I’ll freely admit it; I’m addicted to Puzzle & Dragons, and I’m certainly not the only one. I have clocked up my 211th consecutive day playing what reviewers have described as “portable crack“, and I’m surprised at that. There have been plenty of casual gaming titles that have kept me interested briefly, but nothing has come close to 211 consecutive days of logging on, without fail. When I needed to replace my phone, my PAD game state was the only thing I worried about backing up. How has it managed to keep me interested? By consistently and successfully applying principles of “intermittent positive reinforcement”.