Touching tribute

The recent release of products such as Apple's iPhone and the Nintendo DS have resulted in an increasing number of people being exposed to portable devices that involve touch-based interactions.

While this is often perceived as a new and novel element of using these devices, research into touch-based interfaces has been going on for decades. The technology originated in the early 70s when the first transparent touchscreen interface was invented. Since this initial breakthrough, the technology has been incorporated into a number of different settings such as public information devices that provide tourist information, self-service shopping in retail environments and cash and ticket machines.

So why has this technology become so much more prominent in recent years? One of the appealing elements is that it makes interactions with systems much more intuitive — you can point at something on a screen and there is a direct and observable relationship between your finger (or stylus in some cases) and the operations of the system.

This can provide a number of benefits. For example, the improved usability of touchscreen systems helps to explain their popularity in retail environments where there are often high employee turnover rates, and large amounts of time and money has to be invested on training. By utilising such technology, it is possible to train people much faster than would have been possible with traditional point-of-sale systems.

It is also important to highlight the role that cost has played in the increased prominence of touch-based systems. The price of this technology has dropped considerably in recent years and it is no longer excessively expensive and resource-hungry.

Despite the potential enhancements the technology can have on interactions with systems and devices, there remain a number of limitations and issues that still need to be addressed.

For example, there is an ergonomic issue in that touchscreens can place excessive stress on fingers when used for long periods of time. This is often because touch-based interfaces require significant pressure to be placed on flat and hard screens. The use of a pointing device can help relieve the stress on fingers, but these often introduce their own design issues. For example, a stylus can easily be lost or broken. But a pointing device can be more accurate than a finger, which because it is larger can sometimes end up selecting ambiguous areas on the screen.

Given the current trend toward touch-based interfaces, are they likely to replace traditional interaction approaches such as the keyboard and mouse?

This seems unlikely in the foreseeable future. The mouse, for example, is still very useful for many tasks, and attempting to replace it through the use of a touchscreen appears counter-productive. A more practical approach would be to find ways in which these devices can complement each other, so that the combination of the two interaction techniques can provide an enhanced experience.

It is important to remember that touchscreens are novel devices with strengths and weaknesses of their own, and careful consideration must always be given when analysing their potential to improve an interaction.

What then, is the future for touch-based interfaces? One area where much research has been conducted is in the use of tactile touchscreen feedback. That is, a screen that when touched provides feedback via a sensation that mimics the action being performed such as the feel of a button being pressed or a slider moving up and down.

This technology, however, has proved difficult to perfect. When considering how to provide tactile feedback for a key press, it is important to understand how our fingers experience such an event. There are two specific movements that are felt (the key going up and down) and these have to be perfectly synched with appropriate audio to accurately simulate a physical keyboard. While these are significant design issues, research has shown that tactile feedback in touch-based systems can significantly improve user performance and satisfaction.

Another important area is the ability for multiple users to simultaneously manipulate a touch-based interface. An interesting example of this is Microsoft's 'coffee table' Surface computer (

) that enables individuals to collaboratively complete a wide variety of tasks, including sharing photos, planning evenings out and paying restaurant bills.

This application demonstrates that the technology has a very exciting future and the potential to revolutionise the way we interact with computers.