“I Love My iPhone … But There Are Certain Things That ‘Niggle’ Me” Anna Haywood and Gemma Boguslawski Serco Usability Services, London, United Kingdom [email protected], [email protected] Abstract. Touchscreen technology is gaining sophistication, and the freedom offered by finger-based interaction has heralded a new phase in mobile phone evolution. The list of touchscreen mobiles is ever increasing as the appeal of ‘touch’ moves beyond the realms of the early adopter or fanboy, into the imagi- nation of the general consumer. However, despite this increasing popularity, touchscreen cannot be considered a panacea. It is important to look beyond the promise of a more direct and intuitive interface, towards the day-to-day reality. Based on our independent research, this paper explores aspects of the touch- screen user experience, offering iPhone insights as examples, before presenting key best practice guidelines to help design and evaluate finger-activated touch- screen solutions for small screen devices. 1 Introduction Although ‘touch’ is the latest buzzword, touchscreen technology and devices have been in use for over ten years, from public systems such as self-order and information kiosks, through to personal handheld devices such as PDAs or gaming devices. As the technology gains sophistication and teething problems are worked on, the list is ever increasing. However, it’s only since touchscreen heralded a new phase in mobile phone evolution with the freedom of finger-based interaction, that ‘touch’ has taken hold of the general consumers’ imagination. Mobile phones by their very nature are intended to support communication and, in- creasingly, access to information while on the move. Technology intended for mobile use needs to map users’ needs without imposing unnecessary constraints. Accord- ingly, it is important to ask whether the much-discussed touchscreen interface is both useful and usable for the mobile user. Does it really live up to expectations, providing a more direct and inviting interaction, which matches users’ day-to-day activities without imposing unnecessary constraints? In an ongoing programme of research into finger-based touchscreen interfaces for mobile devices, which incorporates user studies (with existing touchscreen users and novices), expert reviews, and anecdotal evidence, Serco Usability Services have ex- amined many of the latest touchscreen mobiles in order to identify overall ease-of-use factors and usability issues associated with touch interfaces for small devices. Drawing from this body of research, this paper explores aspects of the users’ ex- perience, offering research into the iPhone as an example, before presenting a range of key best practice guidelines to help design and evaluate finger-activated touchscreen J.A. Jacko (Ed.): Human-Computer Interaction, Part I, HCII 2009, LNCS 5610, pp. 421–430, 2009. © Springer-Verlag Berlin Heidelberg 2009 422 A. Haywood and G. Boguslawski solutions. Although focused rather than exhaustive, the guidelines aim to optimise the user experience by bringing qualities such as simplicity and ease of use, as well as con- sistency and responsiveness to the fore. 2 Perhaps ‘Cool’ But Not a Panacea Within the touchscreen arena, Apple’s iPhone is often the first device that springs to mind when asked to name a touchscreen mobile phone, despite manufacturers such as Samsung, Motorola and LG also being very strong contenders in the touch market- place. Especially since the advent of the Apple’s 3G iPhone, interest in touchscreen mobiles has received a boost. A wealth of competitor products are hitting the market in order to ride on the iPhone wave, each aiming towards the large screen size and aesthetic appeal of the iPhone, while looking to distinguish themselves sufficiently, so not to attract a ‘me-too wannabe’ label or being too iPhone-esque to risk a costly legal battle. Despite its increasing popularity and the promise of a more intuitive interface, touchscreen is not a panacea. While finger-activated touchscreen can arguably be considered a progression over stylus-manipulation, views promoting touchscreen as a natural progression for mobile phones in general, are on ‘shaky ground’. All things being considered, it cannot be considered the ‘cool solution’ that waves goodbye to the usability issues typically associated with traditional, non-touch handsets. In addi- tion, touchscreen devices can bring their own usability problems. At least for now, even Apple’s iPhone, which is often heralded as a touchscreen success story, is by no means perfect. Indeed, often tales of ‘iPhone love’ have user experience issues in the subtext, upon further investigation. 