Table 1.

Design of Experiments 1–3.

Exposure	Conditioning	Test
Experiment 1
AX	X→40s→shock	AX versus BX
BY	Y→40s→no shock	BY versus AY
Experiment 2
AX	X→40s→shock	AX versus BX
BY	Y→40s→shock	BY versus AY
Experiment 3
Group consistent
C–A C–X C–A C–X	C→shock	E–AX versus E–BX
D–B D–Y D–B D–Y	D→shock	E–BY versus E–AY
Group inconsistent
C–A C–X C–B C–Y	C→shock	E–AX versus E–BX
D–B D–Y D–A D–X	D→shock	E–BY versus E–AY

Note: A and B were localized visual stimuli (left and right jewel lights), X and Y were auditory stimuli (tone and clicker), and C, D, and E were experimental contexts; 40s indicates the interval between the presentation of X (or Y) and shock.