Signaalintunnistus

Signaalintunnistus, also known as signal detection theory, is a framework for studying how people make decisions in ambiguous situations. It is used to understand how observers detect signals from noise. The theory was originally developed by statistical theorists and engineers to help engineers distinguish between signals and noise in electronic systems. However, it has since been applied to a wide range of fields, including psychology, neuroscience, and medicine.

In signal detection theory, the observer is presented with a series of stimuli. Some of these stimuli are signals, and others are noise. The observer must decide whether each stimulus is a signal or noise. There are four possible outcomes for each stimulus: a hit, a miss, a false alarm, or a correct rejection. A hit occurs when the observer correctly identifies a signal as a signal. A miss occurs when the observer fails to identify a signal as a signal. A false alarm occurs when the observer incorrectly identifies noise as a signal. A correct rejection occurs when the observer correctly identifies noise as noise.

The theory proposes that the observer's performance can be described by two parameters: sensitivity and response bias. Sensitivity refers to the observer's ability to discriminate between signals and noise. Response bias refers to the observer's tendency to say "yes" or "no" to a stimulus. Sensitivity is independent of response bias. This means that an observer can be highly sensitive to signals but still have a strong bias to say "yes" or "no".

Signal detection theory has been used to study a variety of phenomena, including visual perception, auditory perception, and memory. It has also been used to study the performance of diagnostic tests, such as those used to detect cancer. The theory has provided a powerful tool for understanding how people make decisions in uncertain environments.