Could take a look into the brains dopamine response to playing games like fruit machines and how it compares to other forms of gambling. I mean social media has fine tuned their platforms to get us hooked on notifications, likes etc. So I could imagine some fruit machines having a similar effect on the brain as smartphones. Also I wager that fruit machines scratch the itch of our brain to perceive patterns in everything. I would be interested to read any research you produce. Please post!!