two-alternative forced-choice task

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In signal detection theory, an experimental procedure designed to eliminate bias resulting from the observer's criterion level of sensory activation by presenting the observer with pairs of observation time intervals, only one interval in each pair containing the signal, the task being to choose the interval with the signal on each trial. The theory assumes that a particular level of sensory activation occurs in each observation interval and that the observer simply chooses the larger, and it has been shown that 76 per cent correct responses in this task equates to a d prime of 1. 2AFC abbrev.

Subjects: Psychology.

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