Lab Researchers

Principal Investigator

Percival Matthews smiling in a black blazer with purple and white plaid button-up shirt.

Percival Matthews
Principal Investigator
Curriculum Vitae

My research program is organized around two primary goals: 1) to understand some basic underpinnings of human mathematical cognition, and 2) to find ways to leverage this understanding into effective educational techniques that can be used to impact the life chances of everyday people. My research has spanned all stages of development and has included work both in K-12 schools and in the laboratory. Currently, my largest projects involve

  • exploring how basic perceptual abilities that all humans come with can help anchor understanding of fractions concepts and
  • investing how we can improve children’s understanding of the equal sign, a type of knowledge that is an important entry point for algebraic thinking.

When I’m not in research mode, I enjoy hanging out with my wife and two daughters, experiencing new foods, working out, and reveling in the music of the ’70s (which I feel set the high water mark for popular music).

Postdoctoral Researchers

Sangmi Park
Postdoctoral Researcher

Sangmi is a postdoctoral researcher at UW-Madison. She earned her B.A. in Psychology and M.A. in Child Psychology and Education from Sungkyunkwan University in South Korea, and she earned a Ph.D. in Psychology at Clark University. Her broad research interests include children’s learning in mathematics. Her most recent research explores how children understand rational numbers and how this relates to their mathematics achievement. Her research interest also includes identifying linguistic and cultural factors that impacts children’s math comprehension. Her work aims to provide insights that can help improve children’s math performance.

Graduate Students

Robby Quintana posed in blue button-up with wool jacket.Robert Quintana
Graduate Student

Robert graduated from Gustavus Adolphus College where he earned a B.A. in Psychology. After graduation, Robert worked at an alternative school, where he served as a teaching assistant in a classroom for children with emotional/behavior difficulties. He also worked a Behavioral Technician at Wisconsin’s Early Autism Program and as a math tutor for Schools of Hope in the MMSD school district.

Research Interests: Robby is interested in how the development of certain cognitive abilities influence mathematical understanding and trajectories. Specifically, how differences in spatial skill and proportional reasoning influence fraction understanding and general calculation skill. He hopes this research will contribute towards new learning tools and interventions to that make math more accessible and fun . In his downtime, he likes to take long walks in areas with vegetation and water, bike around Madison, and work on his jump shot.

Lab Manager

Valerie Buroker
Lab Manager

Valerie is the MELD Lab manager and the project manager for the Fractions & Algebra Project, which investigates the relations between fractions and algebra in middle and high school students. She graduated from UW-Madison in 2022, where she earned a B.S. in Psychology and Neurobiology. As a previous undergraduate research assistant in the MELD lab, she was excited for the opportunity to return to research after working as a special education paraeducator for a year.

In her free time, Valerie enjoys traveling, painting, reading, being outdoors, and spending time with friends and family.

Undergraduate Research Assistants

Xiang Cheng
Undergraduate Research Assistant
Xiang is a senior from Guangzhou, China. This is her third year working in the MELD Lab. She is majoring in Education Studies and Mathematics, working on Statistics and Arts & Teaching certificates. In the past, Xiang has been tutoring high school students in mathematics. After graduation, she hopes to pursue a Doctoral Degree in Educational Psychology and work as a researcher. She enjoys writing calligraphy, playing Pipa, singing, and watching cute animal videos in her free time.

Maddie Pritz
Undergraduate Research Assistant
Maddie is a first-year undergraduate student at UW-Madison from Grayslake, IL. She is majoring in Psychology, and this is her first year working in the MELD lab. After finishing her undergraduate degree, she aspires to go to graduate school on the Cognitive Psychology track. Outside of school and the lab, she finds joy in playing the guitar, creating art, and eating good food.

Daria Zikel
Undergraduate Research Assistant
Daria is a senior at UW-Madison from Kenosha, Wisconsin. This is her second year working in the MELD Lab. She is majoring in Psychology and Neurobiology. She hopes to pursue a career in healthcare after undergrad and graduate education. Outside of school and the lab, Daria enjoys reading, playing piano and hanging out with her friends.

Madilyn Kaiser
Undergraduate Research Assistant
Madilyn is a junior at UW-Madison from Pulaski, Wisconsin. This is her first semester working in the MELD Lab. She is majoring in Psychology, and hopes to go to graduate school to become a Physician’s Assistant. Outside of school, work, and the lab, Madilyn enjoys traveling, movies, and spending time with friends and family.

