(A) Trace conditioning: The experimental condition, hypothetical temporal representations, and observed result of Cole, Barnet, and Miller (1995, Experiment 1). (B) Simultaneous conditioning: The experimental condition, hypothetical temporal representations, and observed result of Barnet, Arnold, and Miller (1991). (C) Backward conditioning: The experimental condition, hypothetical temporal representations, and observed result of Molet, Miguez, Cham, and Miller (2012, Experiment 2). Open rectangles and letters represent conditioned stimuli; black rectangles represent the footshock unconditioned stimulus. CR = strong conditioned responding (i.e., suppression).