Psychometric curves reveal changes in bias, lapse rate, and guess rate in an online vigilance task.

When human monitors are required to detect infrequent signals among noise, they typically exhibit a decline in correct detections over time. Researchers have attributed this vigilance decrement to three alternative mechanisms: shifts in response bias, losses of sensitivity, and attentional lapses. The current study examined the extent to which changes in these mechanisms contributed to the vigilance decrement in an online monitoring task.