Undergraduate Honours Theses
Previous studies have observed visual motion aftereffects (MAE) following prolonged exposure to both auditory and visual stimuli. As the importance of attention for MAE perception has been debated, the present study manipulated the level of attention directed to an auditory stimulus depicting motion and assessed how attention influenced MAE strength. It was hypothesized that MAE strength would be dependent on attention to the motion stimuli. 100 participants were recruited and randomly divided into either a Diverted-Attention Condition or Control Condition. Each participant completed preliminary assessments to ensure adequate auditory calibration and familiarity with the random dot kinematogram (RDK) visual motion stimuli used in the experiment. In the main task, both conditions were exposed to the same auditory stimuli - ascending or descending musical scales with intermittent noise bursts - but given different task instructions. Participants in the Diverted-Attention Condition attended to short noise bursts and ignored the musical scales; participants in the Control Condition attended to the musical scales. Trials followed an identical procedure: (1) ascending or descending scale, (2) RDK presentation, and (3) a forced-choice judgment about the motion of the RDK. RDK motion coherence and direction were manipulated. Analyses found a significant main effect of Scale Direction and Motion Coherence, but no main effect of Condition. These results replicate prior reports of auditory-driven visual MAEs but suggest that attention might not modulate these effects. Potential explanations for these findings are explored through consideration of potential design confounds, alternative perspectives, and suggestions for future studies.
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Thesis Advisor(s): Dr. Stephen Van Hedger