Figure 1

Schematics of the experiments. (a) Experimental procedure of the duration discrimination task. Three brief flashes or tones were sequentially presented, and subjects judged whether the first was longer or shorter than the second. The order of standard and comparison stimuli was counter-balanced. (b) Experimental procedure of the duration reproduction task. Two brief flashes or tones were sequentially presented, and subjects pressed buttons to reproduce the duration. A sensory feedback was presented immediately after the subjects’ responses. (c) An example of noise manipulation for visual stimuli. The background noise intensity was 0.66 (High), 0.22 (Low) or 0 (No) times the threshold noise level measured in the detection threshold task (see Methods section).