Most of us are familiar with ATM machines. If you deposit or withdraw money from a bank, rent from a Redbox DVD machine, or have bought from a soda machine, you’ve likely used an ATM like machine.
This specific experience I had highlighted the subtle but important fact around design and how to design in such a way that it helps the human. In other words, how to help the human prevent mistakes that he or she would likely make – because they are human.
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Conversely, there are designs that actually encourage mistakes. I believe this is one of those types of designs.
At an ATM recently, I found myself repeatedly hitting the “HELP” button. No, I didn’t mean to hit the “HELP” button – it was all accidental. Can you guess why from the image below?
That’s right, the “ENTER” button is right next to the “HELP” button.
As with most things, we bring our past experience into the situation and I’m accustomed to having the “ENTER” button on the far bottom right of the interface. So, my muscle memory immediately went to that location. But, on this interface, the button that occupies that location is the “HELP” button.
I made this mistake once, then twice. Then, I realized what was happening. But, my muscle memory immediately went to that location on the interface. Unfortunately, the interface encouraged me to make that mistake.
Redesign the ATM
Poka-Yoke, as we understand it, is a method to error proof or mistake proof our processes and devices. In fact, instead of catching the defect after it happens, Poka-Yoke is an approach that prevents the defect all-together.
One way to improve this interface is to move the “HELP” button away from the “ENTER” button. Having it close to the “ENTER” button can easily lead one to “fat finger” the “HELP” button unintentionally.
It’s Your Turn
What about you? What experiences do you have with everyday products and devices that could use some application of Poka-Yoke?
I agree, make the enter button obvious (corner) and larger (and green – which at least they do a little bit). One good bit of mistake proofing lots of ATMs do is giving you some common choices – just one button to get various amounts of cash. Instead of having people try to enter 100 (and mistakenly entering 10 or 1000…).