Designing for Kiosks

On the surface, kiosks may appear to have much in common with desktop interfaces: large, colorful screens and reasonably beefy processors behind them. But as far as user interactions are concerned, the similarity ends there. Kiosk users, in comparison with sovereign desktop application users, are at best infrequent users of kiosks and, most typically, use any given kiosk once. Furthermore, kiosk users will either have one very specific goal in mind when approaching a kiosk or no readily definable goal at all. Kiosk users typically don't have access to keyboards or pointing devices, and often wouldn't be able to use either effectively if they did. Finally, kiosk users are typically in a public environment, full of noise and distractions, and may be accompanied by others who will be using the kiosk in tandem with them. Each of these environmental issues has a bearing on kiosk design.

Kiosk posture and navigation

Because kiosks are used infrequently by any one user, and typically for a relatively brief span of time, kiosk interfaces should be weighted towards the transient posture described in Chapter 8. This means large, colorful, engaging interfaces with clear affordances for controls, clear mappings between hardware controls (if any) and their corresponding software functions, and minimal required navigation. As in the design of handhelds, floating windows and dialogs should be avoided; any such information or behavior is best integrated into a single, full screen (as in sovereign-posture applications). Kiosks thus tread an interesting middle ground between the two most common desktop postures.

Because kiosks often guide users through a process or a set of information screen by screen, contextual navigation takes on more importance than global navigation. The important navigational paradigm becomes "Where can/do I go from here?" rather than simply "Where can I go?" This said, it's important for kiosks whose primary purpose is transactional (see below) to provide escape hatches that allow users to cancel transactions and start over at any point.

Transaction versus exploration

Kiosks generally fall into two categorical types: transactional and explorational. Transactional kiosks are those that provide some tightly scoped transaction or service. These include bank machines (ATMs), ticketing machines such as those used in airports, train and bus depots, and some movie theaters. Even vending machines can be considered a simple type of transactional kiosk. Users of transactional kiosks have very specific goals in mind: to get cash, a ticket, a Tootsie Roll, or some specific piece of information. These users have no interest in anything but accomplishing their goals as quickly and painlessly as possible.

Explorational kiosks are most often found in museums. Educational and entertainment-oriented kiosks are typically not a main attraction, but provide additional information and a richer experience for users who have come to see other, possibly (but not necessarily) related exhibits. Explorational kiosks are somewhat different from transactional kiosks in that users typically have few expectations when approaching them. They may be curious, or have a vague desire to be entertained or enlightened, but have little in the way of end goals in mind. For explorational kiosks, it is the act of exploring that must engage the user. Therefore, the kiosk's interface must not only be clear and easy to master in terms of navigation, but it must also be aesthetically pleasing and visually (and possibly audibly) exciting to users. Each screen must be interesting in itself, but also encourage users to further explore the system.

Interaction in a public environment

Transactional kiosks, as a rule, require no special enticements to attract users. However, they do need to be placed in an optimal location to both be obviously visible and to handle the flow of user traffic they will generate. Use wayfinding and sign systems in conjunction with these kiosks for most effectiveness. Some transactional kiosks, especially ATMs, need to take into account security issues: If their location seems insecure (or is in actuality), users will avoid them or use them at their risk. Architectural planning for transactional kiosks should occur at the same time as the interaction and industrial design planning.

As with transactional kiosks, place explorational kiosks carefully and use wayfinding systems in conjunction with them. They must not obstruct any main attractions, and yet must be close enough to the attractions to be perceived as connected to them. There must be adequate room for people to gather: Exploration kiosks are more likely to be used by groups (such as family members). A particular challenge lies in choosing the right number of kiosks to install at a location—companies employing transactional kiosks often engage in user flow research at a site to determine optimum numbers. People don't linger long at transactional kiosks, and they are usually more willing to wait in line because they have a concrete end goal in mind. Explorational kiosks, on the other hand, encourage lingering, which makes them unattractive to onlookers. Because potential users have few expectations of the contents of an explorational kiosk, it becomes difficult for them to justify waiting in line to use one. It is safe to assume that most people will only approach an explorational kiosk when it is vacant.

When designing kiosk interfaces, carefully consider the use of sound. Explorational kiosks seem naturals for use of rich, audible feedback and content, but volume levels should be chosen so as not to encroach on the experience of the main attraction such kiosks often support. Audible feedback should be used sparingly for transactional kiosks; but it can be useful, for example, to help remind users to take back their bankcard or the change from their purchases.

Managing input

Most kiosks make use either of touch screens or hardware buttons and keypads that are mapped to objects and functions on the screen. In the case of touch screens, the same principles apply here as for other touch screen interfaces:

• Touchable objects should be large enough to be manipulated with a finger, high contrast, colorful, and well separated on the screen to avoid accidental selection.

• It may be tempting to make use of an on-screen keyboard for entering data on touch screen kiosks. However, this input mechanism should be used as a last resort—when, for example, an arbitrary code is required (a keypad may be more effective for this, too) or some other information that can't reasonably be chosen from a list.

• Drag and drop should be avoided as an idiom, and scrolling of any kind should be avoided on kiosks except when absolutely necessary.

Some kiosks make use of hardware buttons mapped to on-screen functions in lieu of touch screens, which are more expensive and more prone to malfunction. As in handheld systems, the key concern is that these mappings remain consistent, with similar functions mapped to the same buttons from screen to screen. These buttons also should not be placed so far from the screen or arranged spatially so that the mapping becomes unclear (see Chapter 11 for a more detailed discussion of mapping issues).