Document Type


Degree Name

Master of Science (MSc)



Program Name/Specialization

Cognitive Neuroscience


Faculty of Science

First Advisor

Dr. Jeffery Jones

Advisor Role

Thesis Supervisor


The purpose of the following study was to investigate the long-term effects of cannabis use on attention to motion.

Methods: Cannabis users, who varied in age of onset of use, were compared to control participants after abstaining from cannabis for at least 24 hours. One-hundred and ninety-seven participants engaged in a cognitive assessment followed by a motion discrimination task and an attention to motion task. The assessment consisted of a series of standard tasks that measured a range of cognitive processes such as attention, memory, and executive functioning. The motion discrimination task assessed the participants’ abilities in discriminating between various motion types: horizontal, vertical, and radial motion. The attention to motion task assessed the participants’ sensitivity to attending to target moving stimuli that varied in coherence.

Results: Controls did not perform significantly better overall on the cognitive assessment than cannabis users. Furthermore, no significant differences in motion coherence thresholds were found between controls and cannabis users; however, radial motion had higher thresholds compared to translational motion. No significant differences were observed between controls and cannabis users in terms of motion sensitivity scores. Frequency of use, abstinence duration and duration of use did not have a significant effect on motion sensitivity either.

Conclusions: Abstinent cannabis users performed just as well as controls overall in the cognitive assessment. Age of onset, frequency of use, duration of use, and abstinence duration do not appear to have a significant effect on one’s ability to attend to moving stimuli.

Convocation Year