The studies evaluated interaction performances (i.e., accuracy, time of movements) for interaction with pen or finger, on single or multi touch systems. Seven studies investigated the use of pen based interaction by older users (Charness et al., 2004;
Hourcade and Berkel, 2006; Jastrzembski et al., 2005; Leonard et al., 2005; Moffatt and McGrenere, 2007; Rogers et al., 2005; Wright et al., 2000). The others 27 studies evaluated tactile interaction with users’ fingers. Just one study compared interaction between pen and finger on touchscreen (Hourcade and Berkel, 2006).
Concerning finger interaction, it has been reported that most users used the index finger to point and target selection tasks, as well as text or digit entry tasks. In some studies, experimenters asked subjects to interact with one precise finger (e.g., index) (Jin et al., 2007; Vetter et al., 2011).
Only seven studies evaluated multi-touch gestures of interaction (Apted et al., 2006; Findlater et al., 2013; Harada et al., 2013; Kobayashi et al., 2011; Leitao and Silva, 2013; Lepicard and Vigouroux, 2012; Piper et al., 2010). One study compared single or multi-touch interaction by older users (Lepicard and Vigouroux, 2012). Only two studies analyzed common gestures as scroll, pan, pinch or rotate (Harada et al., 2013; Leitao and Silva, 2013). Multi-touch gestures have only been studied with able-bodied participants.
During the evaluation of gestures for interaction, authors compared the trials’
times and times of completion, as well as accuracy of the gestures (e.g., position inside the target (Harada et al., 2013; Kobayashi et al., 2011), deviation curves (Stößel et al., 2010)) and kinds of errors (e.g., substitution or omission during typing tasks (Nicolau and Jorge, 2012; Wright et al., 2000)).
Table II.9 synthesizes the main gestures of interaction evaluated on the studies we analyzed. For analytical purposes, we divided the gestures identified into two kinds:
target selection, one single touch on one specific target, and displacement, a continuous touch on the screen from an initial to a final position.
Table II.9 HCI studies: Main gestures of interaction in the studies analyzed
Touch
Studies that used/evaluated this interaction technique by older adults
Hourcade and Berkel, 2006; Lee et al., 2012; J. Lee et al., 2009;
(Apted et al., 2006; Findlater et al., 2013; Harada et al., 2013;
Kobayashi et al., 2011; Leitao and Silva, 2013; Lepicard and Vigouroux, 2012; Mertens and Jochems, 2010; Stößel et al., 2010;
Wacharamanotham, 2011; Wood et
(Apted et al., 2006; Findlater et al., 2013; Harada et al., 2013;
Hollinworth and Hwang, 2011;
Kobayashi et al., 2011; Leitao and Silva, 2013; Lepicard and Vigouroux, 2012; Piper and Hollan, 2013)
Discussion about the input modalities in the studies analyzed
Concerning the input modalities identified in the studies we analyzed, most of studies evaluated finger interaction and single touch interaction.
Concerning pen interaction, the study that compared pen and finger describes that finger interaction was more accurate for older adults (aged 65 to 84) even if this group had 88% accuracy for tapping tasks on small targets (16 pixels) with the pen (Hourcade and Berkel, 2006). Indeed, pen-based interaction has been recommended for motor impaired young people because the contact of the pen on the screen seems to be easier to control (Cofre et al., 2012). Besides, contrary to pen, interaction with fingers imply a hidden surface of the screen by the users’ hands (Moffatt and McGrenere, 2007). The accuracy of pen interaction should be investigated with different gestures of interaction (e.g., drag-and-drop) to evaluate the appropriateness of this input modality as an alternative to finger to older users.
Multi-touch interaction is current used on several applications, such as mobile web browsers, photo managers, e-books, maps with different functions like zooming and selection. Although multi-touch interaction requires fine motor control, the seven studies that evaluated multi-touch gestures of interaction for older adults report that subjects were able to accomplish interaction but not without difficulties (Apted et al., 2006; Kobayashi et al., 2011; Leitao and Silva, 2013). Besides, the use of two fingers leads to the occlusion of a part of the screen. Lepicard and Vigouroux (2012) compared single or multi-touch interaction by older users and multi-touch for rotating and zooming tasks resulted in longer times when compared to single-touch (Lepicard and Vigouroux, 2012).
Among the interaction techniques evaluated in the analyzed studies, gestures of interaction based on continuous contact with the screen (e.g., “swabbing”
(Wacharamanotham, 2011), “trabing” (Mertens and Jochems, 2010)) have been designed to improve the accuracy of interaction on touchscreens. Drag-and-drop interaction for older adults has been evaluated only by four studies (Findlater et al., 2013; Kobayashi et al., 2011; Leitao and Silva, 2013; Wood et al., 2005). On resistive touchscreens, it has been considered difficult to execute because of the need of constant pressure between the finger and the screen (Wood et al., 2005). However, on capacitive touchscreens, the continuous contact of the finger with the screen reduces finger oscillation and it has shown effective results for older users with tremor (Mertens and Jochems, 2010;
Wacharamanotham, 2011). Dragging has been preferred to tap for older users (Kobayashi
et al., 2011) even if this gesture is slower for this group of users when compared to tapping (Findlater et al., 2013).
The evaluation of input modalities and interaction techniques can provide recommendations of use for older adults as well as indicate the most suitable interaction technique regarding the needs of the users. On touchscreen devices, interactive systems can be adapted to support different interaction techniques according to the motor skills and special needs of the users. On the other hand, as users can chose between pen and finger as input modalities, interactive systems should be evaluated to allow interaction with pen or finger. More studies need to be done to further understand the difficulties older users find when they execute the gestures of interaction and outline the situations of interaction with touchscreen that might be further supported.