Sensation and Perception (Modules 17-22) Flashcards
Sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
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
Describe an example that illustrates the difference between sensation and perception.
A frog’s receptor cells in the eyes fire only in response to small, dark moving objects. If the frog is surrounded by motionless flies, it could starve to death.
Absolute Thresholds
The minimum stimulation needed to detect a particular stimulus 50% of the time
Ex. Smelling a single drop of perfume in a three-room apartment
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 detection depends on experience.
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
Ex. Liking someone more because they give you free food
Difference Threshold
The minimum difference between two stimuli required for detection 50% of the time. We experience the difference threshold as a just noticeable difference.
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)
Sensory Adaptation
Diminished sensitivity as a consequence of constant stimulation
Ex. Moving your watch up your wrist an inch and feeling it only for a few moments
Why do we have sensory adaptation – what is its important benefit?
It gives us the freedom to focus on informative changes in our environment.
Wavelength determines ___.
Frequency
Hue
The dimension of color that is determined by the wavelength of light, or the colors as we know them (blue, green, etc.)
Amplitude determines what?
Intensity of colors
Intensity
The amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude
Cornea
The transparent layer forming the front of the eye
Pupil
The adjustable opening in the center of the eye through which light enters
Iris
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
Lens
The transparent structure behind the pupil that changes shape to help focus images on the retina
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; necessary for peripheral and twilight vision, when cones don’t respond
Cones
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 allow color sensations.
Bipolar Cells
Neural signals from chemical changes in rods and cones activate bipolar cells.
Ganglion Cells
Bipolar cells activate ganglion cells.
Optic Nerve
The nerve that carries neural impulses from the eye to the brain
Blind Spot
The point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there
Fovea
The central focal point in the retina, around which the eye’s cones cluster
After being processed in the retina, the optic nerve carries vision information to what part of the brain?
Thalamus
Feature Detectors
Hubel and Wiesel. Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle or movement.
Parallel Processing
The processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing
Ex. Recognizing a face
Young-Helmholtz Trichromatic Theory
The theory that the retina contains three different color receptors which, when stimulated in combination, can produce the perception of any color
Three colors our eyes are sensitive to according to Young-Helmholtz Trichromatic Theory
Red, Green and Blue
According to this theory, what causes colorblindness?
Lack of functioning red- or green-sensitive cones or both.
Opponent-Process Theory
Hering. The theory that opposing retinal processes enable color vision.
3 sets of colors according to Opponent-Process Theory
Red-green, yellow-blue, black-white
Afterimages
The image you see after staring at something for a while then looking at a white surface. The afterimages are in the inverse color. If the original color was red, the afterimage would be green.
Audition
The sense or act of hearing
Amplitude determines ___.
Volume
Frequency determines ___.
Pitch
What is sound measured in?
Decibels
Eardrum
Thin, cone-shaped membrane that separates the external ear from the middle ear
Three bones in middle ear
Hammer, anvil, stirrup
Cochlea
A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
Vibrations cause the cochlea’s membrane to shake. This causes ripples in the ___, bending the ___ lining its surface.
Basiliar membrane, hair cells
Hair cells convert the messages into neurons that are then sent by the ___ to the thalamus, then onto the ___ cortex in the ___ lobe.
auditory nerve, auditory, temporal
What is the difference between sensorineural hearing loss and conduction hearing loss?
Sensorineural hearing loss occurs when there is damage to the inner ear whereas conductive hearing loss occurs when sound is not conducted efficiently through the outer ear.
Cochlear implant
A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
How do we interpret loudness of a sound?
Number of activated hair cells
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
Volley Principle
Neural cells can alternate firing
How do we locate the source of sounds?
One ear hearing a sound slightly more intense and slightly sooner
What are the four distinct skin senses that make up touch?
Pressure, warmth, cold and pain
Kinesthesia
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 biological parts for your sense of equilibrium located?
Inner ear
Why do you need to feel pain?
It is a signal that something is wrong.
Gate Control Theory
For pain, the theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass onto the brain
What are phantom limb sensations?
When the body misinterprets the spontaneous central nervous system activity that occurs in __
List two examples of psychological influences of pain
1) Visibly seeing a rubber finger bend backwards and feeling pain
2) Immersing hand in cold water for longer even though there is more net pain
List two examples of social-cultural influences of pain
1) Feeling empathy for another’s pain
2) Seeing someone else get hurt and feeling pain
What are the four basic tastes?
Sweet, sour, salty, bitter
What is the newest 5th one? Describe it.
Umami, savory/meaty
Taste is a chemical sense. What does that mean for how it works?
Taste buds have receptors that respond predominantly to one of the five tastes.
What is the scientific name for smell?
Olfaction
Because it is a primitive sense, what part of the brain does smell bypass?
Thalamus
Do we have a distinct receptor for each detectable odor?
Yes
Sensory Interaction
The principle that one sense may influence another, as when the smell of a food influences its taste
Ex. When you plug your nose while eating a Skittle, the flavor is less intense than when your nose isn’t plugged.
Gestalt
An organized whole. Emphasis on our tendency to integrate pieces of information into one coherent piece of information.
What is the fundamental truth underlying all of the Gestalt principles?
Our brain does more than register information about the world. We organize information to make sense of it.
Figure-ground
The organization of the visual field into objects (the figures) that stand our from their surroundings (the ground)
Grouping
The perceptual tendency to organize stimuli into coherent groups
Proximity
We group nearly objects together.
Continuity
We perceive smooth, continuous patterns rather than discontinuous ones.
Closure
We fill in gaps to complete a whole object.
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
What did the visual cliff experiments demonstrate – is depth perception learned or not?
Depth perception is not learned; it’s something you’re born with
Binocular Depth Cues
Depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal Disparity
A binocular cut for perceiving depth: By comparing imagines from the retinas in the two eyes, the brain computes distance – the greater the disparity between images, the closer it is.
Monocular Depth Cues
Depth cues, such as interposition and linear perspective, available to enter one eye alone
Relative Height
Objects higher in our field of vision are perceived as farther away; causes illusion that taller objects are longer than short objects
Relative Size
If we assume two objects are similar in size, we perceive the one that casts the smaller retinal image as farther away
Interposition
If one object partially blocks the view of another, we perceive it as closer
Relative Motion
As we move, objects that are stationary appear to move; the closer the object, the faster it appears to move
Linear Perspective
Parallel lines seem to converge with distance
Light and Shadow
Nearby objects reflect more light to our eyes, dimmer objects seem farther away
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 shapes, size, lightness and color_ even as illumination and retinal images change
Ex. Door don’t change size, shape or color even if they appear to do so based on what angle we look at it and if it’s light or dark in the room.
Color Constancy
Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Example of size constancy
A person appears to get smaller as they run away, but the brain doesn’t perceive this as shrinking
Example of shape constancy
A door casts an increasingly trapezoidal image on our retinas as it opens, yet we still perceive it as rectangular
Perceptual Adaptation
In vision, the ability to adjust to an artificially displaced or even inverted visual field
Ex. Lincoln’s upside-down face
Perceptual Set
A mental predisposition to perceive one thing and not another
Human Factors Psychologists
Psychologists that explore how people and machines interact and how machines and physical environments can be made safe and easy to use
ESP
Extrasensory perception. 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
