Figure 1

Experimental procedure. The left column depicts the different sessions and their order (calibration, invisible condition, visibility tests, visible condition and unmasked condition). At the center, the experimental sequence in the main runs, and on the right are the two post-test visibility runs. In all trials, one experimental sequence was repeated three times, separated by 0–4 masks to avoid temporal predictability of the target image. The experimental trials ended with only one question about target visibility. In the post-test trials, this subjective visibility question was preceded by an objective question (about target congruency/orientation). Each experimental sequence included one presentation of the target scene, which was either congruent or incongruent, and forward and backwards two masks which either immediately followed and preceded the scene (invisible condition) or were separated from it by blank frames (visible condition). Thus, throughout each trial, the target scene was presented three times.