The speed of response to synthesized voice messages

The experiment evaluates the effectiveness of synthesized cockpit voice warning messages using measures of reaction time (RT). Research has shown that voice messages are comparable to audio warnings and that synthesized voice messages are easily recognizable at low signal to noise ratios. This study evaluates synthesized voice messages are easily recognizable at low signal to noise ratios. This study evaluates synthesized voice messages by observing their performance in combination with auditory and visual indicators. Four different warning arrangements were used of which three had a Votrax voice component. The four warning systems represented future possible warning combinations for transport aircraft. Subjects had to deal with simulated emergencies whilst performing a psychomotor tracking task and monitoring ATC messages. Thirty commercial pilots took part in the study. Overall the four warning systems were equally effective in terms of RT. However, voice messages had significantly slower RTs than audio warnings. Voice messages and illuminated legends caused significantly less disruption of ATC monitoring than audio warnings. Pilots also consistently cross-checked voice and audio inputs with visual indicators. It is suggested that the proliferation of cockpit voice inputs should be avoided until human factor evaluations of simpler but equally effective warning systems have been completed.