Learning Through Natural Feedback on the London Underground

One of the best ways of teaching users how a software or physical product works is through feedback. Some types of feedback are explicit, such as a well-placed error message presented when we fill out an online form field incorrectly, or a supportive tick when we fill out the field correctly. Other types of feedback are implicit and require us to learn a connection between the feedback and the correct way to use an object or system. Regardless of type, the best feedback occurs naturally and at just the right time.

A nice example is the implicit feedback provided by the entry and exit barriers in the stations of the London underground. To pass through a barrier, passengers insert their ticket at the front of the barrier’s ticket-validation machine and retrieve it from the top. Because a passenger’s primary goal is to pass through the barrier, once the barriers have opened, their goal is complete. Retrieving the ticket for later use is not a primary goal and therefore passengers are likely to forget their ticket.

To prevent passengers forgetting their ticket, the barrier doors don’t open until the ticket is taken from the ticket-validation machine. On first use, some passengers may wonder why the barrier didn’t open even after the ticket passed successfully though the ticket-validation machine and appeared at the top. However, because the natural next step is to take the ticket to inspect it for damage and reinsert it into the machine and try again, the act of taking the ticket opens the barrier and starts the learning process. The next time the passenger passes though a barrier, the same behavior reinforces the passenger’s mental model of how the ticket barrier works. This is feedback at its best.

We’re all familiar with this type of feedback, of course. It’s exactly the same type of feedback we get when using an ATM. Before dispensing cash, ATMs require that customers remove their card from the machine. Banks learnt long ago that customers forget their ATM cards after taking their cash from the machine. Why? For exactly the same reason passengers forget their underground tickets: once we’ve accomplished our primary goal, we tend to forget about the supporting tasks or objects required to accomplish our primary goal. As soon as customers have taken their cash from an ATM, their primary goal of withdrawing cash is complete. Retrieving an ATM card is not a primary task and can easily be forgotten.

Humans have a natural ability to learn quickly from well-designed feedback. If you exploit that ability in your designs, your users will appreciate it.

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