We used a non-transient probe (500 ms lifetime, with a standard deviation of 100 ms) to make our study comparable with Watanabe
et al (2005 Vision Research). In preliminary experiments, we also utilized a transient, 100 ms probe, and the results were
qualitatively similar to the 500 ms, non-transient probe. We attach additional data from the first author with the same format
as in Figures 1, 2, 3 in our manuscript.
Supplementary Figure 1. NT's threshold with a transient probe (left) and one with a five-times longer lifetime (right, data
taken from Figure 1 in the PDF). Note that although the threshold is much lower for a transient probe, the overall pattern
of the result is essentially the same.
Suppplementary Figure 2. SOA dependency with a transient probe (left) and a non-transient probe (right). Note that the tuning
is sharper with the transient probe, but the main experimental findings remain the same.
Suppplementary Figure 3. The same format as Figure 3b for a transient probe (left) and a non-transient probe (right). The
notable difference is that with the brief (100 ms) transient probe, 2-flash suppression is as effective as CFS.
In another preliminary experiment, we tested a wide range of spatial frequencies (0.45–3.6 cpd) for the probe and the background
grating. There were 3 conditions: monocular, BR, and CFS; the probe duration was always 100 ms. Two subjects were tested.
Suppplementary Figure 4. Threshold contrast increment as a function of the spatial frequency of the probe grating for monocular
(red), BR (blue), and CFS (green) conditions. Data are taken from the first and the second authors. Error bars are SEM.
Supplementary Movie 1. Color anaglyph demonstration of CFS in the probe task. In this demonstration, a 10 Hz stream of Mondrian
is presented through the red filter and the background grating through the green/blue filter. The upper or lower half of the
grating smoothly increases its contrast over 500 ms, serving as a contrast increment probe for the detection task. Note that
in the actual experiment, the stimuli are presented dichoptically using a mirror setup and they are in gray scale except for
a red fixation cross.