Unit 3: Reading and Notes Flashcards
Sensation vs. Perception
Sensation - the process of conducting mental representations of the external world by converting it to neural signals
Perception - how we select, organize, and interpret our sensations
Bottom-up processing
Analysis of stimulus that begins with the sense receptors and works up to the level of the brain
Top-down processing
Information processing guided by high level mental process as we construct perceptions drawing on our experience and expectations
Selective attention
The focusing of conscious awareness on a particular stimulus
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
Inattentional blindness
Failing to see visible objects when our attention is somewhere else
Three steps basic to all our sensory systems
- Receive sensory stimulation (often using specialized receptor cells)
- Transform that stimulation into natural impulses
- Deliver the neural information
Change blindness
Failing to notice changes in the environment
Absolute threshold
The minimum stimulation 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 amid background stimulation. Assumes that there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness
Weber’s Law
The principle that to be perceived as different, two stimuli must differ by a constant percentage, rather than a constant amount
Sensory adaptation
Diminished sensitivity as a consequence of constant stimulation
Perceptual set
A mental predisposition to perceive one thing and not another because of our mental tendencies and previous experiences
How does the human eye see?
Not using light particles itself, but by using wavelength to determine the hue and amplitude to determine intensity
How do the brain and eye work together?
The retina’s receptor cells convert particles of light energy to neural impulses and send them to the brain. The brain reassembles them into an image
Trichromatic Theory
The retina contains three receptor cones, sensitive to red, green, and blue
Opponent Process Theory
Says that we process colors opposed in pairs, red-green, blue-yellow, white-black
Wavelength
The distance from the peak of one wave to the peak of the next
Accommodation
The process by which the eye’s lens changes shape to focus near or far objects on the retina
Feature detectors
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 for many functions, including vision.
Gestalt
German word meaning organized whole. When given a cluster of sensations, people tend to organize them into a meaningful whole (example: Necker’s cube)
Depth perception
How you perceive how far or close something is
How does the brain perceive movement?
The brain computes motion based on its assumption that shrinking objects are retreating and enlarging objects are approaching. It perceived continuous movement in a rapid series of slightly varying images.
Figure ground
The organization of the visual field into objects that stand out from their surrounds
Grouping
The perceptual tendency to organize stimuli into coherent groups
Binocular cues
Depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal disparity
By comparing retinal images from two eyes, the brain computes distance. The greater the disparity between two images, the closer the object
Monocular cues
Depth cues, such as interposition and linear perspective, available to either eye alone
How do perceptual constancies help us organize our sensations into meaningful perceptions
Allow us to recognize objects, regardless of viewing angles, distance, and illumination. Therefore, we can take context into account to create meaningful perceptions
Perceptual adaptation
The ability to adjust to an artificially displaced or even inverted visual field
Audition
The sense or act of hearing
What do we hear best
Human voices (3000 to 4000 Hz)
Frequency
Determined by wavelength of sound, measured in hertz (Hz)
Pitch
A tone’s experienced highness or lowness; depends on frequency
Sensorineural hearing loss
Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves, also called nerve deafness
Conduction hearing loss
Hearing loss caused by damage to the mechanical system that conducts sounds 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
Place Theory
We perceive high and low pitch sounds because the soundwaves will cause the cochlea to vibrate at different places
Frequency Theory
The rate of nerve impulses going through the auditory nerve matches the pitch of the tone
4 ways we perceive touch
Pressure, warmth, cold, and pain
Describe pain.
Varies by gender, triggered by both bottom-up sensations and top-down processing.
How to control pain
Stimulate “gate-closing” activity. Use massage, electric stimulation, or acupuncture.
Phantom limb sensation
When the brain misinterprets the spontaneous central nervous system activity that occurs in the absence of normal sensory input
Olfaction
Odor enters the nasal cavity and stimulates 5 million receptor cells to sense smells. Humans can detect about 10,000 different odors
Vestibular sense
The sense of body movement and position, including the sense of balance
What tastes do we experience?
Sweet, sour, salty, bitter, and umami
Scent and memory
The part of the brain that processes smell is close to the part that processes memories
