Figure 1.

Computer-based escape-avoidance task. (A) An enemy spaceship appears in one of six locations on the screen, approximately every 1 s. The participant’s goal is to gain points by shooting and destroying this spaceship (1 point for each hit). (B) The warning signal is two colored rectangles at the top of the screen, which appear every 20 s and remain visible for 5 s (warning period). (C) The warning signal is always followed by appearance of a bomb, which remains onscreen for 5 s (bomb period). The bomb period is divided into five segments of equal duration; during each segment there is an explosion and loss of 5 points to a maximum of 25 points. (D) At the bottom corners of the screen, there are two box-shaped areas representing “safe areas.” Moving the subject’s spaceship to one of those boxes is defined as “hiding.” While hiding, the subject’s spaceship cannot be destroyed and no points can be lost, but neither can the subject shoot the enemy spaceship and gain points. Subjects were not given any explicit instructions about the safe areas or the hiding response. Labels shown in white text are for illustration only and do not appear on the screen during the task.