psychophysics
metods that measure the streangth of a stimulus and the observe's sensitivity to that stimulus
absolute threshold
the minimal intensity needed to just barely detect a stimulus
synesthesia
a perceptual experience of one sense that is evoked by another sense
sensation
simple stimulation of the sense organ
perception
the organization, identification and interpretation of a sensation in order to forma amental representation
transduction
what takes place when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
signal detection theory
an observation that the response to a stimulus depends both on a person's sensitivity to the stimulus in the presence of noise and on a person's response criteria
just noticeable difference
the minimal change in a a stimulus that can just barely be detected
Weber's law
the just noticeable difference of a stimulus is a constant proportion despite variations in intensity
sensory adaptation
sensitivity to prolonged stimulation tends to decline overtime as an organism adapts to current condition
visual acuity
the ability to see fine detail
retina
light-sensitive tissue lineing tha back of the eyeball
accommodation
the process by which the eye maintains a clear mage on the retina
cones
photoreceptors that detect color operate under normal daylight conditions for night vision
fovea
an area of the retina where vision is the clearest and there are no rods at all
rods
photoreceptors that become active under low light conditions for night vision
blind spot
a location in the visual field that produces no sensation on the retina because the corresponding area of the retina contains neither rods nor cones
receptive field
the region of the sensory surface that, when stimulated, causes a change in the firing rate of the neuron
trichromatic color representation
the pattern of responding across the three types of cones that provides a unique code for each color
color-opponent system
pairs of visual neurons that work in opposition
area V1
the part of the occipital lobe that contains the primary visual cortex
visual-form agnosia
the inability to recognize objects by sight
binding problem
how features are linked together so that we see unified objects in our visual world rather than free-floating or miscombined features
illusory conjunction
a perceptual mistake where features from multiple objects are incorrectly combined
feature integration theory
the idea that focused attention is not required to detect the individual features that comprise a stimulus but is required to bind those individual features together
perceptual constancy
a perceptual principle stating that even as aspects of sensory signals change, perception remains consistent
simplicity
perceptual grouping rule that states that the simplest explanation is usually the best
closure
perceptual grouping rule that states that we tend to fill in missing elements of a visual scene such as gaps to complete objects
continuity
perceptual grouping rule that states that edges or contours that have the same orientation are grouped together
similarity
perceptual grouping rule that states that regions that are similar in color, lightness, shape or texture are perceived as being the same object
proximity
perceptual grouping rule that states that objects that are close together tend to be grouped together
common fate
perceptual grouping rule that states that elements of a visual image that move together are perceived as parts of a single moving object
template
a mental representation that can be directly compared to a viewed shape in the retinal image
monocular depth cues
aspects of a scene that yield information about depth when viewed with only one eye
binocular disparity
the difference in the retinal images of the two eyes that provides information about depth
apparent motion
the perception of movement as a result of alternating signals appearing in rapid succession in different locations
change blindness
when people fail to detect changes to the visual details of a scene