chapter 5 Perception
form perception: what is it?
the importance of features
feature detectors: one of these cells might fire if a particular angle is in view; another might fire if a
vertical line in is veiw, and so on.
Gestalt psychology: a theorectical approach that emphasizes the role of organized wholes in perception
and other psychological processes.
parse: how you seperate a scene into individual objects, linking together the parts of each object but not
linking one object's parts to some other object.
similarity: in perception, a priniciple by which we tend to group like figures, especially by color and
proximity: in perception, the closeness of two figures. the closer together they are, the more we tend to
group them together.
good continuation: a factor in visual grouping; we tend to percieve contours in a way that alters their
direction as little as possible.
subjective contours: percieved contours that do not exist phsyically. we tend to complete figures that
have gaps in them by percieving a contour as continuing along its original path.
figure and ground
reversible figure: a visual pattern that easily allows more than one interpretation, in some cases
changing the specification of figure and ground, in other cases changing the percieved organization in
network models of preception
visual search: a task in which participants are asked to determine whether a specific target is present
within a field of stimuli.
feature net: a model of pattern recognition involving a network of detectors and having feature
detectors as the network's starting point.
from features to geons to meaning geons: (geometric ions): simple geometric figures, such as cubes, cylinders and pyramids, that can be
combined to create all other shapes. An early and crucial step in some models of object recognition in
determining which geons are present.
neuroscience of vision
the visual pathway
parvo cells: ganglion cells that, because of their sensitivity to differences in hue, are particularly suited
to percieving color and form.
mango cells: ganglion cells that, because of their sensitivity to brightness changes, are particularly
suited to percieving motion and depth.
the "what" and "where" systems
"what" system: the visual pathway leading from the visual cortex to the temporal lobe; especially
involved in identifying objects.
"where" system: the visual pathway leading from the visual cortex to the parietal lobe; especially
involved in locating objects in space and coordinating movements.
the binding problem
binding problem: the problem confronted by the brain of recombining the elements of a stimulus,
given the fact that these elements are initially analyzed separately by different neural systems.
neural synchrony: different groups of neurons firing in synchrony with each other, to identify which
sensory elements belong with which.
perceptual constancy: the accurate perception of certain attributes of a distal object, such as its shape,
size, and brightness, despite changes in the proximal stimulus caused by variations in out viewing