Areas of Research

My research interests stem from the underlying question: how would human cognition and knowledge be different with different senses? In particular, each sense emphasizes certain environmental features (e.g., faces, texture, color, and temperature), and provides a mental framework for dealing with abstract concepts (e.g., visual imagery, mathematical charts).

My research falls into two scientific areas: (1) haptic perception and (2) visual impairment. As a haptic scientist, my interest in visual impairment is motivated by the extraordinary haptic abilities of people who are blind. As a visual-impairment scientist, my interest in haptics can be explained by the importance of haptic technologies for accessibility. A third area of research is (3) developing methodologies that support my other research, including but not limited to developing finger-tracking technologies, statistical models of finger-movement trajectories, and haptic stimuli/materials.

Haptic Perception

The majority of my research projects investigate the characteristics of haptic perception.

  1. What are the important cues for haptic perception?
    • What are cues' relative importance depending on the task and the person's abilities?
    • What part of the hand/arm do cues operate on?
    • How quickly can cues be estimated and a value change be detected?
    • How is a single cue integrated across the fingers and parts of the hand?
    • How do multiple haptic cues combine, and how do they combine with auditory and/or visual cues?
  2. How are exploratory procedures (EPs), specific movement patterns over specific object parts using specific hand areas, used to extract haptic information?
    • How do EPs vary depending on the task, cues extracted, and the person's abilities?
    • Are the EPs that are used "optimal," predictable based on a mathematical principle?
    • How can EPs be captured, modeled, and predicted?
  3. How does cue perception and EP use develop, change with experience, and differ between individuals?

Haptic Perception & Psychophysics

Many of my research projects investigate the characteristics of haptic perception using typical perception/psychophysics paradigms. These projects compare how people perform at various perceptual tasks, such as haptic search or haptic distance measurement. The experiments often vary which fingers participants use and investigate differences for participants who do and do not have visual impairments.

Finger-Movement Trajectories

Finger-movement trajectories may be as valuable to haptic science as eye movements have been to vision science. Unlike eye movements, where information is suppressed during a movement and can therefore be regarded as a series of fixations, haptic perception is not suppressed during movement and therefore must be considered as trajectories. Various projects investigate how to capture, characterize, model, and predict finger-movement trajectories.

Haptic Interfaces

The design of haptic interfaces can be based off existing visual interfaces. Alternatively, these interfaces could be based off first-principals of haptic perception. My work on haptic interfaces takes the latter approach. Current projects investigate how to provide interaction with refreshable tactile graphics.

Visual Impairment

Tactile Graphics & Braille

Multiple projects investigate haptic perception and finger movements associated with braille and tactile-graphic materials. Some of these also investigate how these materials can be designed and supported to produce best performance and achievement for people and students who have visual impairments.

Psychoeducational Assessment & Mathematics Achievement

A set of accessible measures does not exist to provide a comprehensive psychoeducational assessment of students who have visual impairments. In a collaboration with Dr. Amanda McKerracher, there are projects investigating how to create such measures, spurred originally by our interest in relating cognitive abilities to mathematics achievement in student who have visual impairments. Students with visual impairments lag behind their sighted peers especially in mathematics. One possible explanation is that without the visualization abilities that accompany vision, students who are blind struggle to represent traditionally visual mathematical concepts. Our results suggest that this is not the primary cause of mathematics difficulties, which instead stem from a lack of exposure to mathematical concepts and poorly adapted learning materials.

TVIs' Adoption of Assistive Technology

Specialized assistive technology (AT) allows students with visual impairments access otherwise inaccessible academic materials. For example, a student may use a CCTV to enlarge text or a refreshable braille display to access text. Teachers of students with visual impairments (TVIs) are responsible for obtaining AT and teaching their students how to use it, but acceptance of AT among TVIs is surprisingly low. Despite pre-service training, which is necessary to introduce TVIs to existing AT, a TVI may need to interact with a community that supports and promotes AT to continue learning and using unfamiliar AT. This research is in collaboration with Dr. Ting Siu.