Assessing the generalizability of eye dominance across binocular rivalry, onset rivalry, and continuous flash suppression

It is commonly assumed that one eye is dominant over the other eye. Eye dominance is most frequently determined by using the hole-in-the-card test. However, it is currently unclear whether eye dominance as determined by the hole-in-the-card test (so-called sighting eye dominance) generalizes to tasks involving interocular conflict (engaging sensory eye dominance). We therefore investigated whether sighting eye dominance is linked to sensory eye dominance in several frequently used paradigms that involve interocular conflict. Eye dominance was measured by the hole-in- the-card test, binocular rivalry, and breaking continuous flash suppression (b-CFS). Relationships between differences in eye dominance were assessed using Bayesian statistics. Strikingly, none of the three interocular conflict tasks yielded a difference in perceptual report between eyes when comparing the dominant eye with the nondominant eye as determined by the hole-in-the-card test. From this, we conclude that sighting eye dominance is different from sensory eye dominance. Interestingly, eye dominance of onset rivalry correlated with that of ongoing rivalry but not with that of b-CFS. Hence, we conclude that b-CFS reflects a different form of eye dominance than onset and ongoing rivalry. In sum, eye dominance seems to be a multifaceted phenomenon, which is differently expressed across interocular conflict paradigms. Finally, we highly discourage using tests measuring sighting eye dominance to determine the dominant eye in a subsequent experiment involving interocular conflict. Rather, we recommend that whenever experimental manipulations require a priori knowledge of eye dominance, eye dominance should be determined using pretrials of the same task that will be used in the main experiment.