Signal Detection Theory The theory of signal detection theory
evolved from the development of communications and radar
equipment the first half of this century. It migrated to
psychology, initially as part of sensation and perception, in
the 50's and 60's as an attempt to understand some of the
features of human behavior when detecting very faint stimuli
that were not being explained by traditional theories of
thresholds. The situation of interest is this: What makes this
different from traditional threshold theories is that the
subject makes a decision, a cognitive act, as to whether the
signal is present or not. This basic sensory act of determining
if a stimulus occurred now is understood to have a cognitive
component. If you want a concrete example, click here. Now what
can happen in this situation. If the signal is present the
person can decide that it is present or absent. These outcomes
are called hits and misses. If the signal is absent the person
can still decide that the signal is either present or