ecological approach to perception
traditional lab research on perception was not valid
p’s couldnt move heads
ignored interaction of perception and action
movement creates peceptual info we make use of invariant info in environment
optic flow
gradient of flow
appearance of object as observer moves past them
-difference in flow as a function of distance from observer - used for speed of motion
focus of expansion
self produced information
point in distance where there is no flow (invariant)
perception (flow) and action/movement interact
brady and laurent (backflips)
backflips can be performed by learning predetermined sequence of movements
expert gymnasts performed worse with eyes closed
experts use vision for correction and novices dont
multisensory integration
p’s placed in swinging room where floor was stationary and walls/ceiling swung back and forth
movement creates optic flow patterns
children and adults swayed back and forth in response
vision has powerful effect on balance and overrides other sense that provide feedback about body placement and posture
action-specific peception hypothesis
people perceive environment in terms of ability to act on it
better hitters see softball as bigger
using baton saw distance as shorter
parkour experts saw wall as smaller
common coding theory
actions are coded in terms of percievable effects (distal perceptual effects) they should generate
visual direction strategy
p’s walked freely while viewing virtual environment through head display (12 x 12 m)
record path as person walked toward target location
looked at obstacles and would vary offsets (l/r or far/close)
p’s turn body toward goal and away from obstacles, errors corrected by reorienting
doesnt require explicit planning and happens moment by moment
spatial updating
p’s viewed a target, closed eyes and tried to walk along 1/3 paths
start location in corner and walk near/far target, sometimes had to travel along wall
accuracy decrease with distance but still do well
able to update location with eyes closed
interaction of motor control and proprioception
landmarks
p’s naviagted maze full of landmarks
train then test (explore and navigate)
p’s looked at landmarks at end of hallway or t and l junctions
testing with all or 1/2 of landmarks available
with least fixated landmarks there was no difference when landmarks were reduced
high fixated had significant difference
cognitive maps
recording of medial temporal lobe cells while navigating
animals freely moving and record movement and single neuron
cells fire in certain locations not others
place cells
grid cells
neuron fires when animal is in one location not another
fire on regular lattice in environment
hexagon shape - will fire on certain location repeatedly but not in between
border cells
head direction cells
respond to a boundary at a particular distance and direction from animal (N side of square)
respond to when animal faces certain direction irrespective of location based on orientation
affordances
potential actions that an object offers to an organism
perceivable along with physical features
masson and bub affordances
cue for hand grasp you need to make then respond with that action (vertical or horizontal)
object prime is normal or rotated
hand cue is congruent or incongruent to prime
p’s actions were faster when object was congruent with action
same for rotated/normal orientation
fattori PPR
single unit recording of PPR
fixation, see object, turn lights off then reach for object
separate vision and action
different neurons fire for differnt grasps
mirror neurons
neurons that respond both to performance of action and perception of that action
