“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. Also considered an issue for the iPhone’s capacitive touchscreen was the requirement for user’s fingers to be bare - activation relies on electro-connectivity in the user’s fingers. Where discussed, this was seen as a potential burden during winter months, as gloved users would find their fingers rendered useless, unless fingerless or specialist gloves were worn.

3.4 Form Factor

Referring to issues such as size, weight and shape, the ergonomic aspects of both touch and non-touch handsets have a notable impact on the user experience. For prac- tical reasons, the ideal mobile phone should not impose constraints on the user’s clothing or accessories. The desired size and shape needs to fit comfortably, not only in the hand, but also in pockets and/or the user’s choice of bag. Accordingly, during our studies some participants wanted to place the iPhone in a pocket, to try it out for size. Typically, reactions highlighted that the handset’s physical design achieved a good balance between being a suitable size and weight to be accommodated in bags or clothing with relative comfort, while still offering a screen size optimised for touchscreen interaction, especially when it comes to web browsing. In terms of handling the device there were a modicum of concerns that the iPhone’s overall form factor may be uncomfortable and potentially awkward to use for voice calls, particularly lengthy ones, especially if protected by an attached casing. Also, mixed with positive reviews of the iPhone’s ‘sleek’ hardware design, was a de- gree of mourning that the days of wedging your handset between shoulder and ear, in order to free up your hands, would be at an end with this handset. However, even where considered a little heavier than traditional handsets, the iPhone was largely considered ‘weighty’ in a positive way, with this being perceived as a mark of quality.

3.5 Navigation – The Importance of Simplicity and Consistency

Like their non-touchscreen siblings, it is imperative that touchscreen interfaces aim towards simplicity and consistency throughout the interface, in order to minimise po- tential frustration and allow user expectations to be appropriately managed. If users have problems with finding, selecting and using the most basic functionality, then they will feel negative about the product. With a mobile phone, it is vitally impor- tant to support key functions such as answering or ending a call, creating and accessing text functionality (and email, if available), listening to music (and volume alteration), and accessing the internet, etc. In terms of accessing functionality, the steps involved should be minimised, by keeping access points at a high level. To support users’ naviga- tion, there also needs to be a clear and direct path to the Main Menu or ‘Home’ area. In this respect, the iPhone was typically praised. All applications are accessible from the home screen, creating a shallow menu structure that is practically impossible to get lost in, and the single hard key provides a constantly visible route home. On the negative side, secondary functions of the Home key, such as the ability to double-press this to access Favourite Contacts and its role to exit the menu customization mode, were generally only discovered by accident or word of mouth. “I Love My iPhone … But There Are Certain Things That ‘Niggle’ Me” 425

The iPhone interface follows the Apple philosophy of achieving ease of use through simplicity, limiting the number of options and functions available to make menus as simple as possible. One notable example of a key function where perform- ance was marred was instigating a call. Here, fuelled with anticipation of a dedicated call ‘button’, new users often overlooked the need to press the actual phone number once on the contact details page. Perhaps surprisingly, there were some key functions that even presented difficulties for existing iPhone users – e.g., setting an alarm, dis- covering the ‘pinch’ gesture to zoom, etc. In the pursuit for simplicity, it is noteworthy that several functions, cited as impor- tant by mobile phone users, are omitted from the iPhone. Here, our respondents com- monly complained about the lack of an MMS facility, the inability to forward received messages, no communication concerning the number of characters remaining in an SMS (resulting in recipient frustration over multiple texts), the inability to cut and paste, the lack of flexibility in displaying SMS messages (we’ve observed a love- hate relationship with the chat-style view). Functionality increasingly provided on mobile phones, such as radio, a camera facility complete with flash and zoom abili- ties, as well as an (official) way to record video clips (using the built-in camera), were also missed. Accompanying this last point, several comments highlighted reluctance to ‘tinker’ with the handset in order to explore ‘unofficial’ solutions for core func- tionality, given the perceived high cost of the device. Consistency is, largely, a key attribute of the iPhone interface. For example, once users learn to tap in a text entry field to access the virtual keyboard, this works in the same way across applications. Overall, users reported that elements for onward navi- gation could be distinguished with relative ease, despite some inconsistency in the in- terface being noted. Also, the consistent positioning of back buttons throughout the interface was welcomed. However, consistency does not guarantee good usability. Noteworthy here is that the meaning of the ‘+’ button, which is widely used through- out the iPhone interface to, for example, add configuration set-ups or new notes pages, was not immediately visible or understood by all. For example, users often stumbled when setting an alarm. In this case, the ‘edit’ and/or ‘+’ button was often overlooked, with users expecting to select the field of an existing alarm in order to edit the time. In addition, in some places users need to save their changes explicitly, whereas in other places alterations are saved automatically – e.g. while ringtone set- tings are automatically saved, ‘setting the alarm’ requires users to select ‘Save’ to commit their settings. Where encountered, there was occasional uncertainty and con- fusion about whether or not the performed action had been accepted and confirmed. Even existing iPhone users were sometimes surprised that they needed to save their changes within certain areas of the interface and not others. There seems to be a movement towards automatic saving in mobile interfaces, however, to reinforce this model this needs to be applied consistently across the interface.

