Table 1.

Experimental parameters.

	Stimulus duration	Manipulation	Shock occurrence	Shock type	Task duration
Study 1	300–700 ms	threat-of-shock (unpredictable)	immediately after response	train (3 s)	40 min
Study 2	1400–2,600 ms	threat-of-shock (unpredictable)	during ITI	train (2 s)	20 min
Study 3	1,400–2,600 ms	threat-of-shock (unpredictable)	no shock delivered	no shock	10 min
Study 4	1,400–2,600 ms	fear (predictable)	after stimulus disappeared	single pulse	10 min
Study 5	1,400–2,600 ms	fear (predictable)	after stimulus disappeared	train (0.5 s)	20 min