Impact of Correlated and Uncorrelated Noise on Binocular Perception

Numerous studies have established advantages of binocular over monocular vision, including increased contrast sensitivity arising as a result of binocular summation. However, there remains inadequate understanding regarding several aspects of binocular summation. The present study sought greater understanding of factors potentially broadening, or limiting, the extent to which binocular summation explanations can be applied. In particular, binocular summation effects have not been adequately investigated within the context of external visual displays presenting dynamic noise. The present study investigated whether dichoptic viewing of a signal in uncorrelated visual noise conditions confers a perceptual advantage over that in correlated noise in visual detection and discrimination tasks. A repeated-measures design was utilized, manipulating noise type and level of noise correlation presented through a head-worn display device. The dynamic externally presented noise included characteristics resembling night vision goggle (NVG) noise, while levels of correlation emulated the physical image configuration of NVG device types (binocular and biocular). An adaptive 1-up/2-down staircase procedure was used to obtain contrast sensitivity threshold estimates. Results did not adhere to established binocular summation model predictions, and differences were inconclusive of any perceptual advantage in uncorrelated noise conditions. Discussion addresses potential limiting factors to the study results