3.6 Visual Design

As with non-touchscreen devices, it is important for users to readily understand, at a glance, any iconography presented, especially if it’s not supplemented with a label descriptor. Where icons are relatively abstract or their visibility is reduced (through 426 A. Haywood and G. Boguslawski either their visual design and/or a cluttered display), users will become frustrated if they continually struggle to locate target features. Considering the iconography on the iPhone’s Home screen, the colorful array of default items, as well as downloaded applications, tended to attract positive reviews amongst our respondents, with icons largely regarded as depictive rather than ab- stract. Here, the size and relative spacing of the application icons, and the provision of supplementary labels (under each item) were considered to support both selection as well as an understanding of the functionality presented. In terms of its graphical look and feel, despite adopting a rather limited colour pal- ette, the iPhone tended to attract praise, especially amongst Apple-consumers, with a more ‘jazzy, colourful look’ only being requested by a minority.

3.7 The Virtual Keyboard

If devices exclusively rely on an on-screen keyboard, the aim should be to mirror lev- els of speed and accuracy offered by traditional handsets as far as possible. Also, without a permanently presented physical keypad, clear access to the virtual keyboard is vitally important. Users must not be left wondering how to enter text using the touchscreen. Additionally, it is important to ensure that users can readily change be- tween different text input modes, to support the creation of messages that involve punctuation, numbers and the input of special characters. Representing a common task for mobile users, for some even more important than making or receiving calls; writing and sending text messages and, increasingly, emails, is one aspect where touchscreen mobile devices often come under fire, typi- cally amid concerns that virtual keys are not adequately sized for accurate finger- selection. In this regard, the iPhone is no exception. As our findings suggest, those who use their mobile phone extensively, especially for text entry (e.g. heavy texters or Business users), may have a less smooth transition to touchscreen devices, than more ad hoc or light text users. For this latter group, es- pecially in instances where multi-tap text entry was considered a chore, there were in- dications that performance may even be enhanced, at least in the users’ perception. During our research, the iPhone’s on-screen QWERTY keyboard was largely ap- preciated, as the layout (if not the experience) was familiar from using a computer keyboard. However, although the iPhone’s keyboard fills approximately half the screen, the size of the keys tended to attract mixed reactions, and there were concerns over selection accuracy. Especially for novice users, the keys were often considered too small and there were worries that fingers would span more than one key, increas- ing input errors. Aiming to negate such concerns, the ‘magnification bubble’ of the key selected, was popular, both aesthetically and in terms of supplying feedback, as when using the keyboard users’ fingers occluded their selection. Although users often reported improvements in keyboard comfort as their familiar- ity with the on-screen keyboard increased, there was not widespread confidence that performance could ever match that exhibited on a physical keypad. Reports of being able to type more efficiently and with more accuracy on conventional non-touch de- vices were abound. In particular, those who used their mobile device heavily for email or text messaging perceived a deficit in their performance when using the iPhone’s on-screen keyboard. Indeed, both users of conventional numeric 12-key keyboards (multi-tap and predictive users) and users of hard-key QWERTY “I Love My iPhone … But There Are Certain Things That ‘Niggle’ Me” 427 keyboards, reported frustration at a higher perceived level of entry errors, as well as a reduction in perceived speed, when using the iPhone as compared to prior experience with physical keypads. Also, for respondents who indicated proficiency at multi- tasking when texting on a traditional keypad (e.g. texting whilst watching TV or even while driving!), the need to always attend more to the virtual keypad was anticipated and considered a bind. Also, existing touchscreen users (iPhone and competitor) were seen to lament the ability to enter text one-handed without looking at the screen. Similarly, single- handedly balancing the device and taking a photo using the on-screen button was also found to be tricky, if the desired composition was to be maintained. As frequently found with touch interfaces, the iPhone’s keyboard also came under fire for not being ‘thumb-friendly’, and those with long fingernails often experienced difficulties, espe- cially when inputting text. In this latter case, users’ attempts to initiate their selections using their fingernail much like a stylus were thwarted. At least initially, many users attempted to carry over text entry techniques from using physical keypads. For example, numeric keypad users often attempted a one- thumb approach to typing, while some hard-QWERTY users tried a two-thumb tech- nique. However, after frequently mis-keying due to miscalculating which bit of their digit(s) hit the keyboard first and which character was being selected as a result, it was often reasoned that, until familiarity had grown, single index finger interaction was probably the most efficient method, given the width and spacing of the keys. Due to the above concerns, the ability to change the orientation of the device from portrait to landscape, where available, was deemed very welcome. Some anticipated the ability to access the landscape keyboard universally across the interface and ex- pressed surprise when they realised that horizontal text entry was only available in the Safari browser. With the perception that an increase in horizontal width would im- prove both single-digit and thumb performance, this facility was often requested across applications. Interestingly, even where respondents were iPhone users themselves, none used or reported awareness that letters were only registered once the selected ‘key’ had been released. Additionally, where this strategy was prompted, comments reported that it didn’t feel natural to remove one’s fingers from the screen in order to make a selec- tion, and it was doubted whether adopting this strategy would improve performance. The technique was still seen to strongly rely on feedback via the ‘magnification bub- ble’, and it didn’t remove the need to divide one’s attention between the keying area and the characters accruing in the text field. When considering the iPhone’s text correction facilities, despite potential benefits being acknowledged, initially the auto-correct (and complete) facility was considered to represent part of the problem. Optimal use of this can take a little bit of getting used to, as it requires users to divide their attention between what they are doing with their fingers (i.e. typing) and what is being registered on the screen, as well as what is being suggested in the ‘pop-up fields’. Indeed, reports of sending text messages with ‘odd sentences’ in them, because a suggested word had surreptitiously entered the message, pepper our research. The iPhone’s ‘magnifying glass’ editing feature, which supports corrections earlier in a word or line, was not considered intuitive, even amongst some current iPhone users. Accordingly, when faced with the task of correcting input errors, unless users were already aware of this feature, many expressed frustration that, without an 428 A. Haywood and G. Boguslawski obvious alternative, they needed to delete strings of correct characters in order to ac- cess the place where editing was needed. Once this feature was acknowledged, how- ever, it tended to be widely praised for both its actual function and the aesthetic ap- peal of the magnifier.

