Figure 1.

Memory-threat task. (a) The figure provides an illustration of the Memory-threat task during the threat condition of a partial 2-back block. Participants responded to every letter indicating whether the currently presented letter was the same as (S; the target) or different from (D; the distractor) the letter presented two letters back (e.g., same = z and Z; different = J and G). The letters presented at the beginning of the block, for which a response could not be made (i.e., going n letters back would fall onto the instruction screen, were considered to be distractors. The startle probe and threat stimulus were presented during the ITI. (b) The figure provides an illustration of one run (8 blocks) of the Memory-threat task. Blocks interchanged between the threat and safe conditions. Three startle probes were presented in every block, and 0 to 2 loud screams were presented during the threat blocks.