["Journal of the Experimental Analysis of Behavior, Volume 125, Issue 3, May 2026. ", "\nAbstract\nThe behavioral theory of timing (BeT), developed by Killeen and Fetterman in 1988, accounts for the performance of animals on many timing tasks using sequences of adjunctive behaviors rather than internal clocks and related cognitive mechanisms as its explanatory principle. The idea that timing was mediated by behavior or, perhaps more correctly, sensations arising from behavior, was in fact proposed in the 19th century by Munsterberg. The article describes some of Munsterberg's work and research that followed it, notably Curtis's extensive study from 1916 of “strains and relaxations” experienced by her participants while they performed a variety of time judgement tasks. An unresolved question both for BeT and the earlier work is deciding whether the behaviors observed, which are found to occur reliably, are necessary for timing tasks to be carried out or are epiphenomenal to other underlying timing mechanisms.\n"]