The format for your Thesis/Research project should be in APA format

40 Pages·2015·0.5 MB·English

CALIFORNIA STATE UNIVERSITY, NORTHRIDGE

Landscape Orientation: Handheld Touch Screen Device Interaction

A thesis submitted in partial fulfillment of the requirements
For the degree of Master of Arts in Psychology,
Human Factors and Applied Psychology

By
Richard Kitchen

August 2015
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The thesis of Richard Kitchen is approved:

_______________________________________________ __________________
Dr. Jill Quilici Date

_______________________________________________ __________________
Barry Berson Date

_______________________________________________ __________________
Dr. Tyler Blake, Chair Date

California State University, Northridge
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Table of Contents
Signature Page ii
Abstract v

Section 1: Introduction 1
Input Devices for Mobile Systems 1
Section 2: Related Work 5
Section 3: Current Study 7
Section 4: Research Design 8
Thumbs Used 9
Button Position 9
Reaction Time 9
Convenience 10
Hypothesis 10
Section 5: Methods 11
Participants 11
Facility and Stimuli Requirements 11
Section 6: Procedure 13
Section 7: Potential Design Implications 15
Section 8: Results 16
Reaction Time 16
Errors 18
Convenience 21
Section 9: Discussion 27
Section 10: Conclusion 30
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Works Cited 31
Appendix: Participant Questionnaire 34

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Abstract

Landscape Orientation: Handheld Touch Screen Device Interaction

By
Richard Kitchen
For the degree of Master of Arts in Psychology,
Human Factors and Applied Psychology

