Chapter 6 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 by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.
Bottom-Up Processing
starts at your sensory receptors and works up to higher levels of processing.
Top-Down Processing
constructs perceptions from this sensory input by drawing on your experience and expectations.
Transduction
Conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, smells, into neural processes 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.
Absolute Threshold
The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time. Can be affected by our mental state.
Signal Detection Theory
A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes there is no single absolute threshold, and that detection depends partly on a person’s experience, expectations, motivations, and alertness.
Subliminal
below one’s absolute threshold for conscious awareness.
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.
Webers Law
the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).
Sensory Adaptation
diminished sensitivity as a consequence of constant stimulation. This occurs because our nerve cells fire less frequently.
Perceptual Set
a mental predisposition to perceive one thing and not another.
The Effectors of Perception
Context, Emotion, and Motivation
Wavelength
the distance from the peak of one light or sound wave to the peak of the next.
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.
Wavelength and Hue Relationship
Short wavelength equals high frequency (bluish colors)
Long wavelength equals low frequency (reddish colors)
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). Great amplitude equals bright colors and vice versa.
Cornea
bends light to help provide focus.
Pupil
a small adjustable opening.
Iris
a colored muscle that dilates or constricts in response to light intensity, surrounding the pupil and controlling its size. Each iris is so distinctive that iris-screening technology can often confirm identity. The iris can also respond to emotional states.
Lens
a transparent structure that focuses light rays into an image on the retina by using accommodation.
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. Can detect pressure, but brain perceives it as light.
Accommodation
the process by which the eye’s lens changes shape to focus near or far objects on the retina.
Steps of Light Perception
- Light enters through the cornea.
- Light passes through the pupil.
- Light hits the lens.
- Lens focuses rays into an image on the retina.
- Light moves though the retina and triggers chemical reaction in rods and cones.
- The chemical reaction activates bipolar cells.
- Bipolar cells activate the ganglion cells, whose combined axons form the optic nerve.
- The optic nerve transmits information via the thalamus to the brain’s visual cortex.
Rods
retinal receptors that detect black, white, and gray, and are sensitive to movement. Rods are necessary for peripheral and twilight vision, when cones don’t respond. Located in the retina’s outer regions with no direct connection with the brain. No direct connection to brain.
Cones
retinal receptors that are concentrated near the center of the retina and that function in the daylight or in well-lit conditions. Cones detect fine detail and give rise to color sensations. Direct connection to brain.
Fovea
the central focal point in the retina, around which the eye’s cones cluster.
Optic Nerve
the nerve that carries neural impulses from the eye to the brain. Can send up to 1 million messages at once.
Blind Spot
the point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there. The brain fills the blind spot with information.
Young-Helmholtz Trichromatic 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.
Tetra-chromatic Color Vision
a condition where a person (usually female) can see up to 100 million different colors.
Color Deficient Vision
a condition where a person (usually male) lacks certain color-sensitive cones (usually one or two), making it impossible to distinguish colors of their receptors.
Opponent-Process Theory
the theory that opposing retinal processes (red-green, blue-yellow, 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. Opposing colors can’t travel simultaneously because they flow in the same channel, so we see only red or green, not a mixture. This theory explains after-images.
Stages of Color Processing
- The retina’s red-, green-, and blue-sensitive cones respond in varying degrees to different color stimuli, as the Young-Helmholtz Trichromatic Theory suggested.
- The cones’ responses are then processed by opponent-process cells, as Herring’s Opponent-Process Theory proposed.
Feature Detectors
nerve cells in the brain’s visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement. The fusiform face area helps us to identify faces from friends and strangers. Stimulation of this area may cause you to perceive faces, but damage to this area may cause you to lose the ability to recognize familiar faces. You would still be able to recognize other objects, since face perception occurs separately form object perception.
Gesalt
An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.
Figure-Ground Perception
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.
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. We use this to judge the distance of nearby objects.
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.
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 Interpretation in Previously Blind People
People who are born blind and later gain the ability to see have only some visual perception abilities. They cannot visually recognize objects that were familiar by touch. (ex. distinguishing circle from square). This happens because there is a critical period for vision.
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.
Sound Waves
Sound waves are air molecules that bump into each other, creating waves of compressed and expanded air. The height of a sound wave determines its perceived loudness. Their frequency determines their pitch. Long waves have low frequency meaning low pitch, and vice versa.
Frequency
the number of complete wavelengths that pass a point in a given time.
Pitch
a tone’s experienced highness or lowness; depends on frequency.
Eardrum
a tight membrane that vibrates when sound waves strike it.
Middle Ear
the chamber between the eardrum and cochlea containing three tiny bones—hammer (malleus), anvil (incus), and stirrup (stapes)—that concentrate the vibrations of the eardrum on the cochlea’s oval window.
