Attentional Locus and Ground Dominance in Control of Speed during Low Altitude Flight

Abstract

During simulated low-altitude flight, participants' control of speed is based on the optical flow rate projected by the ground, even when changes in altitude make this information unreliable and other sources of speed information, such as the flow rate of a cloud layer above the flight path, could help to provide more valid information (Wotring, 2008). This study examined whether this ground bias in perceiving speed could be overcome by using a secondary visual search task to manipulate the attentional focus away from the ground. A task requiring participants to visually scan for potentially-colliding planes either above or below the horizon was coupled with a speed maintenance task similar to the task used by Bennett, Flach, McEwen & Russell (2006) and Wotring, Dyre, & Behre (2008). We found that altitude disturbances induced inappropriate speed control in a similar manner independent of whether the secondary task required the attentional focus to be directed above or below the horizon. These results suggest that ground bias in speed control is robust even when attention is directed above the horizon by a secondary visual task.