Did we need a study to reach this conclusion? A short period of observation would suffice just as well. Nonetheless, a team of Italian economists conducted a study on Twitter’s impact on cognitive abilities, and discovered that it makes hash(tags) out of them.

Be careful about the siren song of confirmation bias, however:

The finding by a team of Italian researchers is not necessarily that the crush of hashtags, likes and retweets destroys brain cells; that’s a question for neuroscientists, they said. Rather, the economists, in a working paper published this month by the economics and finance department at the Catholic University of the Sacred Heart in Milan, found that Twitter not only fails to enhance intellectual attainment but substantially undermines it. “It’s quite detrimental,” Gian Paolo Barbetta, a professor of economic policy at the private research university and the paper’s lead author, said in an interview with The Washington Post. “I can’t say whether something is changing in the mind, but I can say that something is definitely changing in the behavior and the performance.”

Normally, study results of this type should produce some pro forma skepticism. One study on its own doesn’t mean much, except to point out the need for further studies to see if the results are reproducible. Many of the studies seized on by media outlets tend to be poorly constructed, with small sample sizes and directed results.

This study does seem appropriately designed though, using 1500 high-schoolers in a double-blind test. The task was to analyze a classic literary novel, with half of the students doing so on Twitter engaged with classmates and teachers, and the other half using only a normal classroom experience. It’s not tough to guess which group did better, but how much better is rather surprising:

Using Twitter reduced performance on the test by about 25 to 40 percent of a standard deviation from the average result, as the paper explains. Jeff Hancock, the founding director of the Stanford Social Media Lab, described these as “pretty big effects.” Notably, the decline was sharpest among higher-achieving students, including women, those born in Italy and those who had scored higher on a baseline test. This finding, the paper notes, bolsters the conclusion that blogs and social networking sites actively impair performance, rather than simply failing to augment learning.

That’s another reason to retain a little skepticism about this study. Their conclusion reaches past its parameters; at least according to the Washington Post, the study specifically was limited to Twitter. That’s a different experience than some other social-media platforms, and far different than blogs. (Hey now…) Well-run studies keep their conclusions within the boundaries of their tests.

In fact, the cognitive problems with Twitter may very well be its differences, as those who have grown frustrated with the platform well know. Its character limit rewards pithiness over thoughtfulness, and promotes zingers over analysis. Even in the best of environments, Twitter is less a place for reasoned discourse than for gossip and pleasantries. Thanks to Twitter management’s heavy-handed “community standards” policies and the snitch-society incentives they have created, the best of environments has long since departed.

Either way, Twitter is not built for education, especially for the kind of nuance and depth that literary analysis requires. No one is seriously proposing that Twitter would serve that purpose either, which is yet another reason to be skeptical about this study and its motives. Among social networks, Facebook might be better suited for that task, but nothing will replace the classroom environment for education. A better question would be whether on-line education produces significantly different cognitive outcomes — but the answer might not please the educational establishment that would run that study.

It’s still an interesting outcome, even if it’s entirely theoretical. Perhaps more studies will follow that deals less with comparisons to classroom situations and more with Twitter’s impact on cognitive abilities in general, and more broadly on social-network platforms in general. Until those come and produce similar results, however, don’t take this one too seriously.