Theses and Dissertations Collection

Previous studies examining speed control during simulated flight through a dual planar environment with altitude changing found ground dominance to occur. Participant’s adjusted speed based on the optical flow created by the ground texture located below even when explicitly instructed to attend only to the cloud texture located above (Adamic, 2011, Wotring, 2008). This thesis sought to determine whether ground dominance of speed control occurred due to an inability of participants to inhibit attention to the ground texture or due to pre-attentional processing of the ground texture, by measuring eye movements as an indicator of attentional locus. The results suggest that ground dominance for participants instructed to attend upward resulted from attentional shifts towards the ground texture. Even though the majority of participants’ fixated on the instructed plane, there was a significant relationship between the frequency of eye fixations on the ground and the strength of the ground dominance effect. These results suggest the control of egospeed is influenced by attended rather than global optical flow.