Table 1.

Physical force requirements across the three pooled effort discounting studies.

Study	n	Force requirement (Levels 1–6; % MVC)	Trial duration (s)	Number of trials
				Reinforcement phase	Choice phase
1	34	5, 10, 15, 20, 25, 30	5	60	100
2	29	4, 12, 20, 28, 36, 44	10	60	75
3	40			18	75