Date of Award

Fall 2005

Document Type

Thesis - Open Access

Degree Name

Master of Science in Human Factors & Systems


Human Factors and Systems

Committee Chair

Shawn Doherty, Ph.D.

Committee Member

Dahai Liu, Ph.D.

Committee Member

Timothy Wilson, Sc.D.


In aviation, as technology becomes more advanced and more demands are placed on the human operator, warnings have become an important part of display design. Although warnings have made a significant contribution to safety, problems still plague their design. Recent technological advances have been able to give sounds and warnings a three-dimensional quality (3D). This technology enables a person to perceive sound from any direction around the listener without having the sound physically come from that direction. Three-dimensional sounds have been shown to improve target acquisition and collision avoidance in flight (Oving & Bronkhorst, 1999), and may have other future applications as well. However, one of the main drawbacks of using 3D audio technology is the increase in front and back localization errors in which a listener may confuse the location of the warnings. Mistakes in localization may be dangerous in flight, especially when locating such hazards like air traffic.

This study compares both verbal and non-verbal warnings, which have not been previously compared in previous research. The purpose of the study is to determine whether or not altering the frequency content of auditory warning signals could affect the localization performance for forward and backward presentation of the signals. The results confirmed previous research conducted by Ehmann (2001) which found that altering the frequency content did not affect localization performance. There were differences found between warning types, which indicate that future research may need to be conducted on the difference between the warnings with respect to how they are localized.