There are plenty of scientific studies on the pros and cons of social media. Somehow our digital life simultaneously makes us sadder, smarter, more inclined to run up our credit card bills, and in the specific case of looking at our own Facebook profile, overconfident, and thus a little dumber.

Now, Stanford University professor Clifford Nass, who studies the social and psychological impacts of media, has another point for the "cons" column. His research shows that chronic multitasking — switching back and forth between types of interactive media — makes us worse students, worse workers, worse managers, and all-around less sensitive people.

In a recent TED Talk (which you can watch below), Nass explains how college students "triple and quadruple-book media." He says, "When they're writing a paper, they're also listening to music, using Facebook, watching YouTube, texting etc."

To see what impact this has on their brains, in one study, Nass tasked 262 college students with completing three experiments that examined different aspects of multitasking: Switching quickly from one task to another, filtering out irrelevant information, and using what is called "working memory," an aspect of short-term memory that allows you to hold multiple pieces of information in your mind.

The results? Chronic multitaskers have a harder time with everything: Telling what information is relevant, managing working memory, and ignoring irrelevant information. And the weirdest part: They're also pretty bad at multitasking. "The research is almost unanimous, which is very rare in social science, and it says that people who chronically multitask show an enormous range of deficits," Nass told NPR. "They're basically terrible at all sorts of cognitive tasks."

He says, "It's a little like smoking. You know, saying, I smoke all the time, so smoking can't be bad for me. Unfortunately, it doesn't work that way."

You can see how this would make people less productive. But chronic multitasking has another impact, too: It lowers people's "emotional intelligence." James O'Toole in Strategy Business explains:

Multitaskers are not only paying no attention to their profs (or to their bosses, co-workers, and customers in the room with them), they have problems with social interactions in general. In terms of developing what Daniel Goleman calls "emotional intelligence," new media addicts are poor at reading other people. In short, they tend to be socially and emotionally immature. They prefer to retreat to the comfort of texting rather than deal with potential emotional connection (and conflict) with those in the same room. [Strategy in Business]

Nass argues this also applies to managers, according to The Harvard Business Review:

Media multitasking makes managers less thoughtful and more inclined to exercise poor judgment, Nass says. And companies that encourage people to respond instantly to e-mail make the problem worse. At the very least, managers should insist that employees bring no electronic devices to meetings. [HBR]

For more on the perils of multitasking, watch Nass' TED talk: