Chapter 7/8 Flashcards
Determines how movement creates perceptual information that helps people move within the environment
Ecological approach to perception
movement of an observer creates movement of objects and the scene relative to the observer.
optic flow
the different speed of flow- fast near the observer and slower farther away. Provides information about how fast the observer is moving.
gradient of flow
the absence of flow at the destination point. The stationary points in the center of the horizon, from which all points, and the perspective image seem to emanate.
focus of expansion (FOE)
information that remains constant regardless of what the observer is doing or how the observer is moving.
invariant information
aka “motion blindness”. A condition in which motion is either very difficult or impossible to perceive.
akinetopsia
the point in time when an event ends and the next one begins
event boundary
created by placing small lights on people’s joints and then filming the patterns created by these lights when people move.
point-light walkers
the physical stimulus is actually moving and we perceive it as moving.
real motion
the perception of the motion of stimuli that aren’t actually moving.
illusory motion
when two stimuli in slightly different locations are alternated with the correct timing, an observer perceives one stimulus moving back and forth smoothly between the two locations.
apparent motion
when motion of one object (usually a large one) causes a nearby stationary object (usually smaller) to appear to move.
induced motion
when viewing a moving stimulus causes a stationary stimulus to appear to move.
motion aftereffects
if you look at a waterfall for 30 to 60 seconds and then look off to the side at part of the scene that is stationary, you’ll see everything you’re looking at- rocks, trees, grass- appears to move upward for a few seconds.
waterfall illusion
the structure created by the surfaces, textures, and contours of the environment.
optic array
Occurs when one object moves relative to the environment, so that the stationary background is covered and uncovered by the moving object.
local disturbance in the optic array
everything moves at once in response to movement of the observers eyes or body.
global optic flow
hypothetical neural circuits postulated for how the brain can track motion.
Reichardt detector
compares the signals it receives from neurons A and B. Also multiplies the responses from A&B to create the movement signal that results in the perception of motion.
output unit
slows down the signals from A as they travel toward the output unit.
delay unit
contains mainly directionally selective neurons. A specialized area for processing information about motion.
middle temporal (MT) area
indicates the degree to which a stimulus moves in the same direction.
coherence
a method that temporarily disrupts the normal functioning of neurons.
transcranial magnetic stimulation (TMS)
achieved by lowering a small wire electrode into the cortex and passing a weak electrical charge through the tip of the electrode. This weak shock stimulates neurons that are near the electrode tip and causes them to fire, just as they would if they were being stimulated by chemical neurotransmitters released from other neurons.
microstimulation
a situation in which the neurons receptive field is functioning like an aperture, which reveals only a small portion of a scene.
aperture problem
apparent movement tends to occur along the shortest path between 2 stimuli.
shortest path constraint
self-produced motion of a person or other living organism.
biological motion
