Chapter 4: Sensation & Perception Flashcards
What is bottom-up processing?
using small components and building up
What is top-down processing?
using the larger components and breaking down (guided by experience and expectations)
Perception
influenced by both the raw sensory data that’s coming in, the bottom-up processing, but also the top-down processing, which is where your goals, your schemas, your experiences shape that perception
Sensation
process through which senses detect visual, auditory, and other sensory stimuli and transmit them to the brain
What are the four attributes common to all senses?
transduction, sensory adaptation, receptive fields, and thresholds
What is transduction?
process through which sense receptors transform physical stimulation into neural impulses
What is sensory adaptation?
the process of becoming less sensitive to unchanging sensory stimulation over time
What are receptive fields?
region of space where stimuli affect the activity of a cell in a sensory system
What is two-point discrimination (2PD)?
the ability to discern that two nearby objects touching the skin are truly two distinct points
Which of the four attributes is responsible for the way the brain filters out large quantities of sensory information?
sensory adaptation
Absolute threshold
the lowest percentage you can detect a stimulus half the time
What does it mean when a stimulus is below threshold?
it is detected fewer than 50% of the time
What is psychophysics?
study of stimulus and the brain’s response
What is the difference threshold?
the smallest physical difference between two stimuli that can still be recognized as a difference. Also known as the Just Noticeable Difference (JND)
Weber’s fraction
smallest change in the magnitude of a stimulus that can be detected expressed as a proportion to the original stimulus. Calculated as delta I/I =k
Signal detection theory
determines that sensation is not just a yes/no
What are the four outcomes as determined by the signal detection theory?
hit, false alarm, miss, and correct rejection
What is a hit?
there was a signal and it was detected
What is a false alarm?
thought there was a signal, but there wasn’t
What is a miss?
there was a signal that wasn’t detected
What is a correct rejection?
decided there was no signal and are correct
What is the sclera?
the mostly white part of the eye that provides protection and structure to the eye
What is the cornea?
the membrane that goes around the outside of your eye, which protects the eye and bends incoming light waves
What is the iris?
the ring-shaped pigmented muscle tissue in the eye, which changes pupil size to regulate the amount of light that enters your eye
What is the function of the lens in the eye?
to focus light in your retina, and change shape depending on how far away an object is
When an object is closer to your face, your lens becomes _____
rounder
When an object gets farther away, your lens becomes _____
flatter
What is the vitreous humor?
a clear, jelly-like substance that helps to cushion the eyes
What do the rods detect?
variations in dark and light changes
What do the cones detect?
blue, red, and green wavelengths of light
What is the fovea?
the point of central focus in the eye, where cones are concentrated
What type of cells form the optic nerve?
ganglion cells
What is the blind spot?
the area where no sensory information is received
Where is the visual cortex located?
the back of the brain
What are the two types of visual pathways?
the contralateral visual pathway and the ipsilateral visual pathway
How do visual pathways work?
when we have light coming in from our left visual field that information is going to the inside of our left eye and the outside of our right eye, and vice versa
What is the contralateral visual pathway?
when information crosses over to the opposite visual cortex
What is the ipsilateral visual pathway?
when information goes straight back to the visual cortex
What are the three dimensions of color vision?
hue, saturation, and brightness
What is hue?
specific color perceived, determined by wavelength of light
What is saturation?
the purity of a color, determined by the number of wavelengths that make up the light
What is brightness?
intensity of color, determined by wave amplitude
What are the two types of color mixing?
additive and subtractive
What is additive color mixing?
creating a new color by mixing different wavelengths (light)
What is subtractive color mixing?
creating a new color by removing wavelengths from a light with a broad spectrum of wavelengths (mixing paints, dyes, or pigments)
What are the two theories of color vision?
trichromatic theory and opponent-process theory
Trichromatic theory
eye is receptive to three colors, cones respond to blue, green, and red wavelengths
Opponent-process theory
three types of visual receptors, each sensitive to a pair of complimentary or opponent colors: red/green, yellow/blue, and white/black
What is an afterimage?
a visual sensation that remains after a stimulus has been removed
What is color blindness?
the inability to distinguish some colors (or in rare cases, all colors)
What is normal vision?
occurs when light is focused directly on the retina rather than in front or behind it
What is nearsightedness?
visual image is focused in front of the retina
What is farsightedness?
visual image is focused behind the retina
What is the outer ear: ipinna?
the external flap of skin and cartilage in your outer ear that collects sound waves
What is the eardrum?
an oval-shaped membrane in the middle ear that vibrates when a sound wave reaches it
What are the ossicles?
hammer, anvil, and stirrup
What is the function of the ossicles?
to intensify eardrum vibration
What is the oval window?
area where the vibrations are picked up by the eardrum and passed on to the inner ear
What is the cochlea?
snail-shaped membrane that contains hair receptor cells for hearing (cilia) located in the inner ear
What is the basilar membrane?
the lining on the inside of the cochlea where the cilia are located
What is frequency?
number of cycles completed by a sound wave in 1 second; pitch
What is amplitude?
the height of a wave, determines the loudness of sound
What is timber?
the complexity and quality of a sound
What is the olfactory epithelium?
a mucous membrane that holds the receptors for smell
How long is the life cycle for olfactory neural receptors?
approximately 30 days
What is one of the major senses that does not need to go through the thalamus in order to send a signal?
smell
