The effect of reference signals in a visual vigilance task.

Abstract

The effect of reference signals on performance in a visual vigilance task was studied under three conditions. Reference signals were presented on the same display as the real signals. In condition 1 (control)/ no reference signals were displayed. Subjects could demand reference signals whenever they wished in condition 2 (demand reference) . Reference signals were programmed at arbitrary times during the experiment in condition 3 (programmed reference) . Twenty-four subjects were used, eight in each condition. Neither the display of reference signals upon demand nor the programmed display of reference signals significantly affected the overall level of performance. However, after activation of the reference signal sequence in condition 2 (demand reference) , there was a significant short-term improvement in performance. No significant change in the rate of commissive errors was found. All three groups showed a significant deterioration of performance over time during the experiment.