On the Performance of a Combination of Detectors

The performance of a combination of two hypothetical detectors is first examined. It is shown that the performance of the combination may be as poor as the poorer detector alone when the inflation in false alarm rate of the combination of detectors is considered. Experimental tests were carried out in which listeners attempted to detect the presence or absence of a tonal signal in noise under two conditions: unaided by an external source of information (actually aided by a simulated machine detector set at chance performance); and aided by a simulated machine detector set at the same discriminability as the listener. While the performance of the aided listener was consistently superior to the unaided listener, the improvement in performance fell considerably short of an ideal combination. It is concluded that the gain in performance expected from combinations of detectors must be interpreted cautiously.