In signal detection theory, threshold responses depend on an internal response criterion reflecting bias.

Evidence

The listener has to determine, based on the internal response alone, whether the signal was presented. Here, the listener only has access to the internal response, but we assume that familiarization and learning over multiple trials allow the listener to learn the patterns of activity associated with the signal-absent and signal-present distributions. The theory assumes that the listener establishes a criterion, or an amount of internal response above which he will answer, “Yes I heard a signal” and below which he will answer, “No I did not hear a signal.” The criterion reflects the response bias of the listener, the tendency to say, “Yes I heard a signal.” — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 332

Categorization

• DEFINE: Introduces the criterion concept that separates sensitivity from response bias.