Earlier this week I went to an ATM to deposit a check. The procedure on the new Green Machines is pretty straight-forward. Select ‘deposit’, enter the amounts, choose account to deposit to, put your deposit items (checks or cash) in envelopes and feed those envelopes to the machine.
In this procedure I found two minor problems, both problems with affordance. Affordance is “a goal-relevant description of the world that describes an opportunity for action defined with respect to the capabilities of a particular actor” – definition found in ‘Cognitive work analysis’ by Kim J. Vicente, originally from J.J. Gibson. The key term here is opportunity for action. Affordance describes what an actor can do with an object (and related: what one thinks one can do, and what one cannot do). A classic example is pushing or pulling a door: if there is no handle but only a plate the door doesn’t afford the action ‘pulling’.
Back to my ATM. The first problem came up when I was asked to which account I wanted to deposit. I was given three options: checkings, savings and visa. Upon selecting ‘savings’ I got an error message: “invalid account”. I tried ‘visa’ and got the same message. Fortunately, the checkings account was not considered invalid.
My second problem was a little different. I put my check in the envelope, sealed it, and found the right slot on the machine. So far, so good. But when I watched my envelope disappearing into the machine I noticed there where 3 little arrows printed on it, not facing the machine’s way but mine. It clearly suggested I had done something wrong! The good thing is that it didn’t come back and I got my money. The bad thing is that the machine gave me wrong expectations, I really expected having to give it another try.
Lessons taught by this green machine:
- Please give your users only valid options to choose from! Invalid options will only cause frustration. (Unless you are absolutely confident they will never choose them, reminding me of the waiter scene in the movie ‘La vita รจ bella’).
- When multiple actions are allowed, reflect this in your design. Do not suggest they are not allowed.
For software products pay attention to suggestions of clickability, drag-and-drop behavior, and temporarily disabling buttons when their associated actions don’t make sense. Little things to make a user-friendlier product.