Unit 4: Sensation and Perception 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.
Selective attention
The focussing of conscious awareness on a particular stimulus.
Inattentional blindness
failing to see visible objects when our attention is directed elsewhere
Change blindness
Failing to notice changes in the environment.
Choice blindness
failure to recall a choice immediately after we have made that choice
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 stimulation needed to detect a particular stimulus 50% of the time.
Signal detection theory
A theory predicting how and when we detect a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends on a person’s experience, expectations, motivations, and alertness.
Subliminal Stimulation
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% of the time
Weber’s Law
the principle that, to be perceived as different, two stimuli must differ by a constant % (rather than a constant amount)
Sensory adaption
diminished sensitivity as a consequence of constant stimulation
Transduction
conversion of one form of energy to another
ex) converting sights/sounds/smells to neural impulses
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
Intensity (amplitude)
the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude
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 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 grey; 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 give rise to color sensations
Optic nerve
the nerve that carries neural impulses from the eye to the brain
*Ganglion cells are from the optic nerve
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
Feature detectors
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
*They pass on information to other cortical areas to respond complex patterns
Parallel processing
the processing of many aspects of a “problem” simultaneously (like vision)
*The brain divides a visual scene into sub dimensions, works on each aspect simultaneously, then constructs our perception by integrating the parallel parts
Young-Helmholtz trichromatic theory
the theory that the retina contains 3 different 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 colour vision
Colour deficient vision
people who suffer red-green deficiency
Audition
the sense or act of hearing
Sound
is a longitudinal wave
Amplitude
tells how loud a sound is
Frequency (pitch)
the number of complete waves that pass a point (per second)
more waves = high pitch
less waves = low pitch
Outer ear
consist of auditory canal and eardrum and pinna
they collect sound waves and start a chain reaction of vibrations
Middle ear
the chamber that contains 3 tiny bones (hammer, anvil, and stirrup) that continue the vibrations
Inner ear
the innermost part of the ear containing the cochlea, semicircular canals, and vestibular tubes.
Cochlea
a coiled bony, fluid filled tube in the inner ear through which sound waves trigger nerve impulses
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 travelling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
Two ears
to locate the origin of sounds
Conduction hearing loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
Sensorineural hearing loss
hearing loss caused by damage to cochlea’s receptor cells or to the auditory nerves; also called nerve deafness
Cochlear implants
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
Touch
“the alpha and omega of affection” - William James
Kinesthesis
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
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
Psychological influences of pain
- can be distracted from it
- forget about it
- brain can create pain
- brain edits pain memory (child birth)
Social-cultural influences of pain
we experience more pain, when others do as well
Sweet
energy source
Salty
sodium - essential to us
Sour
potentially toxic acid
Bitter
potential poisons
Umami
proteins to grow and repair tissue
Pleasing tastes
attracted our ancestors to energy or protein rich foods that enabled their survival
Adverse tastes
deterred them from new food that might be toxic
Taste
a chemical sense
taste buds have pores that catch food chemicals
Sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste
Sense of smell
receptor cells send messages to the brain’s olfactory bulb, and then on to the temporal lobe’s primary smell cortex
Gestalt
we constantly filter sensory information and infer perceptions in ways that makes sense to us
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 constant groups
Proximity
we group nearby figures together
Similarity
we group similar figures together
Continuity
we perceive smooth continuous patterns, (not choppy ones)
Connectedness
when things are uniformed and linked we see them as a single unit
Closure
we fill in gaps to complete, whole objects
Depth perception
the ability to see objects in 3 dimensions although the images that strike the retina are 2-dimensional; allows us to judge distances
Visual cliff
a laboratory device for testing depth perception in infants and young animals
Binocular cues
depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal disparity
a binocular cue for perceiving depth: By comparing images from the retinas in the two eyes, the brain computes the distance - the greater the disparity (difference) between two images, the closer the object
Monocular cues
depth cues, such as interposition and linear perspective, available to either eye alone
Motion perception
normally your brain computes motion based on the assumption that shrinking objects are retreating and enlarging objects are approaching
Phi phenomenon
an illusion of movement created when two or more adjacent lights blink on and off in quick succesion
Perceptual constancy
perceiving objects as unchanging, even as illumination and retina images change
Horizon cues
make it look farther away, therefore larger
Color constancy
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Sensory deprivation
cuts a person off from as many sensory inputs as possible.
Restored vision
Someone who doesn’t have sight can’t remember seeing, then has their vision restored, lacks schemas and absence of sensory and perceptual development.
Perceptual adaptation
in vision, the ability to adjust to an artificially displaced or even inverted visual field
Perceptual set
a mental predisposition to perceive one thing and not another
Extrasensory perception (ESP)
the controversial claim that perception can occur from sensory input; includes telepathy, clairvoyance, and precognition
Telepathy
mind to mind communication
Clairvoyance
perceiving remote events
Precognition
perceiving future events
Parapsychology
the study of paranormal phenomena, including ESP and psychokinesis
