No More Than Two

London’s “convenience” stores are replacing staffed checkouts with self-service robots. Some of these offer lessons in user interface design painful to behold.

This evening I watched someone attempt to use one to buy paracetamol. The particular self-service robot checkout that I saw presented the user with a message very much like “paracetamol sale: you may only buy two packs” above a yes/no button pair. What is the casual paracetamol buyer to make of this? I watched with interest as my co-emptor pondered this. And then she did the only reasonable thing: she went and got a second pack. After all, it does say you may only buy two packs.

Quite what anyone is supposed to make of the yes/no buttons following a statement not a question I don't know.

The really sad thing is that, apart from the shame of confusing your customer, the behaviour I saw here—which I believe is the only reasonably response to the message from the robot—is the exact opposite of what is intended.