The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

Evolution and Usability of Mobile Phone Interaction Styles

Harri Kiljander

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Computer Science and Engineering for public examination and debate in Auditorium T2 at Helsinki University of Technology (Espoo, Finland) on the 3rd of December, 2004, at 12 o'clock noon.

Dissertation in PDF format (ISBN 951-22-7320-9)   [4995 KB]
Dissertation is also available in print (ISBN 951-22-7319-5)


Over one billion people own or use cellular mobile telephones. Therefore, industry practitioners are faced with a question: how big steps can they take when designing the user interfaces for their new products, or how closely should they stick with the already existing user interface conventions that may already be familiar to the consumers. The objective of this research work is to create and communicate new knowledge for design and usability practitioners about how to design and evolve interaction style conventions in mainstream, voice-centric mobile telephones. In the context of this study, interaction style denotes the framework consisting of the physical interaction objects, the abstract interaction elements, and the associated behavior or interaction conventions that are applied throughout the core functionality of the mobile phone, but excludes the stylistic appearance elements of the user interface.

The main research problem — how do mobile phone interaction style changes affect the initial usability of a mobile phone for users with earlier experience with mobile phones — is approached via several methods. A literature study compares the interaction styles applied in mainstream computing domains against the aspects relevant in the mobile phones domain. A heuristic analysis of contemporary mobile phones is used to formulate an understanding of the available interaction styles and analyze whether there is convergence towards specific types of interaction styles in the industry. An empirical usability testing experiment with 38 test users is conducted with a novel mobile phone interaction style to investigate differences between users who are already familiar with different mobile phone interaction styles.

The study reveals that interaction styles applied in contemporary mobile telephones are designed around menu navigation, and they implement the three primary operations — Select, Back and Menu access — with dedicated hardkeys, context-sensitive softkeys, or using special control devices like joysticks or jog dials. The control keys in the contemporary interaction styles are converging around various two- and three-softkey conventions.

The aspects related to indirect manipulation and small displays pose specific usability and UI design challenges on mobile phone user interfaces. The study shows that the mobile handset manufacturers are applying their usually proprietary interaction styles in a rather consistent manner in their products, with the notable exception of mobile Internet browsers that often break the underlying interaction style consistency.

Based on the results from the empirical usability testing, we claim that despite differences between interaction styles in contemporary mobile phones, users do not face significant difficulties when transferring to a novel mobile phone model.

Keywords: mobile telephone, user interface, interaction style, interface style, usability testing, initial use, learnability

This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.

© 2004 Helsinki University of Technology

Last update 2011-05-26