• Currently working toward MA

• BA, University of British Columbia (2005)

Research Interest:

• Usability

• Aging

• Mobile computing

• Human-computer interaction

Current Research:

Attentional Demands of Technology Use

Personal Digital Assistants (PDAs) are powerful and mobile devices, which can be used in distracting environments. The objective of this line of research is to explore whether various tasks on a handheld device (i.e. PDA, smartphone) requires different amounts or different types of attention to perform. Our studies have found that searching through menu layers (navigation) takes more attention than typing in information (data entry).

I am a member of the UBC Aphasia Project working on adapting handheld devices for people with Aphasia in conjunction with the Department of Computer Science at Princeton and UBC, and Department of Speech and Audiology Sciences at UBC. The goal of my line of research is to identify the possible human-related factors that can be used to predict or explain usability problems encountered by senior users of handheld computing devices.

For more information, please visit http://www.cs.princeton.edu/aphasia/.

Past Research:

Viewing Preferences for a High Dynamic Range Display

Novel display technologies are emerging with the potential of much higher contrast and brightness. Despite the growth of display capabilities, it is less known (1) whether viewers can actually perceptually discriminate between these fine levels of brightness, and (2) the properties needed for images to be perceived as realistic and aesthetically pleasant. We conducted a series of studies that developed design guidelines for displays, using a High Dynamic Range (HDR) display as the tool. In the first study, we conducted a psychophysical experiment to specify the just noticeable difference (JND) across luminance levels. In the second study, we selected various images to specify viewers? preference about the perceptual characteristics of a display (i.e. brightness levels, color contrasts). The results from our studies provide a guideline for display engineers to establish first the peak luminance (i.e. brightness) of a display design, by balancing viewer preference against device cost, followed by appropriate choices of contrast ratio and amplitude resolution.

For more information on the High Dynamic Range display and the applications, please visit Brightside Technologies at http://www.brightsidetech.com/

Creation of a Large Set of Haptic Icons

Sensory overload is a common problem with contemporary computer user interfaces, particularly for those that connect users to computation embedded in portable devices and non-desktop environments. These are increasingly pervasive, often have complex functionality, and are frequently used in contexts which pose multiple demands on a single sensory modality: e.g., accessing a cell phone while driving or sitting in a theatre, or using a remote control that requires visual inspection while watching TV. Haptics is another channel whereby information can be used to alert the user of an incoming event in an unobtrusive manner or while other sensory systems are overloaded.

The objective of this project was to design a large set of haptic icons, brief vibratory stimuli that can be used to represent abstract concepts. We conducted a series of psychophysical studies to specify the Just Noticeable Difference (JND) across frequencies, as well as the detection threshold across frequencies with transducers (VBW32 Skin Stimulators from Audiological Engineering Corp. MA). Our haptic icons various on 3 parameters: frequency, amplitude and rhythm. Using a multivariate statistical technique, Multi-dimensional scaling (MDS), we found that all 80 of our icons were distinctly discernible. Agreement on the dissimilarity of the icons was also very consistent across participants. The results from our studies can be directly applicable to mobile devices (e.g. cell phones, PDAs).

For more information on haptics research, please visit the UBC SPIN lab at http://www.cs.ubc.ca/labs/spin/

Cognitive, Sensory, and Perceptual Predictors of PDA Task Performance

Personal Digital Assistants (PDAs) are powerful, mobile devices that are suited for many purposes. For example, for elderly individuals who may be alone, mobility or otherwise impaired or in poor health, a handheld wireless device may provide an escape from isolation, an alternative method for remaining involved and connected, for communicating with friends, relatives, health care providers and others who are crucial to healthy and enjoyable aging. The results from our studies provide guidelines on how to design interfaces that are better adapted to the abilities and needs of the elderly.

