An article titled "Widely cited study of fake news retracted by researchers [nypost.com]" indicates that a strong link between attention span and the spread of fake news was oversta..squirrel!..err...overstated.
The original article [nature.com] initially indicated
both information overload and limited attention contribute to a degradation of the market’s discriminative power.
it turns out there was an error in the researchers’ analysis that invalidates their initial conclusion
The researchers promptly notified the journal upon discovering the problem, however the journal deliberated whether to correct or retract the article for a year before taking action.
No explanation was provided for Nature [nature.com] leaving the article uncorrected so long.
The authors indicate that the analysis would more correctly now indicate that
The results of our paper show that in fact the low attention span does play a role in the spread of low-quality information, but to say that something plays a role is not the same as saying that it’s enough to fully explain why something happens. It’s one of many factors.
Still, the whole concept of spending 15 seconds on an item before forwarding or 15 minutes reading, checking links and reading those, maybe swinging by Snopes... seems quite an obvious factor in whether an individual weeds out 'fake news' in their travels or not. I guess it isn't until the 21st century that we discovered Reading is Fundamental [rif.org].