This research explored the effects of button position and screen layout of touch screens
on a mobile device. Three dependent variables were measured: reaction time, errors, and
perceived convenience. Thirty participants were required to select a rectangular button
displayed on the device as quickly and accurately as possible. Twenty individual button
locations were used. Button locations were grouped into exterior and interior buttons.
Exterior buttons were around the perimeter of the display while interior buttons did not
come in contact with any edges. Convenience was significantly higher for interior buttons
for both dominant and non-dominant thumb conditions for small, medium, and large
thumb sizes. Implications for touch screen design and layout were discussed.
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Section 1: Introduction
Contemporary mobile devices incorporate high definition touchscreen displays,
communication channels (cellular, Wi-Fi, Bluetooth, etc.), biometric verification, online
access, native applications, cloud storage and access, integration across devices, cameras,
motion and orientation detection, and location awareness capabilities. These technical
capabilities afford users with experiences and abilities such as playing video games,
engaging in social communities, messaging or emailing, downloading and listening to
music, filming and photography, business, learning, shopping, and weather.
The number of mobile devices is increasing rapidly. Global smartphone users
increased from 1 billion in 2012 to 1.75 billion in 2014. An estimated 2.5-billion
smartphone users will exist by 2017 (eMarketer, 2014; Yi, 2013).
The usage of mobile devices is also increasing. As of January 2014, 58% of
Americans owned a smartphone (PewResearch, 2014). Over 1.3 million applications
were available for download through Apple’s ITunes at the beginning of 2015 and over
75 billion app downloads occurred by June 2014 (apptrace, 2015; Perez, 2014).
As both the number of applications employed and the total time spent using them
increase, the need for flexible and efficient control methods becomes increasingly
important. A variety of input control methods (e.g., hard keys, touch screens, voice
inputs, and gestural inputs) are available but data on their relative effects on user
performance with mobile devices is sparse. Design–related information is needed to both
guide the selection of input techniques, and the optimization of design parameters within
each input method.
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Input Devices for Mobile Systems
Hard keys are used on many mobile devices such as Blackberry phones and
Garmin handheld Global Positioning Systems. Hard keys have several advantages: (1)
direct tactile feedback to confirm control actions, (2) familiarity with their use due to the
ubiquity of computer keyboards and devices equipped with hard keys (car stereos,
microwaves, etc.), (3) accessibility when wearing gloves and (4) low power consumption
(Silicon Labs, 2014).
Drawbacks of using hard keys include their limitations in serving multiple
functions and the reduction of display screen size often required to accommodate hard
keys. Designers can minimize these drawbacks through thoughtful design. Foldout
keypads and reduced key size are examples of methods that allow for maximum screen
size. Multifunction keys increase the number of operations that hard keys can perform.
The number of touch screens produced globally is increasing (Canalys, 2010)
(Wu, 2014). Touch screen interfaces are sometimes used along with a hard QWERTY
keyboard or a bank of hard keys to perform common functions. Increasingly, handheld
devices relegate the bulk of user interface tasks to the touch screen and feature very few
hard keys. The entire display is used as the input medium on many handheld touch screen
device. This allows designers to build devices with larger displays because dedicated
hard keys are minimized. Apple’s line of phones and tablets use only four hard keys for
basic functionality while soft keys drive the majority of the experience through the
display. Windows 8, used on touch screen laptops, combines touch input with traditional
keyboards and pointing devices.
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Advantages of touch screen interfaces, aside from the ability to increase display
size compared to devices with hard keys, include the ability to change dynamically in
response to user behavior in order to provide the most appropriate user interface for the
given situation such as using an iPhone for driving directions and zooming in to confirm
upcoming road conditions and selecting a point of interest for more information (J.D.
Power and Associates, 2010).
Drawbacks of touch screens include low precision compared to pointing devices
(e.g., a mouse or stylus), the buildup of fingerprints and dirt on the screen, occlusion of
the screen by fingers during use, high battery usage, poor visibility in sunlight, difficulty
of use by visually impaired users, and the need for special gloves with touch elements
incorporated into the glove.
Handheld touch screen device applications require purposeful and well-informed
design decisions made within the context of the handheld touch screen form factor and
user interaction methods. The limited screen size of handheld touch screen devices
impacts both design decisions and the ability of users to successfully interact with the
application. Simply shrinking down standard desktop applications to fit on handheld
touch screen devices displays fails to address the limiting aspects of the handheld touch
screen device form factor, and leads to a low performing interface or poor user
experiences (Brewster, 2002). The relatively low precision of a finger for touch screen
input requires large enough buttons such that the user selects only the desired touch target
( Karlson & Bederson, 2007; Lee & Zhai, 2009; Park, Han, Park, & Cho, 2008; Parhi,
Karlson, & Bederson, 2006; Perry & Hourcade, 2008). This lack of fine pointing ability
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is most apparent during thumb touch tasks as compared to index finger touch tasks
(Wobbrock, Myers, & Aung, 2008).

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Section 2: Related Work
Research in 2006 by Parhi et al. focused on determining the optimal target size for
one-handed thumb use on a handheld touch screen device. Optimal target size was
determined by time on task, error rate, task hit distribution, and participant preference.
Both discrete and serial tasks were evaluated, while target size and target position were
varied. Participants touched the targets with their dominant thumb while holding the
device with their dominant hand (Parhi, Karlson, & Bederson, 2006). All tests were
performed using a touch screen device configured in portrait orientation. Parhi et al.
found that task completion speed improved as the target size increased from 5.8mm to
13.4mm (the largest size tested). The results showed that error rate improved with
increasing target size as well, but these positive effects appeared to asymptote beyond 9.6
mm for discrete tasks, and beyond 7.7 mm for serial tasks.
The research of Park et al in 2008 gave evidence that users did not complete tasks
with higher performance measures when touching targets that they perceived as more
convenient while using a handheld touch screen device in portrait orientation. They found
that participants rated the center of the screen as most convenient to use even though
actual performance data regarding success rate and number of errors showed that targets
placed along the perimeter of the screen yielded the most effective performance (Park et
al, 2008).
Perry and Hourcade (2008) evaluated one-handed touch tasks using a handheld
touch screen device for use by either the right or left hand. They also looked into the
effects of walking versus standing while completing the touch tasks. They found no
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