Dissociation or integration: Early Illusion evidence Flashcards
(16 cards)
True or false, the dual stream hypothesis would suggest that illusions would still affect actions
False - illusions = failures of perception, so actions should be free from effect of illusions
Aglioti et al (1995) study is based on the idea that actions are mediated by the ________ stream, with _______________ visumotor control, therefore less influenced by ______________ cues, such as the ________________ circles of an ______________ illusion.
actions mediated by dorsal, with egocentric visuomotor control, and less influenced by allocentric cues - such as the neighboring circles on an Ebbinghaus illusion.
Summarize the main two findings by Aglioti et al 1995?
Ebbinghaus illusion strongly affected perceptual judgements in perceptual matching task- viewing circle as larger when in reality the same size.
Actions - grip aperture when grasping the circle (3d poker chip) was resistant to illusions, largely determined by objecrs true physical size
Otto-de-haart (1999) found a similar effect to Aglioti where actions were resistant to illusions but using what illusion?
Muller-Lyer Illusion
What illusion was used by Brenner and Smeets in 1995 to test if action was affected by illusions?
Ponzo illusion
How much larger did participants judge the perceived larger disk to be on the ponzo illusion (Brenner and Smeets, 1996)?
0.8mm
Brenner and Smeets found that illusion did not affect ________ _________, likely mediated by ___________ perception cues of the ________object size. The illusion did affect ________ to _________ the object, likely affected by ____________ object size, under influence of illusion.
Illusion did not affect grip size - mediated by egocentric cues based on real object size.
Illusion did affect grip force/velocity when lifting - affected by perception of object, therefore affected by illusions
How did Brenner and Smeets actually measure force/lifing?
They did not measure grip force directly instead through timing - how quickly velocity increased is indicative of force - quicker = more force
What did Franz et al (2000) propose was the true difference behind illusion effects on action and perception?
Rather than a true dissociation between vision for action and for perception where actions are unaffected by illusions, differences in findings are due to action and perception tasks not being comparable
True or false, in illusion studies, such as Aglioti, illusion had no affect on action at all.
False - illusion did have an effect on action but smaller than that of perception, and more variable.
What were the three main differences between action and perception tasks in Aglioti’s study, which Franz et al criticised, and then improved upon?
In perception, used 2D visual array, in action , used 3D poker chip - should use 3D for both
In perception task was a comparison, but in action task was to grasp only one - Franz made both tasks non-comparisons
Perception and action tasks not comparable - perception = verbal judgement, whereas action task allows visual feedback.
After removing visual feedback in action tasks, what did Franz et al (2000) find?
After removing visual feedback
What is one main caveat to Franz et al presenting the parts of the Ebbinghaus illusion one at a time?
Takes away the effect of the illusion - whole point of illusion is to compare
Post and Welch (1996) found that actions are susceptible to illusions only when ___________________________________________. When there is a ________ ___________ to give __________, actions are much less affected and more reliant on _____________ visuomotor control.
Actions susceptible only when relying on internal visual representations.
When there is a visible marker/midpoint, actions are much less affected and reliant on egocentric vision.
In Carey’s (2001) review paper what are his two main arguments?
Does criticise some illusion studies such as Aglioti for not properly matching tasks
Argues that some more simple actions are less influenced by illusions - such as grip aperture, mainly in the realm of motor control and some actions are more influenced - wight judgements, influenced by perception.
Goodale and Westwood (2014) argued that illusions have less of an impact an actions which can be guided by ________ _______ _________ ___________
Illusions do not affect actions which have real time visual feedback - gripping an object.
