Glossary

An overall measure of performance defined as the proportion of all responses that are correct responses as opposed to error responses.

A sequence of trials in a psychology experiment. A typical design of such an experiment is to have one or more experimental sessions, each of which consist of one or more blocks, each of which consist of many trials. Some factors may be varied within each block, while others may be varied across blocks.

The outcome that occurs when the response that is made is the one that should have been made given the definition of the task. In a signal detection task, this occurs when the signal is present and the participant responds ‘present’ or the signal is absent and they respond ‘absent’.

The selection of an action (or lack thereof) in a particular circumstance. Or even more broadly, “a commitment to a course of action that is intended to yield results that are satisfying for specified individuals” (Yates & Tschirhart, 2006). In a signal detection task, it is the process that leads on each trial from the stimulus, which might have a signal present or absent, to a response, which might be ‘present’ or ‘absent’, or to no response.

The outcome that occurs when the response that is made is not the one that should have been made given the definition of the task. In a signal detection task, this occurs when the signal is present and the participant responds ‘absent’ or the signal is absent and they respond ‘present’.

A symbol presented to a participant on a display to act as a target for their attention before a substantive cue or stimulus is presented. Often used before the start of a trial to help prepare the participant.

The time between the end of one trial and the start of the next trial in a block of trials in a psychology experiment.

In this context, a quantitative specification, based on a particular theory, of how stimulus and response are linked via an intervening set of cognitive processes. Whereas a theory tends to be a more general explanation of a cognitive process, a model is a specific application to a particular situation or task. Signal detection theory can be applied to model a wide variety of different signal detection tasks. It is specified as a mathematical model, as opposed to a symbolic or computational model. Note that the distinctions between theories and models, and between mathematical and computational models, are fuzzy, contested, and philosophically charged.

The result of taking a particular action in a particular situation. In the context of signal detection theory, it typically refers to the four possible combinations of stimulus (present or absent) and response (‘present’ or ‘absent’): hits, misses, correct rejections, and false alarms.

An action taken as a result of the presentation of a stimulus. In a signal detection task, it is typically either ‘present’ or ‘absent’ to indicate whether the participant thinks the signal was present or absent.

In general, anything that causes a sensory and/or perceptual response. In the context of a signal detection experiment, the combination of signal and/or noise presented to the participant on each trial.

What a participant does in a typical cognitive psychology experiment. It typically consists of one or more sessions, each consisting of one or more blocks, each consisting of many trials. On each trial, there is typically a sequence of events, including one or more stimuli, and one or more responses.

In this context, a proposed explanation for how one or more cognitive processes work. Theories can be more or less precise in their specification, which can make them hard to evaluate. One approach to address this is to implement quantitative models based on the theory. (See the entry for model for more discussion.)

A single unit in an experimental task. In a signal detection task, this typically consists of a stimulus with a signal present or absent, followed by a response of either ‘present’ or ‘absent’, possibly followed by feedback such as the outcome and/or incentive. Within a block, the next trial then starts after an inter-trial interval.