Date Thesis Awarded


Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)




Peter Vishton

Committee Members

Christopher Ball

Mainak Patel


Researchers have long observed different illusion magnitudes in verbal response tasks and visually-directed action tasks. The cause of such differences has been the topic of debate. The “two visual systems hypothesis” (TVSH) suggests that two separate visual pathways independently control a certain type of tasks. According to this theory, the difference in illusion magnitudes is caused by the different performance of these two pathways. An alternative theory is the “two modes of processing” (TMOP) hypothesis, which states that the two visual processing modes function within a single visual pathway but weigh the same set of visual information differently. According to this theory, the drop of illusion magnitudes in visually-directed action tasks is the result of such different weights. The three experiments presented here focus on the effect of motion parallax and binocular depth cues, haptic feedback from 3D target disks, and body postures, respectively. Results suggest that while haptic feedback and body postures are critical to the reduction in illusion magnitudes, motion parallax and binocular depth cues seem to be irrelevant. Limitations and future directions are suggested.

On-Campus Access Only