Sensation and Perception 1 Flashcards
sensation
occurs when special receptors in the sense organs are activated, allowing various forms of outside stimuli to become neural signals in the brains
sense organs
eyes, ears, nose, skin, taste buds
stimuli
anything in the environment that is picked up by the senses
transduction
the process of converting outside stimuli into neural activity
sensory receptors
specialized forms of neurons stimulated by different kinds of energy eyes = light ears = vibrations touch = pressure or temperature taste and smell = chemical substances
jnd
just noticeable difference
difference threshold
smallest difference between two stimuli that is detectable 50 percent of the time
weber’s law
whatever the difference between stimuli may be, it is always a constant
need more sugar to taste it in a gallon than a cup
absolute threshold
fechner
lowest level of stimulation that a person can consciously detect 50 percent of the time the stimulation is present
subliminal stimuli
stimuli that are below the level of conscious awareness
just strong enough to activate the sensory receptors but are not strong enough for people to be consciously aware of them
subliminal perception
the process by which subliminal stimuli act upon the unconscious mind and influence bx
vicary study
show subliminal messages at theater, say people buy more, but actually fake
event related potentials
erps
used to verify existence of subliminal perception and associated learning
stimuli typically influence automatic relations rather than direct voluntary bx
habituation
way brain deals with unchanging information from the environment
lower centers of brain filter sensory information and prevent conscious attention to stimuli that don’t change
sensory adaption
process by which constant, unchanging information from sensory receptors ignored
difference between habitation and sensory adaption
habituation = sensory receptors still responding to simulation but lower centers of brain aren't sending signals from those receptors to the cortex sensory = receptor cells themselves become less responsive to unchanging stimulus and receptors no longer send signals to brain
photons
wave packets of light
specific wavelengths associated with them
einstein
three aspects to perception of light
brightness, color, and saturation
brightness
determined by amplitude of wave
higher wave = brighter light, lower wave = dimmer
color
determined by length of wave
long wavelength = red end
short wavelength = blue end
visible spectrum
portion of whole spectrum of light that is visible to the human eye
saturation
purity of the color people perceive
highly saturated = only one color
not saturated = mix of many colors
how does light enter eye
directly from source (ex. sun) or indirectly by reflecting off an object
cornea
clear membrane that covers the surface of the eye
protects eye and focuses most of light coming into eye
has fixed curvature that can be changed through techniques
photoreative keratectomy (PRK) and laster assisted in situ keratomileusis (LASIK)
procedures ophthalmologists use to remove small portions of the cornea, changing its curvature, and thus the focus in the eye
aqueous humor
after cornea
clear watery fluid that is continually replenished and supplies nourishment to eye
pupil
after aqueous humor
hole through which light from visual image enters interior of eye
exists in iris
iris
after pupil (pupil in it)
round muscle, colored part of eye
changes size of pupil to let more or less light into eye
helps focus image
lens
behind iris
flexible, visual accommodation
changes shape to focus on objects close or far away
variation in thickness allows it to project sharp image on retina
visual accommodation
lens changes shape from thick to thin, enabling it to focus on objects that are close or far away
variation in thickness allows lens to project sharp image on retina
presbyopia
disorder in which people lose ability to do visual accommodation as lens hardens through aging
myopia
nearsightedness
visual accommodation may occur but shape of eye causes focal point to fall short of retina
hyperopia
farsightedness
focus point is behind retina
vitreous humor
after lens
large open space filled with clear, jelly-like fluid
fluid nourishes eye and gives it shape