Editing Touchscreen (section)

==Ergonomics and usage==

===Touchscreen enable===
For touchscreens to be effective input devices, users must be able to accurately select targets and avoid accidental selection of adjacent targets. The design of touchscreen interfaces should reflect technical capabilities of the system, [[Human factors and ergonomics|ergonomics]], [[cognitive psychology]] and [[human physiology]].

Guidelines for touchscreen designs were first developed in the 2000s, based on early research and actual use of older systems, typically using infrared grids—which were highly dependent on the size of the user's fingers. These guidelines are less relevant for the bulk of modern touch devices which use capacitive or resistive touch technology.<ref>{{cite journal|title=ANSI/HFES 100-2007 Human Factors Engineering of Computer Workstations|journal=Human Factors & Ergonomics Society|year=2007|location=Santa Monica, CA}}</ref><ref>{{cite journal|title=Ergonomic Requirements for Office Work with Visual Display Terminals (VDTs)–Part 9: Requirements for Non-keyboard Input Devices|journal=International Organization for Standardization|year=2000|location=Geneva, Switzerland}}</ref>

From the mid-2000s, makers of [[operating systems]] for [[smartphones]] have promulgated standards, but these vary between manufacturers, and allow for significant variation in size based on technology changes, so are unsuitable from a [[Human factors and ergonomics|human factors]] perspective.<ref>{{cite web|url=https://developer.apple.com/library/ios/documentation/userexperience/conceptual/mobilehig/LayoutandAppearance.html|title=iOS Human Interface Guidelines|publisher=Apple|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140826113309/https://developer.apple.com/library/ios/documentation/userexperience/conceptual/mobilehig/LayoutandAppearance.html|archive-date=2014-08-26}}</ref><ref>{{cite web|url=http://developer.android.com/design/style/metrics-grids.html|title=Metrics and Grids|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140716165521/https://developer.android.com/design/style/metrics-grids.html|archive-date=2014-07-16}}</ref><ref>{{cite web|url=http://msdn.microsoft.com/en-us/library/windows/apps/hh465415.aspx|title=Touch interactions for Windows|publisher=Microsoft|access-date=2014-08-24|url-status=dead|archive-url=https://web.archive.org/web/20140826120338/http://msdn.microsoft.com/en-US/library/windows/apps/hh465415.aspx|archive-date=2014-08-26}}</ref>

Much more important is the accuracy humans have in selecting targets with their finger or a pen stylus. The accuracy of user selection varies by position on the screen: users are most accurate at the center, less so at the left and right edges, and least accurate at the top edge and especially the bottom edge. The [[Circular error probable|R95]] accuracy (required radius for 95% target accuracy) varies from {{convert|7|mm|abbr=on}} in the center to {{convert|12|mm|abbr=on}} in the lower corners.<ref>{{cite web|last=Hoober|first=Steven|url=http://www.uxmatters.com/mt/archives/2013/03/common-misconceptions-about-touch.php|title=Common Misconceptions About Touch|publisher=UXmatters|date=2013-02-18|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140826114743/http://www.uxmatters.com/mt/archives/2013/03/common-misconceptions-about-touch.php|archive-date=2014-08-26}}</ref><ref>{{cite web|last=Hoober|first=Steven|url=http://www.uxmatters.com/mt/archives/2013/11/design-for-fingers-and-thumbs-instead-of-touch.php|title=Design for Fingers and Thumbs Instead of Touch|publisher=UXmatters|date=2013-11-11|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140826160836/http://www.uxmatters.com/mt/archives/2013/11/design-for-fingers-and-thumbs-instead-of-touch.php|archive-date=2014-08-26}}</ref><ref>{{cite journal|last1=Hoober|first1=Steven|last2=Shank|first2=Patti|last3=Boll|first3=Susanne|title=Making mLearning Usable: How We Use Mobile Devices|year=2014|location=Santa Rosa, CA}}</ref><ref>{{cite journal|last1=Henze|first1=Niels|last2=Rukzio|first2=Enrico|last3=Boll|first3=Susanne|title=100,000,000 Taps: Analysis and Improvement of Touch Performance in the Large|journal=Proceedings of the 13th International Conference on Human Computer Interaction with Mobile Devices and Services|year=2011|location=New York}}</ref><ref>{{cite journal|last=Parhi|first=Pekka|title=Target Size Study for One-Handed Thumb Use on Small Touchscreen Devices|journal=Proceedings of MobileHCI 2006|year=2006|location=New York}}</ref> Users are subconsciously aware of this, and take more time to select targets which are smaller or at the edges or corners of the touchscreen.<ref>{{cite book|last1=Lee|first1=Seungyons|last2=Zhai|first2=Shumin|title=Proceedings of the SIGCHI Conference on Human Factors in Computing Systems |chapter=The performance of touch screen soft buttons |year=2009|page=309|location=New York|doi=10.1145/1518701.1518750|isbn=9781605582467|s2cid=2468830}}</ref>

