First of all, this article includes only anecdotal evidence. Secondly, it fails to provide an adequate definition of the problem. You can easily find a single

First of all, this article includes only anecdotal evidence. Secondly, it fails to provide an adequate definition of the problem. You can easily find a single big, high-res panel that has more screen real-estate than a pair of 1080p panels, but would one of these be better for your focus because it's a single display? This claim is not logical. If you can augment your working memory with more screen real estate you should benefit. If you use screen real-estate to display extraneous, distracting data such as weather, email, news, etc. you might suffer. Whether or not your screen real-estate has a line down the middle dividing it into two chunks shouldn't make a difference.