receive and represent stimuli. Perception is the top-down process by which your brain creates meaning by organizing and interpreting what your senses detect.
absolute threshold
the minimum stimulus energy needed to detect a particular stimulus 50 percent of the time.
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 that detection depends partly on a person’s experience, expectations, motivation, and alertness.
subliminal
below one’s absolute threshold for conscious awareness.
priming
the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response.
difference threshold
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (or jnd).
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).
Using sound as your example, explain how these concepts differ: absolute threshold, subliminal stimulation, and difference threshold.
Absolute threshold is the minimum stimulation needed to detect a particular sound (such as an approaching bike on the sidewalk behind you) 50 percent of the time. Subliminal stimulation happens when, without your awareness, your sensory system processes a sound that is below your absolute threshold. A difference threshold is the minimum difference needed to distinguish between two stimuli (such as between the sound of a bike and the sound of a runner coming up behind you).
sensory adaptation
diminished sensitivity as a consequence of constant stimulation.
Why is it that after wearing shoes for a while, you cease to notice them (until questions like this draw your attention back to them)?
The shoes provide constant stimulation. Thanks to sensory adaptation, we tend to focus primarily on changing stimuli.
perceptual set
a mental predisposition to perceive one thing and not another.
Does perceptual set involve bottom-up or top-down processing? Why?
It involves top-down processing, because it draws on your experiences, assumptions, and expectations when interpreting stimuli.
wavelength
the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of gamma rays to the long pulses of radio transmission.
hue
the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
intensity
the amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height).
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.
accommodation
the process by which the eye’s lens changes shape to focus near or far objects on the retina.
rods
retinal receptors that detect black, 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. Cones detect fine detail and give rise to color sensations.
optic nerve
the nerve that carries neural impulses from the eye to the brain.
Some nocturnal animals, such as toads, mice, rats, and bats, have impressive night vision thanks to having many more___________(rods/cones) than___________(rods/cones) in their retinas. These creatures probably have very poor___________(color/black-and-white) vision.
rods; cones; color.
Cats are able to open their___________much wider than we can, which allows more light into their eyes so they can see better at night.
pupils
Young-Helmholtz trichromatic (three-color) theory
the theory that the retina 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.
opponent-process theory
the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.
What are two key theories of color vision? Are they contradictory or complementary? Explain.
The Young-Helmholtz trichromatic theory shows that the retina contains color receptors for red, green, and blue. The opponent-process theory shows that we have opponent-process cells in the retina and thalamus for red-green, yellow-blue, and white-black. These theories are complementary and outline the two stages of color vision: (1) The retina’s receptors for red, green, and blue respond to different color stimuli. (2) The receptors’ signals are then processed by the opponent-process cells on their way to the visual cortex in the brain.
feature detectors
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.
parallel processing
processing many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision.
What is the rapid sequence of events that occurs when you see and recognize a friend?
Light waves reflect off the person and travel into your eyes. Receptor cells in your retina convert the light waves’ energy into millions of neural impulses sent to your brain. Your brain’s detector cells and work teams process the subdimensions of this visual input—including color, movement, form, and depth—separately but simultaneously. Your brain interprets this information, based on previously stored information and your expectations, and forms a conscious perception of your friend.
gestalt
an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.
figure-ground
the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
grouping
the perceptual tendency to organize stimuli into coherent groups.
In terms of perception, a band’s lead singer would be considered ____________ (figure/ground), and the other musicians would be considered ______________ (figure/ground).
figure; ground.
What do we mean when we say that, in perception, “the whole may exceed the sum of its parts”?
Gestalt psychologists used this saying to describe our perceptual tendency to organize clusters of sensations into meaningful forms or coherent groups.
depth perception
the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.
visual cliff
a laboratory device for testing depth perception in infants and young animals.
binocular cue
a depth cue, such as retinal disparity, that depends on the use of 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.
monocular cue
a depth cue, such as interposition or linear perspective, available to either eye alone.
How do we normally perceive depth?
We are normally able to perceive depth thanks to (1) binocular cues (such as retinal disparity), and (2) monocular cues (which include relative height, relative size, interposition, linear perspective, light and shadow, and relative motion).
phi phenomenon
an illusion of movement created when two or more adjacent lights blink on and off in quick succession.
perceptual constancy
perceiving objects as unchanging (having consistent color, brightness, shape, and size) even as illumination and retinal images change.
perceptual adaptation
the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field.
audition
the sense or act of hearing.
frequency
the number of complete wavelengths that pass a point in a given time (for example, per second).
pitch
a tone’s experienced highness or lowness; depends on frequency.
middle ear
the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window.
cochlea
[KOHK-lee-uh] a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.
inner ear
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.
sensorineural hearing loss
hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; the most common form of hearing loss, also called nerve deafness.
conduction hearing loss
a less common form of hearing loss, caused by damage to the mechanical system that conducts sound waves to the cochlea.
cochlear implant
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.
What are the basic steps in transforming sound waves into perceived sound?
The outer ear collects sound waves, which are translated into mechanical waves by the middle ear and turned into fluid waves in the inner ear. The auditory nerve then translates the energy into electrical waves and sends them to the brain, which perceives and interprets the sound.
The amplitude of a sound wave determines our perception of___________(loudness/pitch).
loudness.
The longer the sound waves, the___________(lower/higher) their frequency and the___________(higher/lower) their pitch.
lower; lower
place theory
in hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated.
frequency theory
in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. (Also called temporal theory.)
Which theory of pitch perception would best explain a symphony audience’s enjoyment of a high-pitched piccolo? How about a low-pitched cello?
place theory; frequency theory
gate-control theory
the theory that 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 the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.
hypnosis
a social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur.
Which of the following options has NOT been proven to reduce pain?
Distraction
Hypnosis
Phantom limb sensations
Endorphins
c.
dissociation
a split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others.
posthypnotic suggestion
a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized; used by some clinicians to help control undesired symptoms and behaviors.
How does our system for sensing smell differ from our sensory systems for touch and taste?
We have four basic touch senses and five taste sensations. But we have no specific smell receptors. Instead, different combinations of odor receptors send messages to the brain, enabling us to recognize some 1 trillion different smells.
kinesthesia
[kin-ehs-THEE-zhuh] the system for sensing the position and movement of individual body parts.
vestibular sense
the sense of body movement and position, including the sense of balance.
Where are the kinesthetic receptors and the vestibular sense receptors located?
Kinesthetic receptors are located in our joints, tendons, and muscles. Vestibular sense receptors are located in our inner ear.
sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste.
embodied cognition
the influence of bodily sensations, gestures, and other states on cognitive preferences and judgments.
extrasensory perception (ESP)
the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition.
parapsychology
the study of paranormal phenomena, including ESP and psychokinesis.
If an ESP event occurred under controlled conditions, what would be the next best step to confirm that ESP really exists?
The ESP event would need to be reproduced in other scientific studies.
