Paragraph boundaries

Boundaries may result from natural properties of the mind or sometimes from conscious decisions. “Nothing is more distracting for a native speaker than to have the eyes misguided by written lines that don't begin where they should or end where they should” (Seal 1979 p.4). How successful can language learners fulfill such a challenging task? Are they able to identify paragraph boundaries accurately? Can they paragraph effectively when they engage in writing task? Is there a positive correlation between accurate identification and production of paragraph boundaries?