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. Author manuscript; available in PMC: 2015 May 15.
Published in final edited form as: Nature. 2015 Jan 21;520(7547):345–348. doi: 10.1038/nature14106

Figure 1. Incidental encoding paradigm and example stimuli.

Figure 1

Adult human subjects viewed 90 basic-level exemplars of animals and tools before, during and after fear conditioning. Before and after fear conditioning, subjects classified each object as an animal or a tool. During conditioning, electric shocks were paired with 20 out of 30 animal or tool pictures (counterbalanced between subjects) while subjects rated shock expectancy. A surprise recognition memory test was administered 24 h (n = 30), 6 h (n = 30), or immediately (n = 29) after encoding. Lightning bolts denote electric shocks.