Table 3.

Design of Experiment 3

Group	Phase 1 (Context A)	Phase 2 (Context B)	Retention Interval (days)	Test (Context B)
Control-short	4 X→US	Context	2	X
Massed-short	4 X→US	20 X massed	2	X
Spaced-short	4 X→US	20 X spaced	2	X
Control-long	4 X→US	Context	22	X
Massed-long	4 X→US	20 X massed	22	X
Spaced-long	4 X→US	20 X spaced	22	X

Note—X was a clicker CS, and US was a footshock. Numbers next to pairings denote the number of trials. Massed groups were subdivided into subgroups that experienced trials early or late in the extinction session, which was 220 min long. The retention interval was either 2 or 22 days and was spent in the home cages.