Signal detection is a method used to identify and differentiate between meaningful signals and background noise in various fields, such as psychology, telecommunications, and radar technology. It involves analyzing data to determine whether a specific signal is present or absent, often using statistical techniques to improve accuracy. In psychology, Signal Detection Theory helps researchers understand how people make decisions under uncertainty. It considers factors like sensitivity to signals and decision-making criteria, allowing for a better understanding of how individuals perceive stimuli in environments filled with distractions or competing information.