We all feel like we’re addicted to e-mail sometimes. Now along comes someone to tell us why.

New York Times reporter Matt Richtel, interviewed on the NPR program On The Media, explained that in psychological terms, there is something called “intermittent reinforcement” – “that’s this idea that if you put a rat in a device where a food pellet only comes out of a hole periodically, the rat’s going to be checking that hold all the time because it never knows when that food is available.”

The same thing happens with e-mail, Richtel said. “Most of the stuff we get is plainly unimportant. But occasionally, something really important comes along. So what does that do? It randomly reinforces us to be checking all the time.”

In other words, we are not that much more evolved than the common rodent…at least when it comes to checking our iPhones ten times an hour. And it’s not just e-mail – Facebook status updates, SMS, chats – they’re all part of an addiction that, apparently, gets physical as well.

Richtel again: “when you check your device, you basically get the equivalent of a dopamine squirt. Well, if you get that little candy when you check your email and you check your phone, in its absence you start to feel bored.”

And when you feel bored, you want a new squirt. So what do you do? You send out a text or an e-mail or a Tweet, or you initiate a Facebook chat, all in the hope that you’ll get a response. It becomes an endless loop.

What does all this mean for Internet advertisers and publishers? Perhaps this: If you want to get your message out, steer clear of banner ads and choose more interruptive media. Build up your social media fans and followers. And keep them guessing as to when the next big announcement will arrive in their inboxes.

(The interview, by the way, was part of a larger discussion on “distracted driving” amid new laws forbidding texting while behind the wheel – see Matt’s articles here. The implications for advertisers when it comes to potentially fatal social media behavior are far more ominous.)

Brian Blum heads Blum Interactive Media, a consulting group that works with companies to jumpstart their businesses through comprehensive product planning and strategy.