Amelia smiling in black turtle-neck with gold necklaces.Amelia Jensen
Undergraduate Research Assistant
Amelia is a fourth-year undergraduate student at UW-Madison originally from Crystal Lake, Illinois. This is her seventh semester in the MELD Lab. She is majoring in Biochemistry with certificates in Gender & Women’s Studies and Biocore Curriculum. She hopes to go to graduate school to pursue her DNP and become a Women’s Health Nurse Practitioner. Besides school and work, with her time, Amelia enjoys sleeping, cooking, and spending quality time with those she loves most.

Devon Adams
Undergraduate Research Assistant
Devon is a first-year undergraduate majoring in neurobiology on a pre-physician assistant track and working towards a certificate in either global health or gender and women’s studies. Her hometown is Onalaska, WI and some of her hobbies include reading, baking, and spending time with friends and family.

Graduate Alumni

Yunji Park
Curriculum Vitae

Yunji is a postdoctoral scholar in the department of psychiatry at Stanford University. Yunji completed her Doctorate and a Masters in Educational Psychology at the University of Wisconsin-Madison, and she earned her bachelors degree and a Masters in Cognitive Science in South Korea. Working in the Cognitive Neuroscience Lab, she was involved in the various projects studying the development of numerical cognition. Yunji specifically investigated the representation of magnitude and how it relates to mathematical achievement over the course of the development.

Research Interests: I’m interested in young learners and their brain development in the context of math education. I’m also interested in kids’ structural and functional brain changes shaped by educational experience! My current project focuses on the development of nonsymbolic ratio discrimination and its relationship with math competence (behavioral), children’s neural representations for nonsymbolic and symbolic fractions and how the representation changes over the course of development using fMRI, and exploring white matter tracts that are related with fractional knowledge using DTI. If you are interested in my work and want to know more, please visit my personal web page.

Alex Viegut smiling in red cardigan with black and white shirt underneath.

Alexandria Viegut
Curriculum Vitae

Alex is an assistant professor in the psychology department at UW – Eau Claire. Her current research focus is measuring and supporting students’ understanding of fractions, especially through visual models. She earned Ph.D. (2022) and M.S. (2019) degrees in Educational Psychology at UW-Madison, and holds a B.A. in Psychology from the University of Notre Dame. After completing her PhD, she worked as a postdoctoral researcher in Learning Sciences at the University of Delaware. As a graduate student, Alex enjoyed teaching undergraduate child and adolescent development classes in the Educational Psychology Department.

Research Interests: My work draws from both psychology and math education research, and I’m currently exploring connections between fractions and algebraic thinking. I am also interested in the role of visual representations (number lines, gestures, diagrams, etc.) in children’s math thinking and learning. If you’d like to hear more about my research, please visit my professional website or email me at! Outside of research and teaching, I enjoy running, card games with friends, and playing piano.

Lab Alumni

Catherine Abitz

Lydia Ahn

Jodi Allison

Joe Anistranski 

Grace Backes

Madison Berg

Aila Bretl

Robyn Breunig 

Brian Brito

Olivia Burdick

Valerie Buroker

Sarah Cable

Ashley Carfagno

Joao Catao

Yuxin Chen

Sophie Diers

Rose Eisenmenger

Kristina Fassbender

Catherine Finedore

Gianna Frale

Maggie Gannon

Mary Gannon

Anna Grassman

Dana Grindall

Josie Hintzke

Emily Holt

Amelia Jensen

Gemma Kirk

Matt Konz

Carol Koshick 

Kimberly Lense

Alex Lindstrom 

Xiaoru Ma 

Bridget Manion

Rui Meng

Phoebe Miller

Erin Nguyen

Mikayla Oertel 

Soren Paape

Italo Paz-Cuervo

Nya Pottinger

Jessica Poh

Cady Roedl

Ally Romanov

Raeleah Schaeffer 

Stewart Schultze

Lucy Shoemaker

Paige Sideris

Jessica Sullivan  

Julia Szynal

Persephone Valentine

Alex Wehrle    

Claire Westenberger 

John William Washa

Caro Williams

Sara Wright

Sai Xiong

Yining Zhang

Daria Zikel

Ryan Ziols