Each time we check a Twitter feed or Facebook update, we encounter something novel and feel more connected socially… and get another dollop of reward hormones. But remember, it is the dumb, novelty-seeking portion of the brain driving the limbic system that induces this feeling of pleasure, not the planning, scheduling, higher-level thought centers in the prefrontal cortex. Make no mistake: email-, Facebook- and Twitter-checking constitute a neural addiction.

via Replacing Twitter with Phone Calls: An Adventure in Unplugging – 99U.