Subway maps may have been as hard for some people read as more complex visualizations are now — the notion of mapping topology onto a 2D plane that abstracts the experience from traditional space is not a native one with humans.
But it’s not just education; some researchers have argued that our whole world is now engineered to make us think in this way, thanks to an increasing reliance on technology. Where our great-grandparents may have grappled with typewriters, our parents struggled to program their video recorder, while children today learn to use a touchscreen from an early age. Even reading the schematic London Underground map may have been tough for someone in the 1900s who was used to seeing the world more literally, Flynn says. This progression has forced us to think in hierarchies and symbols, to learn how to follow rules and draw analogies – and it is now so widespread that we forget the cognitive leaps it requires. (Source)