Topic 7: Perception and Action Flashcards
(41 cards)
Ecological Approach to Perception
this approach focuses on specifying the information in the environment that is used for perception, emphasizing the study of moving observers to determine how their movements results in perceptual information that both creates perception and guides further movement
Optic Flow
the flow of stimuli in the environment that occurs when an observer moves relative to the environment
forward movement causes an expanding optic flow, whereas backward movement causes a contracting optic flow
some researchers use the term optic flow field to refer to this flow
Gradient of Flow
in an optic flow pattern, a gradient is created by movement of an observer through the environment
the “gradient” refers to the fact that the optic flow is rapid in the foreground and becomes slower as distance from the observer increases
Focus of Expansion (FOE)
the point in the flow pattern caused by observer movement in which there is no expansion
according to J.J. Gibson, the focus of expansion always remains centered on the observer’s destination
Invariant Information
environmental properties that do not change as the observer moves relative to an object or scene
for example, the spacing, or texture, of the elements in a homogenous texture gradient does not change as the observer moves on the gradient
the texture of the gradient therefore supplies information for depth perception
Affordances
the information specified by a stimulus patter that indicates how the stimulus can be used
an example of an affordance would be seeing a chair as something to sit on or a flight of stairs as something to climb
Action Affordances
a response to an object that involves both its affordance (what it is for) and the action associated with it
Visual Direction Strategy
a strategy used by moving observers to reach a destination by keeping their body oriented toward the target
Spatial Updating
process by which people and animals keep track of their position within a surrounding environment when they move
Wayfinding
the process of navigating through the environment
wayfinding involves perceiving objects in the environment, remembering objects and their relation to the overall scene, and knowing when to turn and in what direction
Landmarks
object on a route that serves as a cue to indicate where to turn
a source of information for wayfinding
Cognitive Map
a mental map of the spatial layout of an area of the environment
Place Cells
neurons that fire only when an animal is in a certain place in the environment
Place Field
area of the environment within which a place cell fires
Grid Cells
cells in the entorhinal cortex that fire when an animal is in a particular place in the environment, and which have multiple place field arranged in a grid-like pattern
Parietal Reach Region (PRR)
network of areas in the parietal cortex that contains neurons that are involved in reaching behavior
Visuomotor Grip Cells
a neuron that initially responds when a specific object is seen and then also responds as a hand grasps the same object
Proprioception
the sensing of the position of the limbs
Size-Weight Illusion
erroneously predicting weight when observing two differently sized objects that have the same weight
the error occurs when the perceiver predicts that the larger object will be heavier, and therefore uses more force to lift it, causing it to be lifted higher and to feel lighter
Audiovisual Mirror Neurons
neuron that responds to actions that produce sounds
these neurons respond when a monkey performs a hand action and when it hears the sound associated with this action
Mirror Neuron System
network of neurons hypothesized to play a role in creating mirror neurons
Action-Specific Perception Hypothesis
hypothesis that people perceive their environment in terms of their ability to act on it
What are the assumptions made in the ecological approach?
emphasized evolution: natural selection has shaped our perceptual system, considered perception in the natural environment, understanding motion of observer is important
all info required for perception is available in environment (bottom-up): optic array (stimulus pattern in the environment) is highly organized
the visual scene is analyzed in terms of whole objects and surfaces, not edges, colors, etc. that comprise objects: certain characteristics of the environment are invariant: a particular relationship holds constant
perception is direct, immediate: do not require further computation/mental operations, or additional info based on inferences or experience, no top-down processing
What is optic flow?
stimulus array changes in a logical way as observer moves through the environment
