I've never heard of this typography concept: asym spacing.
But one tech company believes something as simple as increasing the size of spacing between certain words could improve people’s reading comprehension. Research going back decades has found that “chunking,” a technique that separates text into meaningful units, provides visual cues that help readers better process information.
The image below shows the before and after of Asym’s spacing on a paragraph of text. Quartz is also experimenting by manually adding Asym’s spaces to this article. The effect is subtle, but likely will irk keen-eyed copy editors (sorry!), especially those from the print world who are accustomed to deleting extraneous spaces.
No idea if the science behind this is solid, but I have heard of chunking. When I took a speed-reading class in grade school, they taught us two key principles. One was not to read aloud “inside your head,” and the other was not to read linearly, one word at a time, but to look at chunks of words (which also makes it hard to read linearly).
Maybe because I already chunk groups of words in regularly spaced text, or maybe because the asym spacing bunched odd groups of words together, I found the regularly spaced text (on the left) easier to read.