I don’t think there is such a thing as an “intuitive” user interface (UI), however, I do believe there is such a thing as a guided UI, one which walks you through the process.
I was talking with Nik and Dan on the subject of the self checkout tills at Sainsbury’s and Nik was explaining a recent example he saw of where the hand-holding falls down. He saw a guy scanning an item, paying for it and then scanning a new item and paying for it etc. Now granted this method works, however the intention is that you scan all your items and then pay. Where on the user interface does it tell you this? Last I looked there were no visual clues, just the assumption people would expect it to work as the other tills do.
Today I found another hole I think. I scanned in items then I shoved my card in the reader expecting to be asked my pin etc. Instead I was met with an error telling me my card was being rejected by the authorizing body. So I tried another card, same error. I eventually realised that I had made a mistake, I had not hit the “Finish and Pay” button. Now fair enough this error was down to my mistake, however, how did that error message help me? It led me away from the real problem!
What really irks me about this is why don’t they allow you to shove the card in to signal you are ready to pay? I mean, if I hit Finish and Pay and then instead of selecting “cash” or “card” just put the card in it is quite happy with that.
So Sainsbury’s, relevant error messages and more short-cuts please.