Date of Award


Degree Type


Degree Name

Master of Science




Dr. Melvyn Goodale

Second Advisor

Dr. Daniel Ansari

Third Advisor

Dr. Stefan Köhler


We developed a rapid reaching paradigm in which we require participants to make speeded reaches toward ambiguous target displays, with a goal target filling-in only after movement onset. In our previous work, we have found that initial reaches extend toward the averaged spatial location of the presented targets. Our aim for the current study was to determine if object connectedness - a strong perceptual illusion in which two connected objects appear as one - could influence the strategic reaching behaviour. Even though there was a powerful effect of the illusion on perception, the visuomotor system was able to utilize the true target information and continue to plan reaches based on the number and distribution of targets presented. These results resonate with the idea of a division of labour between vision-for-perception and vision-for-action - but extend this dissociation (with respect to the action system) into the realm of motor planning.



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