How to set up a binocular rivalry experiment which splits a single image in two separately controlled ones? The question is about the actual physical setup and steps needed to take in order to experiment with the phenomena. I found a tutorial on jove.com, "How to Create and Use Binocular Rivalry", and it also has a dedicated explanatory article. However, the experiment I want to make is tricky in the following sense:

A regular binocular rivalry experiment has two separate images set up, and normally the image features are controlled in a way that is suitable to exhibit a whatever the experimenters want. In the case that I want to make, images are not separate, they are basically left and right parts of a single image that is usually viewed as a single image as well. 

In the experiment, I will manipulate left and right halves of that single image separately, but I want to present halves to different eyes. The particular problem is that I want to calibrate the physical setup so that the physical boundary between images is not exactly visible. I can't just split left and right - the border between the images in the eyes of the observer has to be as small as possible.

How can I present each half of a face, split vertically down the middle, independently to each eye (e.g., left half-left eye), without putting a visible physical boundary between the two image halves?
This is an interesting methodological problem. On the one hand, it seems that any method which would present the halves to the correct eye, and only that eye, would entail a visible boundary, and any method with an invisible boundary would be unable to present the halves as desired. Virtual reality systems present stimuli to each eye separately (e.g., the commercial Oculus Rift), and may therefore present a solution here. It is, however, conceivable that the brain will not correctly integrate two separately presented halves of a face into a percept, and I am not aware of any direct studies, nor can I find any. 

One related and interesting example of using virtual reality to study complex visuo-motor behavior, the outfielder problem, was provided by Fink, Foo and Warren (2009). They equipped participants catching baseballs in the air with a Cybermind Visette-Pro HMD virtual reality helmet in order to manipulate the perceived motion of the baseballs. Their ability to successfully execute such a complex visual manipulation suggests that virtual reality systems should be a viable solution for presenting halves of faces independently to each eye.

References


Fink, P. W., Foo, P. S., &amp; Warren, W. H. (2009). Catching fly balls in virtual reality: A critical test of the outfielder problem. Journal of Vision, 9(13), 14.