Table 1. Summary of Study Designs.

Exp	Sample size	Schedule	N training trials per stimulus	N test trials per stimulus	Outcome
Note. Exp = experiment; FR = fixed ratio; VI = variable interval; + = appetitive outcome; − = aversive outcome.
1A	36,38	FR-1	2 vs. 33	3	Shock (−)
1B	24,24,24	FR-1	4 vs. 48 vs. 96 in 2 days	8	Noise (−)
2	43	FR-1	32 vs. 160 in 3 days	8	Points (+)
3A	33,31	VI-10	12 vs. 72 in 3 days	3	Food (+)
3B	24,27	VI-10	16 vs. 96 in 3 days	3	Food (+)