This is by design. For years, Twitter has been criticized for drowning its users in a sea of trivia. CEO Ev Williams has countered these critics by saying Twitter is all in how you use it. It is an empty vessel of meaning; if it stays empty, that's your fault.
There's a cottage industry of people, mostly publicists and marketers, trying to prove that Twitter is useful, and occasionally they sucker a journalist into writing about how people used Twitter to find service stations with gas during a shortage in Atlanta. (A couple of years ago, they'd have written the same story, but using Google Maps. A decade and a half ago, they'd have written the same story with this new thing called "email" as the technological hero.)
Back to the scientists. Their concern isn't so much with Twitter as with any rapid-fire media, including television and videogames. Human beings are wired to notice physical pain pretty much right away. More subtle problems, like emotional pain, take six to eight seconds to recognize. ScienceDaily summarizes the study and quotes one of its authors, Mary Helen Immordino-Yang:
The study raises questions about the emotional cost-particularly for the developing brain-of heavy reliance on a rapid stream of news snippets obtained through television, online feeds or social networks such as Twitter.
"If things are happening too fast, you may not ever fully experience emotions about other people's psychological states and that would have implications for your morality," Immordino- Yang said.
Immordino-Yang stresses that she doesn't blame social networks — just ones that shoot rapid-fire updates at us, like Twitter and the redesigned, Twitter-like Facebook. Does Twitter render us blind to our fellow human beings' pain? Do we use it to numb our own pain? I'd worry about it, but I have a thousand tweets to catch up on.