what is the signal detection theory in psychology

Signal detection theory, also known as SDT, is a concept used in psychology to measure how individuals make decisions under conditions of uncertainty. It focuses on the ability to differentiate between information-bearing patterns (signals) and random patterns that distract from the information. The theory assumes that decision-makers are active and make difficult perceptual judgments under conditions of uncertainty. It is applicable in various fields such as diagnostics, quality control, telecommunications, and psychology. In psychology, SDT is used to measure how individuals perceive stimuli under uncertain conditions, such as in foggy environments or during eyewitness identification. The theory considers the intensity of the stimuli and the psychological and physical state of the individual in determining their ability to detect the stimuli. SDT has origins in radar technology, where it was used to differentiate between different types of signals. It also has applications in technology and electronics, making it a versatile concept with broad relevance.