Ergonomics recommendations for simultaneous and delayed presentation of visual and auditory signals

This study investigated the interaction effects of simultaneous and delayed presentations of visual and auditory signals on reaction times and response errors in a combined auditory-visual setting. The delay between visual and auditory (or auditory and visual) stimuli, and the intensity levels of the auditory signals were varied. In each trial the auditory and visual signals were presented either to the left or right of the subjects, who had to respond to the direction of signal that occurred earliest. It was found that visual stimuli tended to dominate auditory stimuli in the simultaneous presentation condition. However, this visual dominance effect was weakened with increasing intensity of the auditory signal. The visual dominance effect was also found when the two signals were presented with a small delay between them. Signal position, signal modality, signal presentation sequence and warning time were all found to affect performance. Some ergonomics recommendations based on these findings are given with the aim of improving the human–machine interface design in multi-sensory control consoles in order to enhance operator response speed and accuracy and overall system performance.