In 2005 (a full three years before the launch of the App Store), a brain training video game became an overnight sensation in a way that would not be seen again until 2016’s Pokemon Go. The game was everywhere. The premise was simple. You solve the puzzles in as short a time as possible and the game – which was ostensibly based on principles of neuroscience – would tell you your mental age. It was sort of a fun way for people who knew they were smart to show off, and for those who knew their cognitive abilities had been collecting dust since high school to share a laugh at their pre-teen mental age.