7.1 Introduction

Mobile phones were initially developed as strategic communication devices for the military and were then adapted to the needs of mobile businesspeople. The first mobile phones were bulky and designed more for durability and less for usability or desirability (see Figure 7.1; see also Color Plate). In addition to their rather heavy weight, these phones had small displays and buttons with cryptic character-based command labels that were neither intuitive nor in direct reference to variable task sequences. Moreover, interaction with early mobile handsets was mode oriented, which in general has been detected to cause errors and impose a heavy cognitive load on users (Nielsen 1993; Monk 1986).

Figure 7.1: The Mobira Cityman, an NMT phone from the 1980s (left) and the Nokia 6110, a cellular phone from the late 1990s (right).

Since the early 1980s, other user groups have begun to use mobile phones as well. In many parts of the world, mobile phones can now be considered to be consumer products, becoming available for everyone as commodities, which creates totally new usability requirements for mobile handsets. In addition, there is an increasing number of associated telephonyservices that are mostly understood as being part of handset functionality by the users. These services must therefore match the usage experience of handsets in their logic and efficiency.

In the past few years (since about the mid- 1990s), mobile phones...