Every year a fresh gadget arrives on the market with a headline that reads something like “the future is now”. Touch screens, voice assistants, biometric scanners – all of them are sold as answers to the problem of friction. The idea is appealing: a single surface that can do everything, a single voice that can command everything, a single card that can pay everywhere. In theory the world becomes smoother, faster, more elegant.

But the reality is that most of these inventions are created without a seat at the table for people who experience the world differently. When a design team assumes that every user can see a bright icon, tap a tiny button and speak a clear command, they are building a wall as much as a bridge. The wall is invisible to those who do not need to climb over it, but it is solid and unyielding for the rest of us.