Rachel Ka-Ying Tsui, PhD

Quantitative Behavioral Research Scientist

Tokyo, Japan

Hi there!

As a quantitative behavioral research scientist,

I study how humans perceive, navigate, and interact with the world around them.

With 10+ years of experience in human behavior research, I specialize in using quantitative methods and multidisciplinary approaches to understand and solve questions about how people think, perceive and interact with the world around them.

My work draws on a wide range of methodologies, including A/B testing, eye-tracking, moderated / unmoderated usability testing, as well as surveys and interviews. One thing I particularly enjoy doing is analyzing and visualizing quantitative data to uncover meaningful patterns in what people pay attention to and how they process information around them.

I've worked with diverse populations in Japan, Canada, and Hong Kong, and have collaborated internationally with teams in the US, France, Korea, and Singapore. These experiences have given me a global and inclusive perspective on human behavior. Also, I am multilingual: fluent in Cantonese (native), English (bilingual), Japanese (professional), and Mandarin (professional).

I'm excited to bring my research skills into the world of UX, where I can continue asking human-centered questions and help create intuitive, evidence-based experiences.

Please feel free to reach out with any questions about my work!

Warmly,
Rachel

Skills & Competencies

Research Methods

A/B testing
Benchmarking
Competitive analysis
Eye-tracking
Interviews & Surveys
Moderated & unmoderated usability testing

Statistics

Descriptive & inferential statistics
Linear & logistic mixed modeling
Simple and Multiple Regression
ANOVAs
T-tests

Programming & Software

R, R markdown
SPSS
SQL
Git
Figma

Education

PhD in Developmental Psychology,
The University of Hong Kong 2019
MA in Linguistics,
The University of Hong Kong 2014
BA in Linguistics & Japanese,
University of California, Berkeley 2013

Languages

Cantonese (native)
English (bilingual)
Japanese (professional)
Mandarin Chinese (professional)

Professional skillset

Data analysis & visualization
Human behavior research
Project management
International collaboration
Public speaking
Science communication

Experience

Research Experience

I have a Ph.D. in Developmental Psychology, with domain expertise in human factors / human behavior, language learning, and cognition. My research journey began with a focus on how human babies acquire language — specifically, how their environment shapes what and how they learn. I’ve always been fascinated by how even the smallest cues in a baby’s surroundings can influence their ability to absorb and process language. My work has explored these early learning processes across cultures — including in Hong Kong, Canada, and Japan, contributing to our understanding of bilingual development and early language education. I had extensive training on quantitative methods, and am driven by a deep curiosity about how people make sense of and engage with the world around them.