Saturday, February 2, 2008

Interactive Design: A Case Study Part 2 of 3

New York's MetroCard Vending Machine (MVM) detail
MetroCard Vending Machine Close-up

This post is part of a series exploring interactive design in an everyday object, the MetroCard Vending Machine. Please click below to read further:

Part 1
Part 3

The MVM interface uses large, high-contrast graphics and a clearly articulated sequence to make a cohesive experience for a diverse metropolitan public. The MVM conforms to many usability heuristics. Its interface presents a minimalist design that eliminates irrelevant information on the screen. For example, the main action appears on the middle of the screen while buttons on the bottom of the screen allow users to go back or proceed with the transaction, as well as a way to cancel. It is also flexible for beginner and advanced users, offering shortcuts for frequent actions. Throughout the transaction, there are consistent messages to the user.

It was important to make the interaction of the MVM work successfully with both the hardware and the interface design. The input and output interaction styles communicate useful and consistent messages to the user. For example, special promotions or messages can be can be uploaded to all the machines in the system. In addition, fault conditions, such as exhaustion of supplies or change will be reported on the animated display, as well as communicated to the departments responsible for their upkeep.

The user interface is a touch-sensitive display. Customers interact with the machine by pressing “buttons” displayed on the screen. Masamichi Udagawa and Sigi Moeslinger, the founders of Antenna Design, state, “The user doesn’t distinguish between hardware and software… People may not consciously realize that something’s successful, but what makes it successful is that you don’t notice it.” With this in mind, the concept behind input and output interaction styles is to have them disappear into the experience, so that the user is not aware he or she is using a machine. The action seems effortless.

The original design of the MVM in the early 1990s was unsatisfactory. When it was evaluated by eight focus groups of diverse participants, no one wanted to interact with it. “All the groups said the box was intimidating,” said Udagawa. “The layout of the front was incomprehensible, scary looking, and nobody wanted to touch it. Even after telling people to hit a certain button, they wouldn't proceed.” The original prototype looked like a refrigerator, and focus groups were confused with the MVM’s input and output modules. To improve this situation, colored ceramics were added to the machine to highlight each area’s function, which interact with the colors on the screen. (For instance, a green screen symbolizes cash, which means go to the green area of the machine to insert money). The effect was to make the MVMs “Coney Islandish,” portraying a sense of fun and brightness in the dark subway.

Additionally, when Udagawa was redesigning the project, he had to think about people’s mental models. He compared the experiences of a traditional vending machine to that of a store. Users preferred a store experience because they were able to find what they wanted first then pay for it. It made them uncomfortable to insert their money first.

When the machines were first introduced in 1999, users were first intimidated by the machines, saying that they looked too "complicated" and "hectic." As reported in the New York Times, an elderly woman who was unfamiliar with computers used the machine successfully and was sure she needed help from a transit worker only one more time before she would feel completely comfortable with it.

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