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What Can You Say With Only What Can You Say With Only Three Pixels? Three Pixels?
Christopher Campbell Christopher Campbell
IBM Almaden Research Laboratory IBM Almaden Research Laboratory
Peter Tarasewich Peter Tarasewich
Human Human-
- Computer Interaction Laboratory
Computer Interaction Laboratory College of Computer & Information Science College of Computer & Information Science Northeastern University Northeastern University
Motivations for Research Motivations for Research
- Mobile devices continue to get smaller
Mobile devices continue to get smaller
- Mobility and mobile device use is adding
Mobility and mobile device use is adding to problems of information overload to problems of information overload
- Information management becomes more
Information management becomes more difficult and complex in mobile difficult and complex in mobile environments as well environments as well
- Designing effective interaction methods is
Designing effective interaction methods is a challenging part of HCI, and mobile a challenging part of HCI, and mobile devices make this challenge even greater devices make this challenge even greater
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Technology Focus Technology Focus
Ultra-
mobile devices (UMD)
- Devices that are small enough to be
Devices that are small enough to be comfortably worn by an individual (e.g., comfortably worn by an individual (e.g., watches, bracelets, rings, piercings) watches, bracelets, rings, piercings)
Small screens (if any)
- Can be used in a variety of different contexts
Can be used in a variety of different contexts (i.e., anytime, anywhere) (i.e., anytime, anywhere)
Notification Cues Notification Cues
Notification cues indicate the status or indicate the status or availability of information that is of availability of information that is of interest to a particular user interest to a particular user
Cues convey meta-
information
- Notification cues can be:
Notification cues can be:
- Visual, auditory, or tactile in nature, or any
Visual, auditory, or tactile in nature, or any combination of these (i.e., mixed combination of these (i.e., mixed-
modal)
Public or private
Subtle or intrusive
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Pixel Pixel-
Based Notification Cues
Pixel-
based cues use one or more lights cues use one or more lights (e.g., LEDs) to convey information (e.g., LEDs) to convey information
- This study is part of continuing research
This study is part of continuing research into effective cue design, focusing on into effective cue design, focusing on usability, learning, comprehension, and usability, learning, comprehension, and personalization. personalization.
Previous Study Previous Study
- An earlier experiment evaluated
An earlier experiment evaluated tradeoffs tradeoffs between visual cue display size (number of between visual cue display size (number of lights) and performance (comprehension lights) and performance (comprehension time and accuracy) time and accuracy)
- Each display conveyed the same amount of
Each display conveyed the same amount of information, but differed in the number of information, but differed in the number of lights used, their physical arrangement lights used, their physical arrangement (pattern), the colors used, and whether or (pattern), the colors used, and whether or not the lights blinked not the lights blinked
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Previous Study Findings Previous Study Findings
- There is a tradeoff between performance,
There is a tradeoff between performance, preference, and display size which can be preference, and display size which can be mitigated by effective display design mitigated by effective display design
- Using color, blinking, or binary codes appropriately
Using color, blinking, or binary codes appropriately allows the use of fewer lights to convey a fixed amount allows the use of fewer lights to convey a fixed amount
- f information
- f information
- A linear three
A linear three-
- light design has a balance of good
light design has a balance of good user performance and high user preference, all user performance and high user preference, all within a relatively small footprint within a relatively small footprint
- Tarasewich, Campbell, Xia, and Dideles (2003).
Tarasewich, Campbell, Xia, and Dideles (2003). “ “Evaluation of Visual Notification Cues for Evaluation of Visual Notification Cues for Ubiquitous Computing, Ubiquitous Computing,” ” Proceedings of Proceedings of UbiComp 2003 UbiComp 2003, 349 , 349-
366.
This Study This Study
- Explored two open questions:
Explored two open questions:
- How does learning affect the comprehension
How does learning affect the comprehension and use of the displays? and use of the displays?
- How much information can be effectively
How much information can be effectively conveyed using a given display size? conveyed using a given display size?
Tested linear three-
pixel display, with each pixel displaying one of three colors at one pixel displaying one of three colors at one
- f two intensity (brightness) levels
- f two intensity (brightness) levels
- Users were required to learn five sets of
Users were required to learn five sets of messages of increasing size and messages of increasing size and complexity using the display complexity using the display
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5
Information Conveyed by Cue Information Conveyed by Cue
high, medium, low high, medium, low Priority level Priority level long, short long, short Length Length new, reply, forwarded new, reply, forwarded Type Type email, voicemail email, voicemail Medium Medium family, friends, work family, friends, work Source Source Possible Values Possible Values Category Category
Pixel Attributes Used for Mappings Pixel Attributes Used for Mappings
Same as No. 4, but Same as No. 4, but center center pixel has two pixel has two brightness levels brightness levels 5 5 Same as No. 3, but Same as No. 3, but leftmost leftmost pixel has two pixel has two brightness levels brightness levels 4 4 Each pixel Each pixel either red, blue, or green either red, blue, or green 3 3 Same as No. 1, but Same as No. 1, but two brightness levels two brightness levels 2 2 All three All three pixels either red, blue, or green pixels either red, blue, or green 1 1 Description Description No. No.
