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The Effects of Touch Screen Technology on the Usability of E-Reading Devices

Eva Siegenthaler, Yves Bochud, Pascal Wurtz, Laura Schmid, and Per Bergamin

Journal of Usability Studies, Volume 7, Issue 3, May 2012, pp. 94 - 104

Article Contents


Introduction

By the end of September 2010, 11 million Americans were expected to own at least one digital reading device (Fowler & Baca, 2010). U.S. e-book sales grew 183% in the first half of 2010 compared with the year-earlier period, according to the Association of American Publishers (Fowler & Baca, 2010). E-reading is a trend. There are many advantages associated with an e-reading device; for example, you can carry an almost endless number of e-books with you, or you can search the e-book for keywords to locate information quickly. Two different types of e-reading devices are prevalent: dedicated e-book readers (such as the Nook Reader, the Kindle Reader, the Kobo Reader or the Sony Reader, which all use e-ink screen technology) and tablets. E-ink technology has low power consumption, thereby increasing battery life and allowing for a more lightweight device. For example, the new Kindle reader can run up to a month with one battery charge. Another advantage is that e-ink devices can be used outside without glare being a big issue. E-ink displays almost look like printed paper. However, e-ink screens have some disadvantages, most of them are black and white and the pages do not refresh as quickly as devices with an LCD screen. E-ink screens are not illuminated, which means you cannot read in the dark, and you must depend on an external light source. E-ink e-readers are specialized e-reading devices, and they are limited to reading. By contrast, tablet-PCs (tablets) are small computers; their use is not limited to reading. The LCD screens found on all tablets (and the Nook Color e-ink reader) are color displays. But those advantages have downsides: The reflective screens on LCD tablets have higher power consumption, most of the devices are quite heavy, and the glass-like display surface makes it hard to read in bright light. However, it has been reported that under artificial light conditions that are often present in offices or living rooms, expected differences in reading behavior can vanish (Siegenthaler, Wurtz, Wyss, & Bergamin, 2012; Siegenthaler, Bochud, Bergamin, & Wurtz, 2012). Reading is the main function of e-ink readers and also an important function of tablets. Previous studies show that the legibility of text, as presented on specialized electronic reading devices, is comparable to printed paper under specific light conditions for both short term reading and reading over extended periods of time (Siegenthaler et al., 2012). Some of the results even show an advantage for electronic reading devices over classic paper books (Siegenthaler et al., 2012). Previous results also demonstrated that new functions in electronic reading devices, such as font size adjustment, increase legibility (Siegenthaler, Wurtz, Bergamin, & Groner, 2011). Furthermore, the results show that a critical factor for perceived legibility is the usability of the device. If readers have problems with the handling of a device, they will not like reading with it (Siegenthaler et al., 2010). Therefore, easy handling can be a critical factor for the reading experience. One important feature seems to be the touch screen. A touch screen tends to be very intuitive and saves space as no keyboard or mouse is required, which also tends to make for easier hand-eye coordination than a mouse or keyboard. All tablets (iPad, Android, Blackberry, etc.) are operated through a touch screen interface. Originally, e-ink readers didn’t have touch screens; however, many of the newer e-ink devices are equipped with touch screens, but there are still popular e-reading devices without touch screens. Nonetheless, e-ink devices (Sony PRS-600, Neonode's optical touch screen technology) do not have the same sensitivity and reaction time as tablets (iPad, multi-touch TFT-LCDs). But the question remains: Do touch screens enhance the reading experience? If yes, is the sensitivity of the touch screen important? Is the interaction with a multi-touch display more usable for the user? Does it really provide a more direct and inviting interaction with the device?

A previous study has shown that readers have some difficulties when using e-ink reading devices without a touch screen (Siegenthaler et al., 2010). But there are only a few empirical studies about the usability of specialized e-reading devices. Nielsen (2009) tested the Kindle 2 Reader (e-ink-reader, without a touch screen). He noted problems in navigation and criticized the navigation of Kindle 2 as non-intuitive. He concluded that reading non-linear texts (like newspapers) is not comfortable on the Kindle 2. However, he noted that the Kindle 2 was well suited for linear texts (Nielsen, 2009). In general, Nielsen found some advantages in the use of e-readers, like the low weight or the possibility to adjust font size. Also equal-to-print legibility and the multi-device integration were mentioned as a benefit (Nielsen, 2009). Other studies that investigated the usability of specialized reading devices (e-ink reading devices) in an applied field found that users have problems in the handling of the current e-ink reader generation (Lam, Lam, Lam, & McNaught, 2009; McDowell & Twal, 2009; Thompson, 2009). Empirical studies on the usability of tablets are sparse. A German research institute (Phaydon) tested the usability of the Apple iPad (multi-touch) with 18 users (Oberg, 2010). Their results suggested that the Apple iPad could be used intuitively and easily. Another conclusion was that the Apple iPad is good for reading because of its navigation via touch screen, the possibility of adjusting background illumination, the ability to adjust the font size, and because of the search functions. Users also liked the design of the Apple iPad. But the users disliked the reflections on the display depending on the position they held the device (Oberg, 2010). In another study on touch screens, Haywood and Reynolds (2008) found that touch screen delays frustrated and confused users. Developers of touch screen technology should maximize sensitivity levels, uniformly across all areas of the screen, to improve a user’s experience. They also found that if users have problems with the most basic functionality, they would feel negative about the product.

To summarize so far, previous studies do not clearly answer the question whether touch screen technology significantly enhances the usability of e-reading devices. There is some evidence that touch screen interfaces could improve the usability, but because there is no study with a direct comparison of the devices, this remains speculative.

For this reason, we developed a study in which we investigated the usability of three e-reading devices. We compared two e-ink-readers, one with a touch screen and one without a touch screen, and one tablet with a multi-touch display. The usability measures that we used were completing different use cases for each device, asking participants to provide subjective ratings about each device, and asking participants to complete questionnaires about their experiences with each device. We hypothesized that touch screens contribute to the improvement of the usability of an e-reading device. Furthermore, we hypothesized that the sensitivity of a touch screen has a positive influence on the usability.

 

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