Timing data for the use of a single button

INTRODUCTION

1.1 Aim of Project

The aim of this project was to investigate the variety of ways of using a single button based on different time parameters of button-pressing actions.

1.2 Context of Project

User interactions with complex machine systems now abound: video recorders, hand-held calculators, computers, cars, washing machines are all involve human-machine interaction. The user takes actions such as pressing buttons, moving a mouse or touching a screen. The system responds by initiating operations such as displaying information, activating machinery or performing some other useful service. A button thus is one of the most basic and important items of terminal equipment which enables communication from the user to the machine.

There are many kinds of buttons designed for different machines. Mobile, portable devices such as watches, phones and GPS receivers, are usually limited in the number of buttons that can be attached to them. It is impractical to have a full QWERTY keyboard, and yet there is often a need to be able to input many and complex messages. There are a variety of ways that a single button may be used: a simple-click a double-click, a sustained press (long-click), a triple-click,... But there must be limits. For instance: Are triple-clicks practical? How many different lengths of press are sustainable? The objective of this project was to try to answer such questions.

The study and design of man-machine interaction always combines two disciplines: psychology and computer science. Psychology is concerned with people; computer science with the machinery. Good user interface design requires these two perspectives to be united (Thimbleby, 1990), and interface designers must pay more attention to human factors, including psychology, in order to improve designs. As an interface device, the button is also related to these disciplines when it comes to design and study, but since it is a very small part of interface, little research has been carried out into its use. One exception is The Model Human Processor in Card, Moran and Newell (1983), which provided predictions about the time parameters of button-pressing actions. This project based on this approach, carried out a human experiment to test subjective factors, in order to answer the above questions.

1.3 Structure of the report

Having introduced the context of project, the argument is developed through 5 chapters:

• Chapter 2: There is an overview of the application of buttons in interfaces and their role in their development. Some fundamental issues and questions are also raised.
• Chapter 3-5: Describe a human experiment carried out for this project.
  • Chapter 3 describes the experimental design, including the methodology, the material used and user segmentation, etc.
  • Chapter 4 reports the results of the experiment, the procedure and duration, the response from different user groups, and so on.
  • Chapter 5 discusses the findings of the experiment, answers the questions raised in Chapter 2.
• Chapter 6: Takes a look into the future further research.

FURTHER WORK AND NEW QUESTIONS

At the beginning of this project we stated that those questions about a single button arising in the context of human-machine interaction, and we know that these questions are concerned with both human behaviour and machine behaviour. We therefore try to test some more subjective and uncertain factors of human reaction in this project based on the Model Human Processor.

The experiment focused on timing data collection and some basic analysis of the data. Within the time constraints of the project, it was not possible to do more extensive testing. For example, as mentioned earlier, it would have been better to improve error detection. Hence, the subjective factors have not been fully tested and analyzed. For instance, some users, especially some older users tended to do more carefully; some users seemed to lose patience. Does attitude make a significant different?

High-frequency computer users and non-experienced users did not evenly distribute in different age group, which may have distorted the average performance of each group. Therefore, the comparison based on the experienced and inexperienced user category has not been completed.

One open question is whether and how button-press timings will differ across different machines and types of button. For example, it may take the user different times to press buttons on a mobile phone, a portable computer or a desktop computer.

Another question for interface designer is how to set the a timing range for each type of press for all users, given different age range groups have very different performance.

FURTHER RESEARCH

Based on the results and the discussions of the project, the following are some ideas as to future work directions:

• Development of a set of experimental tasks based on the timing range suggested in this project. (i.e. force users to perform presses according to the timings obtained in this experiment and see how many errors are made).
• Carry out another timing experiment with better error detection.
• Design some tests for the investigation of more subjective factors.
• Investigation of the difference between the experienced and non-experienced users with the same age range. Design and choose different samples for it.
• Development of tests by using different machines for timing data collection. especially, using small devices, such as mobile phone, hand-held translator, etc. Comparison of the data.
• Investigation of the usability of combination of clicks with imposed timing, such as single + double click, single + long click.

Besides the study in use of a single-button, the use of multiple buttons is also an interesting topic. Although has been already much research done on that, further research on multiple buttons with imposed timing for each button may be still needed.

Yanyu Li
(Supervisor Alistair Edwards)

September 2000