Individual differences in sensory eye dominance reflected in the dynamics of binocular rivalry

Abstract

Normal binocular vision emerges from the combination of neural signals arising within separate monocular pathways. It is natural to wonder whether both eyes contribute equally to the unified cyclopean impression we ordinarily experience. Binocular rivalry, which occurs when the inputs to the two eyes are markedly different, affords a useful means for quantifying the balance of influence exerted by the eyes (called sensory eye dominance, SED) and for relating that degree of balance to other aspects of binocular visual function. However, the precise ways in which binocular rivalry dynamics change when the eyes are unbalanced remain uncharted. Relying on widespread individual variability in the relative predominance of the two eyes as demonstrated in previous studies, we found that an observer’s overall tendency to see one eye more than the other was driven both by differences in the relative duration and frequency of instances of that eye’s perceptual dominance. Specifically, larger imbalances between the eyes were associated with longer and more frequent periods of exclusive dominance for the stronger eye. Increases in occurrences of dominant eye percepts were mediated in part by a tendency to experience “return transitions” to the predominant eye – that is, observers often experienced sequential exclusive percepts of the dominant eye’s image with an intervening mixed percept. Together, these results indicate that the often-observed imbalances between the eyes during binocular rivalry reflect true differences in sensory processing, a finding that has implications for our understanding of the mechanisms underlying binocular vision in general.

A comparison of tests for quantifying sensory eye dominance

“…This is consistent with earlier reports of 420 participants' first percept of a rivalrous display predicting their eye dominance (e.g. quantified using percept frequency) calculated for stimuli that alternated over dozens of seconds (Xu, He et al 2011, Dieter, Sy et al 2016). …”

“…Specifically, pairs of contrast-modulated stimuli were used in tests #1-6, comprising Sloan letters (adapted from Kwon, 395 Wiecek et al 2015-tests #1-2, Bossi, Tailor et al 2017, reciprocally-shifted gratings (from Ding and Sperling 2006 -tests #4-5) or up/down drifting noise-patterns(loosely based on the motion task by Black, Thompson et al 2011 -test #6). Test #7 (inspired by Dieter, Sy et al 2016) measured rivalry, as the proportion of dominant-eye instances (presenting the same pairs of stimuli used in # 6 but at a fixed contrast). In addition, test #8 measured stereoacuity, using stereo-defined Sloan letters (variant of 400 Frisby, Davis et al 1996).…”

Frequency of alpha oscillation predicts individual differences in perceptual stability during binocular rivalry

“…Finally, there can be a large individual variation in how much each of the two eyes contributes to dominance. Some individuals possess a highly dominant eye for which perceptual durations are much longer duration than those for the weaker eye (Dieter, Sy, & Blake, ). Such unequal dominance likely arises due to various factors at early stages of visual processing, and may make it difficult to characterize cortical contributions to dominance duration.…”

“…Finally, there can be a large individual variation in how much each of the two eyes contributes to dominance. Some individuals possess a highly dominant eye for which perceptual durations are much longer duration than those for the weaker eye (Dieter, Sy, & Blake, 2017).…”

Visual plasticity and exercise revisited: no evidence for a “cycling lane”

“…To give a measure that is independent of the shape of the histogram, we used the total time that the subject responded that they were seeing the stimulus for the patched or non-patched eye. We used this to calculate the ocular dominance index after Dieter, Sy & Blake (Dieter et al (2017); Equation 1)…”