Cochlea
a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses. Contains many hair cells to detect vibrations.
Inner Ear
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.
Steps to Hearing Sounds
Steps to Hearing Sounds
1. Sound waves strike the eardrum.
2. The middle ear pricks up vibrations and transmits them to the cochlea.
3. These vibrations cause the cochlea’s membrane-covered opening (oval window) to vibrate, jostling the fluid inside the cochlea.
4. This motion causes ripples in the basilar membrane, bending the hair cells lining its surface.
5. The hair movements trigger impulses in adjacent nerve cells, whose axons converge to form the auditory nerve.
6. The auditory nerve carries the neural messages to the thalamus, and then on to the auditory cortex in the brain’s temporal lobe.
Sensorineural Hearing Loss
the most common form of hearing loss, caused by damage to the cochlea’s receptor cells or to the auditory nerve; also called nerve deafness. Can cause someone to be able to hear sound but have trouble discerning what someone else is saying.
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. Hearing also has a critical period, so these implants only work on children and adults who learned to process sounds as a child.
Interpreting Loudness
The brain interprets loudness from the number of activated hair cells. If a hair cell loses sensitivity to soft sounds, it may still retain the same intensity for loud sounds.
Place Theory
in hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated (also called place coding). Only explains how we hear high pitches.
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 coding).
Locating Sounds
Humans having two ears is beneficial for locating sounds. Sounds to the right will cause the right ear to receive a more intense sound and receive that sound slightly sooner than the left ear. The differences are extremely small, but our auditory system can detect the most minute changes and locate the sound accordingly.
Touch
The four types of touch: pressure, warmth, cold, and pain. Different parts of the body are sensitive to different types.
Pain
The body’s way of telling you that something has gone wrong. Without these warnings, we may wear out a joint or not detect an infection.
Pain as a Biopsychosocial Event
Biological: Sensory receptors called nociceptors detect hurtful temperatures, pressure, or chemicals. Your experience of pain depends in part on the genes you inherited and on your physical characteristics.
Psychological: Focusing attention elsewhere can decrease pain sensations, while focusing just on the pain may increase it. People can edit their memories of pain, usually only considering the peak amount of pain, and how much pain was felt at the end. If people felt a higher peak of pain but a lower feeling of pain at the end, they usually prefer this over a constant severity of pain.
Social: We tend to experience more pain when others also seem to be experiencing pain, because feeling empathy towards others pain tends to cause one’s own brain activity to partially mimic it.
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 (which conduct most pain signals) and is closed by activity in larger fibers (activated by massage, electrical stimulation, or acupuncture) or by information coming in from the brain (distraction).
Controlling Pain
Pain can be controlled through drugs, surgery, acupuncture, electrical stimulation, massage, exercise, hypnosis, relaxation training, mediation, and thought distraction.
Social Influence Theory
suggests that hypnosis is a by-product of normal social and mental processes. People may begin to act like they are being hypnotized, which will cause them to feel and behave in ways like a good hypnotic subject and will ultimately distract them from the pain.
Dissociation Theory
proposes that hypnosis is a special dual-processing state of dissociation. This offers an explanation as to why previously hypnotized people carry out posthypnotic suggestions. It also explains why people hypnotized for pain relief may show brain activity in areas that receive sensory information, but not in areas that normally process pain-related information.
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.
Gustation
our sense of taste. There are 5 primary taste sensations: sweet, sour, salty, bitter, and umami.
Taste Process
In each taste bud, there are receptors that project antenna-like hairs to detect food molecules. These receptors respond to one specific type of sensation. Then, each receptor transmits its message to its partner cell located in the brain’s temporal lobe. Taste receptors replace themselves every week or two, but as you grow older, the number of taste buds and sensitivity decreases. Expectations can also influence taste.
Olfaction
our sense of smell
Smell Process
Molecules of a substance carried in the air reach a tiny cluster of receptor cells at the top of each nasal cavity. Instantly, they alert the brain through their axon fibers. Olfactory neurons bypass the thalamus (sensory control center), since smell is an old sense. We do not have a distinct receptor for each detectable odor. Different odor molecules can bind to different receptors simultaneously, allowing us to have a wide detectable smell base.
Kinesthesia
our movement sense—our system for sensing the position and movement of individual body parts.
Vestibular Sense
our balance sense—our sense of body movement and position that enables our sense of balance.
Sensory Interaction
the principle that one sense can 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 judgements.
Extrasensory Perception (ESP)
the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition. This DOES NOT EXIST.
Parapsychology
the study of paranormal phenomena, including ESP and psychokinesis.
