Table 1. Order of experimental conditions, showing the conditional probabilities of a reinforcer's being arranged on Alternative x given an immediately preceding reinforcer on that alternative, p(R_x|R_x). Because the conditional probabilities were the same on both alternatives, the arranged relative reinforcer ratio was 1:1 throughout. In Condition 8, the first reinforcers in a session were arranged by a 63-step, pseudorandom binary sequence.

Condition	p(Rx|Rx)
1	.5
2	.7
3	.2
4	.9
5	.35
6	.8
7	0
7b	.5
8	1.0
9	.7