lecture 4 motion perception and action

Question 1

briefly describe Gibson’s theory of direct perception?

Answer 1

> visual perception is not just about object identification
perception and action are closely intertwined
an ecological approach of perception
information pickup from the ambient optic array
light reaching the eye provides unambiguous information about object layout, NOT MUCH INFORMATION PROCESSING.
he tried to understand visual perception in the real world.

Question 2

optic flow?

Answer 2

changes in patterns of light,everything moves except for the point of fixation.

Question 3

What is important in Gibson’s theory ?

Answer 3

is the perception of affordances

Question 4

what are perception of affordances?

Answer 4

potential uses of objects, Gibson - these are perceived directly / automatically ( eg: if you perceive a hammer you will associate it with the action of hammering)

Question 5

what are affordances?

Answer 5

properties of objects which show users the actions they can take, affordances are key to users desired actions.

Question 6

explain tucker&ellis 1998 perception of affordances?

Answer 6

> evidence for the notion that affordances are perceived directly comes from tucker and ellis study.
question: is the object upright or upside down.
quicker when handle is pointing to the right side
in conclusion = the present study provides evidence consistent with the view that the actions afforded by a visual object are INTRINSIC to its representations.

Question 7

why were the results of the tucker and ellis 1998 study criticized?

Answer 7

criticized for having confounding stimuli > if you put a stimulus on the right side of the screen you are quicker to respond to it with your right hand.

Question 8

what did wilf et al 2013 study?

Answer 8

conducted a good experiment and well controlled to test both the graspability and compatibility of objects.
> they took EMG’s and RT’s
> their results suggest that graspable objects activate the motor system in a general, body-part independent fashion.

Question 9

describe the Glover, 2004 planning-control model?

Answer 9

planning system = active before initiation of movement
control system = active during execution planned action.
all of this information comes together in the INFERIOR PARIETAL LOBE (MODULE) - where planning and control takes place based on the information that is coming from all the sources available.

Question 10

briefly describe “planning”?

Answer 10

> the spatial characteristics of the actor and the target (size, shape, spatial relations)
the non-spatial characteristics of the target (weight, fragility, friction)
the overarching goal(s) of the action (eg: picking up a cup to put it away or fill it up)
the visual context surrounding the target.
RELIANCE ON MEMORY ( AND THUS, MANY MORE BRAIN AREAS)

Question 11

briefly describe the “control system”?

Answer 11

execution of planned action
> ensure curacy of movements (proprioceptive feedback for this)
> influenced by spatial characteristics of environment
> relatively fast
>decays RELATIVELY FAST (does not stay long in memory)

Question 12

identify evidence for the planning-control model?

Answer 12

Patient DF: ventral damage
> Inferior temporal cortex impaired (identity stored here, identify objects ect)
> severe problems with object recognition
> also impairment in motor planning
> not enough information going into the inferior parietal lobe
2) optic ataxia
> damage to superior parietal lobe (SPL)
> initial movements can be correct (plan actions well)
> poor adjustments of movement
> lack of control over movements
> planning is relatively intact

Question 13

identify evidence for planning-control model from neuroimaging?

Answer 13

CHECK SLIDES DIAGRAM