The objective of this project was to find out whether cognitive, sensory, or perceptual abilities could be used to predict task performance on a handheld computer. Participants performed a series of tasks a on a handheld computer, which was scored offline according to the guidelines of a manual

Age Differences in PDA Navigation

Previous research addressing training older adults to use technologies has found that older adults make more errors and require more help than younger adults. However, the precise nature of these errors, the cause of these errors, and the relationship between specific error types and help required are unclear. This study explored the possibility that individual differences (i.e. learning style, attitudes towards technology, age) affect the type of errors made, as well as the instructions required to fix these mistakes, in PDA navigation. Videos of key presses and instructions were transcribed into written format, creating a manual that allows reliable scoring of the data, coding the qualitative data into defined categories according to the manual. The results from my study provide guidelines for designing procedures to train older adults in using technologies, according to individual difference factors.

Funding:

• Elizabeth Young Lacey Scholarship in Psychology, UBC (Sept 2005- Aug 2006)

• Graduate Entrance Scholarship (Sept 2005- Aug 2006)

• Undergraduate Scholarship Program (2004)

Research Assistant

June 2004 - Present

     Memory and Cognition Lab, UBC

Teaching Assistant

Sept 2006-Dec 2006

     Psych 333 Instructor: Jonathan Schooler

Sept 2006-Dec 2006

     Psych 302 Instructor: Janet Werker

June 2006-July 2006

     Psych 322 Instructor: Claudia Jacova

Jan 2006-April 2006

     Psych 218 Instructor: Don Wilkie

Sept 2005-Dec 2005

     Psych 217 Instructor: Jeremy Anderson

• Student member of the Canadian Society for Brain, Behaviour and Cognitive Science

• Member of the Golden Key Honor Society

Refereed Contributions

Graf, P. & Li, H. (2006). (in submission). PDA usability differences across the adult lifespan. Journal of Applied Cognitive Psychology.

Other Refereed Contributions

Li. H. & Graf, P. (in submission). Age differences in PDA navigation. The 1st International Conference on Information and Communication Technology and Accessibility.

Li. H. & Graf, P. (in submission). Predicting technology usability problems in the elderly. The 3rd International Conference on Technology, Knowledge and Society.

Li. H. & Graf, P. (in submission). Methodology to assess the attentional demands of using PDAs. IASTED Conference on Human Computer Interaction '07.

Seetzen, H., Li, H., Ye, L., Heidrich, W., Whitehead, L. & Ward, G. (May, 2006). Observations of luminance, contrast and amplitude resolution of displays. SID Symposium Digest of Technical Papers, 37(2), 1229-1233.

Non Refereed Contributions

Graf, P. & Li, H. (July, 2006). Technology usability across the adult lifespan: Practical aspects of cognitive aging. Poster presented at the 19th Annual Cognitive Aging Conference, Atlanta, GA.

Li. H. & Graf, P. (June, 2006). Attentional demands of digital devices. Poster presented at the 16th Annual Canadian Society for Brain, Behaviour and Cognitive Science, Saskatoon, SK.

Li. H. & Graf, P. (May, 2006). Attentional demands PDA navigation and data entry. Poster presented at the 25th Banff Annual Seminar in Cognitive Science, Banff, AB.

Li. H. & Graf, P. (May, 2006). Attentional demands of digital devices. Poster presented at the 8th Annual Northwest Cognition and Memory Conference, Vancouver, BC.

Graf, P., Li, H., & McGrenere, J. (September, 2005). Technology usability across the adult lifespan. Position paper presented at the 19th workshop on Human Computer Interaction and the Older Population, Edinburgh, UK.

Li. H., Lau, L., & Graf, P. (May, 2005). Readabilty of text on a personal digital assistant. Paper presented at the 7th Annual Northwest Cognition and Memory Conference, Bellingham, WA.

Li. H., Lau, L., & Graf, P. (April, 2005). Illumination conditions on reading on a personal digital assistant. Poster presented at the 6th Annual UBC Psychology Students? Association Undergraduate Conference, Vancouver, BC.

Li. H. & Johnston, C. (April, 2005). Impression Management in Responses of the Parent Attribution Test and Parent Locus of Control Scale. Poster presented at the 6th UBC Psychology Students? Association Undergraduate Conference, Vancouver, BC.

Li. H. & Graf, P. (May, 2004). The usability of a personal digital assistant. Poster presented at the 6th Annual Northwest Cognition and Memory Conference, Victoria, BC.