Prior to the analysis, the trials on which the response was incorrect (3.2%) and the detection time was shorter than 100 msec (0.1%) were discarded. The mean detection time was calculated in different eye-of-presentation conditions for each observer and then averaged across different observers (
Figure 2). The detection time was analyzed by using a two-way repeated-measures analysis of variance (ANOVA) with the suppressor (absent/present) and the eye of presentation as factors. We observed significant main effects for the presence/absence of suppressor,
F(1, 11) = 106.11,
p < 0.001,
\({\rm{\eta }}_p^2\) = 0.91, and the eye-of-presentation,
F(3, 33) = 51.37,
p < 0.001,
\({\rm{\eta }}_p^2\) = 0.82. An interaction was also significant,
F(3, 33) = 49.53,
p < 0.001,
\({\rm{\eta }}_p^2\) = 0.82. This significant interaction reflected differential effects of the eye of presentation; the detection time was significantly modulated when the suppressor was presented (gray bars in
Figure 2),
F(3, 33) = 50.83,
p < 0.001,
\({\rm{\eta }}_p^2\) = 0.82, whereas it was not when the suppressor was absent (white bars in
Figure 2),
F(3, 33) = 1.45,
p = 0.245,
\({\rm{\eta }}_p^2\) = 0.12. Furthermore, post hoc analysis with Bonferroni correction (α = 0.05/6) revealed that when the suppressor was present, the detection time in the 3.5-Hz eye-swapping condition was shorter than that in the dichoptic and the 1.2-Hz eye-swapping conditions,
t(11) = 3.39,
p = 0.006, and
t(11) = 4.13,
p = 0.002, respectively, whereas it was longer than that in the monocular condition,
t(11) = 5.76,
p < 0.001. The analysis of the simple main effect of the suppressor revealed that the detection time was significantly increased with the suppressor in all eye-of-presentation conditions,
F(1, 11) = 22.43,
p < 0.001;
F(1, 11) = 180.51,
p < 0.001;
F(1, 11) = 92.83,
p < 0.001; and
F(1, 11) = 38.14,
p < 0.001, for the monocular, dichoptic, 1.2-Hz, and 3.5-Hz eye-swapping conditions, respectively.