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Example Example
- Using Mapping No. 3, these pixels indicate
Using Mapping No. 3, these pixels indicate a forwarded message from friends with a a forwarded message from friends with a high priority high priority
Methodology Methodology
- Tested in laboratory on PCs with 52
Tested in laboratory on PCs with 52 undergraduate and graduate students undergraduate and graduate students
- Starting with No. 1, subjects learned each
Starting with No. 1, subjects learned each mapping to criterion (9 out of last 10 mapping to criterion (9 out of last 10 correct) before advancing to next mapping correct) before advancing to next mapping
- Maximum of 8 seconds to respond
Maximum of 8 seconds to respond
- Subjects paid US$5 for participation only if
Subjects paid US$5 for participation only if entire experiment was completed. entire experiment was completed.
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Testing Environment Testing Environment
Trials to Criterion Versus Message Size Trials to Criterion Versus Message Size
8 10 12 14 16 18 20 1 2 3 4 5 6 7 8 Information (bits) Trials to Criterion
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Time to Criterion Versus Message Size Time to Criterion Versus Message Size
20 40 60 80 100 120 140 1 2 3 4 5 6 7 8 Information (bits) Time to Criterion (seconds)
Mean Number of Errors per Trial Mean Number of Errors per Trial
0.5 1 1.5 2 2.5 3 3.5 4 4.5
So urce Med Type Length P rio rity
Category Mean Number of Errors per Trial Mapping 1 Mapping 2 Mapping 3 Mapping 4 Mapping 5
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Conclusions Conclusions
Overall, micro-
displays can transmit detailed, information detailed, information-
rich messages up to 6.75 bits in size with minimal training 6.75 bits in size with minimal training
- Learning curve fairly level through 4.75 bit
Learning curve fairly level through 4.75 bit messages, then increases steadily messages, then increases steadily
- Place more important information on left
Place more important information on left side of displays side of displays
- What happens if information is not
What happens if information is not structured as much, or at all? structured as much, or at all?
Open Questions Open Questions
- Do these results transfer to actual lights
Do these results transfer to actual lights (e.g., LEDs)? (e.g., LEDs)?
- Would similar results be found using real
Would similar results be found using real devices? In the real world? devices? In the real world?
- What are the effects of having additional
What are the effects of having additional time to learn and use the mappings? time to learn and use the mappings?
- How do these cues affect:
How do these cues affect:
Attention?
- The decision making process?
The decision making process?
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Practical Benefits of Pixel Displays Practical Benefits of Pixel Displays
- Can be used with small and ultra
Can be used with small and ultra-
small devices, ranging from handhelds to devices, ranging from handhelds to watches and jewelry watches and jewelry
- The cues can be sent quietly, without
The cues can be sent quietly, without disturbing others in the environment disturbing others in the environment
- Low power and bandwidth consumption
Low power and bandwidth consumption
- They can be personalized by the user,
They can be personalized by the user, addressing privacy and security concerns addressing privacy and security concerns
- Three red lights on a person’s ring, even when
Three red lights on a person’s ring, even when seen by other people, can convey a message seen by other people, can convey a message
- nly understood by the wearer
- nly understood by the wearer
Current/Future Research Current/Future Research
- Continued validation of pixel
Continued validation of pixel-
based cue designs and principles designs and principles
- Current experiments are testing the effects
Current experiments are testing the effects
- f customization of mappings, cues, and
- f customization of mappings, cues, and
messages on learning and comprehension messages on learning and comprehension
- Prototyping of displays and devices
Prototyping of displays and devices
- Addressing privacy and security issues
Addressing privacy and security issues
Mixed-
mode and multi-
level notification cues
Context-
sensitive cue designs
Mobile Response Teams
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Additional Pixel Studies Additional Pixel Studies
User customized three-
pixel cues preceded by a tactile signal (vibration) sent by a tactile signal (vibration) sent periodically to wireless mobile device periodically to wireless mobile device
- Tarasewich, Bhimdi, and Dideles (2004).
Tarasewich, Bhimdi, and Dideles (2004). “Testing Visual Notification Cues on a Mobile “Testing Visual Notification Cues on a Mobile Device,” Device,” Ext. Abstracts of CHI 2004
- Ext. Abstracts of CHI 2004, 1562.
, 1562.
- Comparison of customized and fixed
Comparison of customized and fixed mappings for a three mappings for a three-
pixel display
- Tarasewich and Campbell (2004). “User
Tarasewich and Campbell (2004). “User Customization of Three Customization of Three-
Pixel Displays,” Ext. Ext. Abstracts of UbiComp 2004 Abstracts of UbiComp 2004. .
Other Research Other Research
- Text entry methods for mobile devices
Text entry methods for mobile devices
- Constrained predictive keypad
Constrained predictive keypad
Touch-
point stylus
Thumbwheel
