Handbook of Item Response Theory

A large part of cognitive psychological research operates under the assumption that the time it takes to complete a task (e.g., taking a decision) carries information on how the task is solved. The earliest use of response time (RT) in scientific psychological research can be traced back to the late nineteenth century (e.g., Donders, 1869/1969). In fact, since then, RT has probably been the most important dependent variable used in cognitive psychology.