Differential Base Rate Training Influences Detection of Novel Targets in a Complex Visual Inspection Task

We studied the effects that multiple levels of signal probability (known as base rate) have on the transfer of learning in an airline luggage screening task. Participants (n = 33) were presented with three base rates during the acquisition (training) phase: 100%, 50%, or 20%; at transfer, all participants detected novel targets at a base rate of 20%. Performance was measured by hit rates, false alarm rates, sensitivities, and detection times. Results revealed that participants receiving higher base rates during training obtained higher hit rates at transfer compared to participants encountering lower base rates. However, increasing the training base rate also increased the incidence of false alarms, leading to a low overall level of sensitivity during transfer. Relatively higher base rates had mixed effects on response times. These results have implications for improving training modules for individuals in complex visual inspection tasks.