I'm not asking for evidence about the author. I'm asking, is there any scientific research into the matter in general? If there was any research on the matter,

I'm not asking for evidence about the author. I'm asking, is there any scientific research into the matter in general? If there was any research on the matter, it wouldn't be "purely a personal preference". If the author had data about their personal productivity, they would probably have mentioned it in their blog post, no?