3.8 Missing the ‘Tactility’ of the Keyboard

Largely, for both novice users and iPhone users alike, some users lamented the natu- ral haptic response of a physical keypad. In particular, comments highlighted con- cerns that locating specific ‘buttons’ on the hard, uniform touchscreen, required users to stare at the on-screen keys while they typed, which took attention away from the text in the message field. This loss of tactility was cited as a factor contributing to deficits in both speed and accuracy, especially amongst novice users. Comments revealed that the undulating feel of a physical keypad and the ‘click’ of- fered upon selection, supported selection without needing to focus undue amounts of attention on the keypad. Especially for numeric keypad users who regularly use pre- dictive text, the need to make selections from a virtual QWERTY keyboard, without any haptic support to signal the relative positioning of the keys, was considered daunting by some. Whilst this discussion has focused on the keyboard, problems associated with a lack of tactile feedback extend to other direct selections. In the absence of a tactile re- sponse, the careful design and placement of visual feedback become more important. The problem with visual feedback on small screens is that fingers occlude parts of the screen (including the elements under selection). With this in mind, users welcomed that, in Safari, feedback appears at the top of screen when a page is loading. Simi- larly, the magnification bubble that provides feedback as users explore the keyboard, was often thought to be both ‘funky’ and informative. With touchscreen interfaces, there is obviously scope for attempting to replicate the haptic feedback offered by a physical keypad by introducing tactile sensations (potentially synchronized with sound). However, despite the argument that providing vibro-tactile effects, corresponding to the user's exploration and selection, will pro- vide a more satisfying user experience, at this stage a lot seems to depend on the so- phistication of the haptic technology. Indeed, our research suggests that offering a range of discrete sensations, such as the realistic feel of buttons depressing and releas- ing, in addition to the feel of a screen populated with icons and the sensation of an undulating keypad, may hold more appeal than a coarse ‘buzz sensation’ whenever a selection is made. Furthermore, regardless of the treatment offered, it is important that users are given the freedom to turn this facility on or off, as preferred.

