This is entirely anecdotal, and as I have ADHD this may not be the norm; but I have noticed throughout my life so far that my attention span is a product of what I pay attention to. If I am primarily consuming content to enrich myself or critically analyze something, my attention span tends to be longer for a period of time. Conversely, if I am consuming content to socialize or out of boredom, my attention span short…
I wonder if stress is the causal mechanism for focus here? Maybe not entirely but a proportion of it.
I think speculation is allowed here since the author was unable to draw substantial conclusions either. But did distill a lot of useful information together.