Table 1.

Sequences of trial presentation during Phase 3, Experiment 1. The stimuli were presented according to one of these four sequences. In each case, the stimuli were presented in the same order they have in each row, from left to right. (+) paired with shock; (−) presented without shock.

Conditioning reminder	Transfer probes	Conditioning probe
B1 (+), B2 (−)	C2 (−), C1 (−), D2 (−), D1 (−)	B1 (−)
B1 (+), B2 (−)	C2 (−), D1 (−), D2 (−), C1 (−)	B1 (−)
B1 (+), B2 (−)	D2 (−), D1 (−), C2 (−), C1 (−)	B1 (−)
B1 (+), B2 (−)	D2 (−), C1 (−), C2 (−), D1 (−)	B1 (−)