3 Exploring the ‘iPhone Experience’ 3.1 The Transition to ‘Touch’ The iPhone is frequently touted as being more intuitive than other mobile devices, not merely by virtue of its touchscreen interface, but also because it relies on one top- level menu and a single physical button. Additionally, the device is often considered to offer a good balance between flashy design and practical functionality. This ‘bal- ance’ is often cited as adding to its emotional appeal, especially amongst the con- sumer rather than the business market. While there’s a degree of truth in the ability of novice users to adapt relatively quickly to its use, this cannot be held true across the interface. There are aspects of the iPhone’s interface that still have a ‘learning curve’, requiring familiarisation and patience before an acceptable degree of performance is attained. For example, users sometimes struggle to discover and perform gesture style interactions such as zoom- ing. Typically, ‘mastery’ and the overall user experience is measured in comparison to previous mobile phone use, including non-touchscreen devices. Although the tran- sition to touch isn’t always ‘rosy’, the iPhone is often heralded as revolutionary in in- stances where prior mobile use was constantly fraught with difficulties and building the mental model necessary to use the device, was not easy to attain. As an example from our research, after persistently struggling with non-touch devices over several “I Love My iPhone … But There Are Certain Things That ‘Niggle’ Me” 423 years (and multiple handsets), one 73 year old respondent reported being a total iPhone devotee who regularly texts, downloads applications, and is addicted to play- ing games on her beloved iPhone. The interaction paradigm offered by the iPhone is often considered to add to its in- tuitive nature. Here, rather than adopting a computer-based model of scrolling (like some competitors) where a scroll bar sits to the right of the screen, the iPhone’s phys- ical interaction model (i.e. scroll up to access content further down the page and vice versa) encourages users to freely scroll anywhere on the screen. This model allows users to focus on page content and maximises screen real estate. In our studies, many users indicated that dragging a list/page up or down felt very smooth and very much like interacting with a real, physical object. In particular, the ability to flick a list in order to scroll it with momentum was appreciated once mastered. 3.2 Touchscreen Responsiveness Working to minimize the touch-response lag is imperative to the usability of touch- screen interfaces, as delays will frustrate and confuse users, encouraging repeated selection of target elements. Optimising responsiveness will dissuade users from pounding the screen and/or attempting to use their fingernail or pen like a stylus. When users’ reactions to the responsiveness of the iPhone were probed, responses typically signaled a high degree of satisfaction. Responsiveness was thought to be ex- tremely good, with a negligible amount of lag between selection and launch. Indeed, with its underlying capacitive technology, the iPhone was generally considered more re- sponsive than competitor devices that relied on direct pressure (resistive): only the lightest touch was required. However, where novice users were concerned, the iPhone’s high degree of sensitivity sometimes fostered niggling concerns about accidental inter- actions, for example, where overall finger size exceeded the target’s dimension or when hitting the target off-centre. Also, due to its responsiveness, an ongoing problem with the iPhone was that it sometimes confused navigation with selection, if users scrolled too slowly across a webpage full of links. This issue was then compounded by the in- ability to stop a new page opening. 3.3 Screen Size Matters In addition to the inherent novelty appeal, the ‘no-button’ design of touchscreen phones lends itself to a large screen size and the potential for a more sleek aesthetic de- sign not ‘burdened’ by the need to accommodate physical buttons. When it comes to touchscreens, screen clarity and size matters. Large good quality screens are considered essential to provide space for key elements, as well as affording comprehension of the elements presented. Users need to feel that icons and other screen elements are large enough to select without accidentally selecting adjacent items. The hardware design of the iPhone is seen to bolster its emotional appeal. As noted by our respondents, the large 3.5-inch screen size, the clarity of the touchscreen, and its ‘unfussy’ single button design, positively combine, contributing to perceptions of the iPhone as being a high-end phone. Indeed, such factors were cited as reasons why current iPhone users had chosen the iPhone over the competition in the first place. For some novice users, however, positive reactions to the large screen were some- times pitted against concerns that the screen may be vulnerable to damage, which may 424 A. Haywood and G. Boguslawski render the device inoperable. With its reliance on finger-activation, the large iPhone screen was also viewed as a ‘finger print trap’, and novice users sometimes ques- tioned whether the screen would depreciate in sensitivity, especially for scrolling ac- tivations, due to a build-up of dirt and grime on the screen.