This user inaccuracy is a result of [[parallax]], visual acuity and the speed of the feedback loop between the eyes and fingers. The precision of the human finger alone is much, much higher than this, so when assistive technologies are provided—such as on-screen magnifiers—users can move their finger (once in contact with the screen) with precision as small as 0.1&nbsp;mm (0.004&nbsp;in).<ref>{{cite book|last=Bérard|first=François|title=Proceedings of the 2012 ACM international conference on Interactive tabletops and surfaces |chapter=Measuring the linear and rotational user precision in touch pointing |year=2012|page=183|location=New York|doi=10.1145/2396636.2396664|isbn=9781450312097|s2cid=15765730}}</ref>{{dubious|date=December 2017}}

===Hand position, digit used and switching===
Users of handheld and portable touchscreen devices hold them in a variety of ways, and routinely change their method of holding and selection to suit the position and type of input. There are four basic types of handheld interaction:
* Holding at least in part with both hands, tapping with a single thumb
* Holding with two hands and tapping with both thumbs
* Holding with one hand, tapping with the finger (or rarely, thumb) of another hand
* Holding the device in one hand, and tapping with the thumb from that same hand

Use rates vary widely. While two-thumb tapping is encountered rarely (1–3%) for many general interactions, it is used for 41% of typing interaction.<ref>{{cite web|last=Hoober|first=Steven|url=http://uxmatters.com/mt/archives/2014/09/insights-on-switching-centering-and-gestures-for-touchscreens.php|title=Insights on Switching, Centering, and Gestures for Touchscreens|publisher=UXmatters|date=2014-09-02|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140906044746/http://www.uxmatters.com/mt/archives/2014/09/insights-on-switching-centering-and-gestures-for-touchscreens.php|archive-date=2014-09-06}}</ref>

In addition, devices are often placed on surfaces (desks or tables) and tablets especially are used in stands. The user may point, select or gesture in these cases with their finger or thumb, and vary use of these methods.<ref>{{cite web|last=Hoober|first=Steven|url=http://www.uxmatters.com/mt/archives/2013/02/how-do-users-really-hold-mobile-devices.php|title=How Do Users Really Hold Mobile Devices?|publisher=UXmatters|date=2013-02-18|access-date=2014-08-24|url-status=live|archive-url=https://web.archive.org/web/20140826211832/http://www.uxmatters.com/mt/archives/2013/02/how-do-users-really-hold-mobile-devices.php|archive-date=2014-08-26}}</ref>

===Combined with haptics===
Touchscreens are often used with [[haptic technology|haptic]] response systems. A common example of this technology is the vibratory feedback provided when a button on the touchscreen is tapped. Haptics are used to improve the user's experience with touchscreens by providing simulated tactile feedback, and can be designed to react immediately, partly countering on-screen response latency. Research from the [[University of Glasgow]] (Brewster, Chohan, and Brown, 2007; and more recently Hogan) demonstrates that touchscreen users reduce input errors (by 20%), increase input speed (by 20%), and lower their cognitive load (by 40%) when touchscreens are combined with haptics or tactile feedback. On top of this, a study conducted in 2013 by Boston College explored the effects that touchscreens haptic stimulation had on triggering psychological ownership of a product. Their research concluded that a touchscreens ability to incorporate high amounts of haptic involvement resulted in customers feeling more endowment to the products they were designing or buying. The study also reported that consumers using a touchscreen were willing to accept a higher price point for the items they were purchasing.<ref>{{cite journal|doi=10.1016/j.jcps.2013.10.003|title=Tablets, touchscreens, and touchpads: How varying touch interfaces trigger psychological ownership and endowment|journal=Journal of Consumer Psychology|volume=24|issue=2|pages=226–233|year=2014|last1=Brasel|first1=S. Adam|last2=Gips|first2=James|s2cid=145501566 }}</ref>

