Vigilance for Auditory Intensity Changes as a Function of Preliminary Feedback and Confidence Level

Forty-eight subjects were asked to respond to occasional increments in a pulse train with ratings of certainty of signal occurrence for 20 min. Half (F) subjects were given feedback; half (NF) were not. In a second session all responded during an 80 min period with a simple response. In another, half responded with certainty ratings; half responded with a simple response. Finally, those who had responded with ratings responded simply and those who had employed a simple response made ratings. It was found that F subjects made fewer false responses and tended to make fewer detections in earlier sessions. In later sessions false responses were reduced for all. The usual progressive false response and detection reductions and latency increases were noted; when subjects employed ratings reductions in certainty were noted within sessions. It was concluded that the data support the detection theory model for vigilance for this type of task.