4 Best Practice Guidelines

Based on our research in this arena, this paper concludes with a range of best practice guidelines for finger-operated touchscreen interfaces. Being focused, rather than ex- haustive in scope, the guidelines indicate factors that are important to consider when evaluating or designing touchscreen solutions for small screen devices. “I Love My iPhone … But There Are Certain Things That ‘Niggle’ Me” 429

Table 1. Best practice guidelines for finger-touch interfaces

Screen size matters • When it comes to touchscreens, screen clarity and size matters - large good quality screens are essential to provide space for key elements. • As larger screens can foster concerns over vulnerability, the hardware design needs to support notions of robustness and quash any concerns over screen fragility. Touchscreen responsiveness • Aim towards high system responsiveness, as delays will frustrate and confuse users. Minimising response lag will dissuade users from pounding the keys to repeatedly select target elements, and/or using their fingernail or pen like a stylus. • To minimise keying errors, ensure that sensitivity and screen alignment (calibration) are optimised. Maximise sensitivity levels, uniformly, across all areas of the screen. Particu- larly where a scroll bar draws the users’ focus, sensitivity at the perimeter needs to be op- timised. Towards a tactile experience • As the tactile experience offered by conventional keypads, may offer a positive effect on efficiency, error rates, and user satisfaction, consider options to support a more tactile user experience – e.g. tactile output for the identification of controls and/or vibro-tactile sensations to in response to selections. • Aim towards an array of discrete sensations, rather than just a coarse ‘buzz sensation’ upon selections. • If provided, tactile feedback should be an optional rather than a default feature, with a means to easily switch between the two modes being understood and clearly visible. Navigation & efficiency of use • If users have problems with the most basic functionality, then they will feel negative about the product. Support key functions such as answering or ending a call, instant mes- saging, listening to music, viewing messages, accessing the internet, etc. • Minimise steps to access or perform core functions, by keeping access points at a high level. • Allow clear and direct navigation to return Home and to the Main Menu. This is espe- cially important where the device doesn’t offer a physical button dedicated to this. • To reassure users and allow ease of navigation, ensure consistency throughout the inter- face. • As users’ fingers may occlude parts of the screen (including selected items), carefully consider the design and placement of visual feedback. Ideally, feedback should appear above the item selected. • Consider ways to ensure navigation and selection are easily discernable, so that users don’t accidentally make selections when they scroll. • Allow actions to be readily reversible, so that if an error is made, it can be easily recti- fied. • As appropriate, consider providing on-screen buttons that can be readily selected and hidden when not required, and ensure that the existence (and access to) these buttons is understood. • Although a help facility mustn’t be seen as the solution to a poor user interface, if feasi- ble, consider options to provide an on-device Help system that is both easy to find and use.

430 A. Haywood and G. Boguslawski

Table 1. (continued)

The virtual keypad • Aim towards mirroring the levels of speed and accuracy offered by traditional handsets as far as possible. • Without a permanently presented keypad, clear access to the virtual keyboard is vitally important. Consider using a consistent convention across the interface (e.g. tapping the field). • Consider presenting a virtual QWERTY keyboard instead a multi-tap configuration (where characters are shared on individual keys). Without the tactile cues familiar on a conventional keypad, a QWERTY layout may be easier to use than a multi-tap design – with the latter, lag and precision issues may come to the fore. • Consider the option to offer the keyboard in a horizontal view, and allow this to be con- sistently available across the interface. • Ensure users can change between different text input modes with ease. Options to enable and disable predictive text and switch between letter, number or symbol inputs, must be clearly presented and quick to use, with any shortcuts being clearly understood. • As users need to feel confident that selections will have the desired effect, ensure the se- lectable area (icon/button) is larger than the target or of an acceptable size. Remember people will want to reach for a stylus if things go wrong or if they don’t feel confident that their selection will be accurate. • As well as being sized to accommodate finger-input, users need to perceive keys and other screen elements to be adequately sized for accurate selection. Explore ways to minimise concerns about finger size relative to key size. Maximise the perceived size of elements, through visual design, ensuring that a good delineation of keypad elements is presented. • Also, to minimise mis-selection ensure that sufficient space between entries in a vertical list. Icons & labeling • Carefully consider iconography. Make use of familiar icons (and colour conventions) so users can associate with them. • Consider colour icons that have detail to them to make the most of graphical capabilities. • Aim towards a high contrast between discrete touch elements, text, and background col- ours. Also, to enhance visibility, controls and text should not be placed over an image or patterned background. • Where icons are relatively abstract, users will become frustrated if they continually strug- gle to locate and use target features (e.g. without a physical key, ensure that the means to end a call is highly visible). While preserving a non-cluttered display, consider supple- menting graphical symbols (such as icons) with labeling or other textual cues. • To aid legibility on small screens, especially across lighting conditions, consider adopt- ing a sans serif font for all text and labels. • Labels and instructions should be short and simple, with abbreviations avoided, if possi- ble. • Allow icons to be suitably sized and spaced, so they can to be readily selected without worrying about accidental selection of nearby icons/screen elements.