“…More specifically, these data suggest that, at the beginning of each trial, subjects enter either a timing state, emitting target responses generated by a timing mechanism, or they enter a nontiming state, emitting target responses randomly. Alternation between these two states may reflect a more general fluctuation in behavioral control by operant schedules (Brackney, Cheung, Neisewander, & Sanabria, 2011;Cheung, Neisewander, & Sanabria, 2012;Shull, 2004;Shull, Grimes, & Bennet, 2004;Shull, Gaynor, & Grimes, 2001, 2002Gibbon, 1995;Myerson & Miezen, 1980). Performance in FI schedules is thus likely an expression of cycling into and out of multiple behavioral states until reinforcement is obtained.…”