Is it dangerously addictive? And what is addiction, really?
Brain is a muscle just like any other muscle and obviously we need to use it to grow 'strong'. Addiction in the meaning training your brain for hours shouldn't cause any worries with respect to children playing on the computer. On the contrary, it is good news.
Addiction is just another word for being able to concentrate or focus for a long time. :-)
I would turn around the 'color' of this article and say that according to the latest science we see proof that training your brain actually works. :-)
Then again, contradicting myself, the fact that we can conclude opposing claims from the same experiment underline one of my frequently used arguments concerning neuroscience -and that is that just because we see physical changes in the brain, it doesn't enable us, by scientific methods, to conclude what that means in terms of behavior or emotional results.