Table 1. The first session at which the stability criterion was satisfied for each participant at each concurrent VI VI pair. Response rates were deemed stable across the eight sessions before and including the session indicated below. For each concurrent pair, data were averaged across the eight sessions before and including the session indicated below.

Participant	Schedule A magnitude	Concurrent VI VI schedules
		VI 17 – VI 720	VI 25 – VI 300	VI 51 – VI 51	VI 300 – VI 25	VI 720 – VI 17
H59	$0.2	15	15	11	15	12
	$0.12	12	13	11	11	13
	$0.07	11	12	13	11	11
	$0.004	11	11	19	19	11
	$0.0025	11	11	14	20	20
H60	$0.2	12	11	11	11	11
	$0.12	13	11	16	11	11
	$0.07	11	11	11	16	11
	$0.004	11	11	11	11	11
	$0.0025	12	11	14	14	11
H64	$0.2	11	13	11	13	12
	$0.12	11	11	16	11	11
	$0.07	13	11	12	13	11
	$0.004	18	12	14	12	11
	$0.0025	12	13	11	21	12
H67	$0.2	11	11	11	14	16
	$0.12	11	14	13	14	11
	$0.07	11	11	11	11	11
	$0.004	12	12	12	11	11
	$0.0025	12	11	18	15	11
H69	$0.2	11	12	11	16	11
	$0.12	13	11	11	16	16
	$0.07	12	11	11	11	16
	$0.004	13	12	11	11	13
	$0.0025	11	12	11	18	12
H70	$0.2	11	13	22	12	12
	$0.12	13	13	14	12	14
	$0.07	11	11	13	13	11
	$0.004	11	11	18	11	11
	$0.0025	11	17	19	11	12