457 An Evaluation of Finger-Gesture Interaction on Mobile Devices for Elderly Users Christian Stößel, Hartmut Wandke and Lucienne Blessing Keywords: Gesture-based interaction, interface design, aging psychology Abstract Recent years have seen the dissemination of gesture-based interaction elements to an increas- ing number of mass consumer products, most notably finger-gesture interaction on small touchscreen devices. In the present study we investigate whether this new way of interacting with technical devices could be a means of facilitating human technology interaction, particu- larly for older users. This user group is known to frequently face problems when trying to use technical devices, many of them being associated with interfaces which are not tailored to their needs and abilities. In order to find out whether finger-gesture interaction could be a suitable input method also for senior-friendly devices, we compared a group of older and younger users on a set of thirty single-finger gestures on a mobile device regarding speed and accuracy meas- urements. Furthermore, we investigated the effect of different device postures. Results show that older users take more time to perform the gestures, but are in general as accurate as the younger ones. The single-handed operation mode proved to be the most difficult, irrespective of age group. Introduction “Tap is the new click – we’ve entered a new era of interaction design…”, is claimed boldly by Dan Saffer in his recent book “Designing Gestural Interfaces” (Saffer, 2008, p. 3). He points to the fact that in recent years a new way of interacting with technical systems – by means of in- teractive gestures – is being implemented on a steadily growing number of devices. Whether these new possibilities really will affect the way we interact with technology so drastically is yet to be seen. However, there is no denying the fact that since the advent of pioneering de- vices such as the Apple iPhone or the Nintendo Wii, it is today already well established to in- teract with a mobile device by moving the fingers over the display (or trackpad) in certain pat- terns, or by shaking and turning a device to trigger a particular function. Even though there is no exact definition of what counts as gesture-based interaction, and the boundaries to physical manipulation are fluent, we can categorize it roughly into 2-dimensional gestures – usually carried out through finger movements on a touchscreen – and 3-dimensional gestures – usually carried out through hand movements with a device or in front of a camera (Saffer, 2008). Ges- ture-based interaction engulfs all technical devices which can be operated (even if only partly) by means of interactive gestures. As a gesture, in the context of HCI, we understand a “coordi- nated and intended movement of body parts to achieve communication. The information which it contains is specified by the configuration of body parts, the speed and direction of the move- ment and must be interpretable by its receiver.” In our research we focus primarily on finger-gesture input, as this technology is already well established on a huge variety of electronic devices, ranging from mobile phones, PDAs, MP3- Players, digital cameras and navigation systems to laptop and desktop computers. Today, many touchscreen devices can recognize movement patterns of one, or sometimes also several fin- gers, which are then interpreted by the devices and used to trigger functions. For example, by moving two fingers in opposite directions, the user can enlarge pictures or screen sections on the Apple iPhone. While manufacturers don’t hesitate to advertise such systems as being highly intuitive to use, the scientific basis for such claims is still lacking. In particular, this prospect of