===Customer service===
Touchscreen technology has become integrated into many aspects of customer service industry in the 21st century.<ref>{{cite journal |last1=Zhu |first1=Ying |last2=Meyer |first2=Jeffrey |title=Getting in touch with your thinking style: How touchscreens influence purchase |journal=Journal of Retailing and Consumer Services |date=September 2017 |volume=38 |pages=51–58 |doi=10.1016/j.jretconser.2017.05.006 }}</ref> The restaurant industry is a good example of touchscreen implementation into this domain. Chain restaurants such as Taco Bell,<ref name="Hueter Swart 1998 pp. 75–91">{{cite journal |last1=Hueter |first1=Jackie |last2=Swart |first2=William |title=An Integrated Labor-Management System for Taco Bell |journal=Interfaces |date=February 1998 |volume=28 |issue=1 |pages=75–91 |doi=10.1287/inte.28.1.75 |citeseerx=10.1.1.565.3872 |s2cid=18514383 }}</ref> Panera Bread, and McDonald's offer touchscreens as an option when customers are ordering items off the menu.<ref>{{cite journal |id={{Gale|A264377887}} |last1=Baker |first1=Rosie |title=FOOD: McDonald's explores digital touchscreens |journal=Marketing Week |date=19 May 2011 |pages=4 }}</ref> While the addition of touchscreens is a development for this industry, customers may choose to bypass the touchscreen and order from a traditional cashier.<ref name="Hueter Swart 1998 pp. 75–91"/> To take this a step further, a restaurant in Bangalore has attempted to completely automate the ordering process. Customers sit down to a table embedded with touchscreens and order off an extensive menu. Once the order is placed it is sent electronically to the kitchen.<ref>{{cite journal |id={{Gale|A269135159}} |title=A Restaurant That Lets Guests Place Orders Via a Touchscreen Table (Touche is said to be the first touchscreen restaurant in India and fifth in the world) |journal=India Business Insight |date=31 August 2011 }}</ref> These types of touchscreens fit under the Point of Sale (POS) systems mentioned in the lead section.

==="Gorilla arm"===
{{see also|Repetitive strain injury|Tennis elbow}}
Extended use of gestural interfaces without the ability of the user to rest their arm is referred to as "gorilla arm".<ref>{{cite web|url=http://catb.org/jargon/html/G/gorilla-arm.html|title=gorilla arm|publisher=Catb.org|access-date=2012-01-04|url-status=live|archive-url=https://web.archive.org/web/20120121023718/http://www.catb.org/jargon/html/G/gorilla-arm.html|archive-date=2012-01-21}}</ref> It can result in fatigue, and even repetitive stress injury when routinely used in a work setting. Certain early pen-based interfaces required the operator to work in this position for much of the workday.<ref>{{cite web|url=http://gesturedesignblog.com/?page_id=19|title=Gesture Fatigue ruined light pens forever. Make sure it doesn't ruin your gesture design|publisher=Gesture Design Blog|access-date=2014-08-23|archive-url=https://web.archive.org/web/20150213011323/http://gesturedesignblog.com/?page_id=19|archive-date=2015-02-13|url-status=dead}}</ref> Allowing the user to rest their hand or arm on the input device or a frame around it is a solution for this in many contexts. This phenomenon is often cited as an example of movements to be minimized by proper ergonomic design.

Unsupported touchscreens are still fairly common in applications such as [[Automated teller machine|ATMs]] and data kiosks, but are not an issue as the typical user only engages for brief and widely spaced periods.<ref>{{cite journal|author=Pogue, David |date=January 3, 2013|title=Why Touch Screens Will Not Take Over|journal=[[Scientific American]]|volume=308|issue=1|page=25|doi=10.1038/scientificamerican0113-25|pmid=23342443}}</ref>

===Fingerprints===
[[File:IPad with extensive fingerprints and smudges.jpg|thumb|Fingerprints and smudges on an [[iPad]] ([[tablet computer]]) touchscreen]]

Touchscreens can suffer from the problem of fingerprints on the display. This can be mitigated by the use of materials with [[optical coating]]s designed to reduce the visible effects of fingerprint oils. Most modern smartphones have [[oleophobic]] coatings, which lessen the amount of oil residue. Another option is to install a matte-finish anti-glare [[screen protector]], which creates a slightly roughened surface that does not easily retain smudges.

===Glove touch===
Capacitive touchscreens rarely work when the user wears gloves. The thickness of the glove and the material they are made of play a significant role on that and the ability of a touchscreen to pick up a touch.

Some devices have a mode which increases the sensitivity of the touchscreen. This allows the touchscreen to be used more reliably with gloves, but can also result in unreliable and phantom inputs. However, thin gloves such as medical gloves are thin enough for users to wear when using touchscreens; mostly applicable to medical technology and machines.