At last, science explains why there are Internet trolls [infographic]

Our brains are incapable of multitasking.

That's the claim of the folks at OnlineUniversities.com, which sent me nifty infographic "Digital Stress and Your Brain". There is a lot of interesting data, but two sentences caught my attention: "Our brains' attention levels are finite. When our brain is overloaded with information, it can trigger a 'fight or flight' reaction. The overload makes the brain feel threatened, so it shuts down higher brain functions that deal with empathy".

So there's explanation. So-called trolls -- you know, like obnoxious commenters -- have overloaded their lobes with too many tasks and in doing lost any feeling for anyone but themselves (being in fight, defensive mode). You'd probably find them to be the best of pals at the local pub. But behind screen and keyboard, they're beasts.

What I want to know, do the infographic's authors refer to the larger Internet population or just the Apple crowd? I ask because the graphics for cell phone, desktop computer, laptop, MP3 player and tablet are all Apple gear -- iPhone, iMac, MacBook, iPod and iPad.

Another relevant data point is worth calling out. One study of multitaskers found they "had a difficult time pulling information from short- or long-term memory into working memory". Surely you've never experienced anything like this? :)

I highly recommend The Shallows: What the Internet Is Doing to Our Brains by Nicholas Carr, for excellent treatise on how the web changes us -- and often not for the better. Distracted Web content overwhelms short-term memory. Nicholas writes: “When the load exceeds our mind’s ability to process and store it, we’re unable to retain the information or to draw connections with other memories.” Information fails to move from short-term to long-term memory, and it's lost.

I read The Shallows two years ago and highly recommend it.