Susanne Bay

Mental Models of a Cellular Phone Menu. Comparing Older and Younger Novice Users

The interrelationship between mental models of a cellular phone menu and performance depending on users’ age was under study. The mental representation was assessed through card-sorting technique in 32 novice users (16 aged 20-32, 16 50-64 years). First, they had to process four common tasks on two simulated mobiles enabling online logging of users’ actions. None of the older participants had a correct mental representation of the route to be taken to solve a task, and some were not even aware of the hierarchical nature of the phone menu. Younger participants, in contrast, had a fairly correct mental model. Furthermore, it was shown that the better the mental map of the menu, the better the performance using the device. In conclusion, the awareness of the hierarchical structure of the menu is of central importance to use a cellular phone properly. Therefore, it should be made more transparent to the user.

Landmarks or surveys? The impact of different instructions on children's performance in hierarchical menu structures

Which kind of instruction helps children aged 9-14years interact efficiently with a mobile phone? Due to analogies between navigation in menu structures and the natural environment, three instructions providing different forms of spatial knowledge were under study: A step-by-step instruction featuring landmark knowledge of the menu functions to be selected, a diagram of the menu structure providing survey knowledge and a free exploration of the menu, also giving the children the opportunity to develop survey knowledge. Results show a superiority of the two instructions that provide survey knowledge, except for the youngest children aged 9-10years. This group showed to have lower spatial abilities and is therefore presumably not able to understand and integrate this type of knowledge. For those very young children, the landmark information given in traditional step-by-step instructions is more helpful. It is concluded, that simple diagrams of the menu structure can help children from 11years on to significantly ease their interaction with small menu driven devices.

Effects of Menu Foresight on Information Access in Small Screen Devices

An experiment was conducted to evaluate the effects of menu foresight (the number of menu items visible at a time on the display) on the usability of small screen devices. Cognitive factors (field dependency, locus of control and mental rotation ability) mediating the effects were assessed in order to identify the underlying processes of accessing information. Thirty-nine participants processed tasks on a simulated cellular phone where one, three or seven menu items were presented on the display. Search time, executed steps as well as ratings of the ease of use were collected. Results show that intermediate foresight (three items) led to the best performance. Highly field dependent users showed to have extreme difficulties when only one function was seen on the display whereas low spatial ability participants had most trouble with seven items displayed at a time. These findings suggest that cognitive processes of prestructuring information account for the effects of menu foresight.

Intuitive gestures on multi-touch displays for reading radiological images

Touch-based user interfaces are increasingly used in private and professional domains. While touch interfaces have a high practicability for general daily applications, it is a central question if touch based interfaces also meet requirements of specific professional domains. In this paper we explore the applicability of touch gestures for the domain of medical imaging. We developed a set of intuitively usable gestures, applicable to different screen sizes. The development was entirely user-centered and followed a three-step procedure. (1) The gesture set was developed by asking novices to propose possible gestures for different actions in medical imaging. (2) The gesture set was implemented in a commercial medical imaging solution and (3) evaluated by professional radiologists. The evaluation shows that the user-centered procedure was successful: The gestures did not only work equally well on different screen sizes, but revealed to be intuitive to use or easy to learn.