Who are we?

Principal Investigator: Matthew Zawadzki


Dr. Matthew Zawadzki is an Assistant Professor at the University of California, Merced. He received his undergraduate degree in Psychology and Philosophy from Iona College (New Rochelle, NY), his Masters degree in Quantitative Methods from Columbia University (New York, NY), and his PhD in Social Psychology and Women’s Studies from The Pennsylvania State University (University Park, PA). His research examines what stress is, why it is bad for you, and what we can do about it. Although we all experience stress in our lives, what we mean by stress can range from bad things happening in the world to negative thoughts we carry in our minds. His lab looks to develop ways to measure these components of stress and to test whether they differentially predict one’s health. The lab is also interested in ways we can reduce stress in our lives and improve health and well-being. He grew up in New York City, and has some pretty strong opinions on pizza, including how it should be eaten, the proper crust thickness, and cheese to sauce ratio.



Current Trainees


Amanda Small

Amanda Small is a PhD candidate in health psychology. With a background in public health and substance use prevention, her research focuses on the socio-environmental determinates of stress, coping, and health. Amanda's work looks at how the exposures and experiences in everyday life are influenced by the contexts and environments where they are occurring and how those influences can lead to changes in health and well-being. Outside of her studies, Amanda loves music and dancing; she currently plays 4 instruments herself and has pursued dance and movement in many different genres all her life. 



Larisa Gavrilova

Larisa received her undergraduate degree in Psychology from CSU Northridge (Cum Laude); she is currently a Ph.D. Candidate in Psychological Sciences at UC Merced. The overall goal of her work is to inform the development of effective interventions aimed at improving health and promoting healthy lifestyle. To achieve this goal, her first line of research investigates the mechanisms through which psychosocial factors (stress, coping styles, emotions) affect health, specifically when it comes to cardiovascular disease risk factors (e.g., elevated blood pressure, physical inactivity, inadequate sleep, psychological distress) in everyday life. Ultimately, with her work she wants to inform effective interventions that are easily accessible to underprivileged populations and help reduce health disparities. In her free time, she likes to go to the beach with her dogs and do yoga.




Amber Arroyo Photo

Amber Arroyo

Amber Carmen Arroyo graduated cum laude in May 2015 from California State University, Chico. She worked in the PsychoNeuroEndocrinology Lab at UC Merced from August 2016-December 2018, and then joined the Stress & Health lab in January 2019. Her work combines evidence-based methods of behavior change with technology to promote health and wellbeing among high-risk and hard to reach groups. She enjoys working with diverse forms of data (i.e., biomarkers, surveys, EMA, Fitbit, anthropometric) to gain a comprehensive understanding of wellbeing and how it is formed through the dynamic balance of biological, psychological and social health. In her copious amounts of free time, she enjoys hiking, running, and spending quality time with family and friends. She maintains her sanity by working with the puppies in training at Guide Dogs for the Blind.


Armin HojjatyArmin Hojjaty

Armin Hojjaty is currently a PhD student in the Health Psychology program at the University of California, Merced. He earned a B.S. in psychology and a B.S. in biology from the University of Georgia before earning his M.S. in Health Solutions from Arizona State University. Armin's research interests focus on decision-making, perception, and stress as they related to health. Additionally, he is interested in how time, environment, genetics, and culture are linked to cognitions that influence health outcomes. In his free time, Armin loves boxing, playing basketball, and spending time outdoors with his dog, Otto.





Undergraduate Researchers 

Spring 2021

Amanda Small, Hannah Dillon, Matthew Zawadzki, Stephanie Reyes, Tammy Yung, Armin Hojjaty, Larisa Gavrilova, Bryant Williams, Stephanie Soto Rodriguez, Maya Changaran Kumarath, Amber Arroyo, Jessica Chapman, Destiny Macedo, Mariah Richardson, John Vang

Fall 2020

Lab Photo Fall 2020

From top left to bottom right: Larisa Gavrilova, Mariah Richardson, Armin Hojjaty, Stephanie Reyes, Amber Arroyo, Hannah Dillon, Matthew Zawadzki, Jason Lee, Izza Belle Ygnalaga, Giovanni Alvarado, Stephanie Soto Rodriguez, Jessica Chapman, Amanda Small, Maya Changaran Kumarath, Sierra Henderson, John Vang, Destiny Macedo, Yesenia Ramirez Sigala, Tammy Yung, Tamy Do. 


Spring 2020

From top left to bottom right: Stephanie Reyes, Amanda Small, Maryam Hussain, Matthew Zawadzki, Tamy Do, MaKaela Burt, Jessica Chapman, Esther Lapite, Maria Talamantes, Trixy Ibis, Samaria Berry, Maya Kumarath, Larisa Gavrilova, Hannah Dillon, Amber Arroyo, Sierra Henderson, Jason Lee, Adrienne Baggie, Destiny Macedo, Giovanni Alvarado.


Fall 2019

Giovanni Alvarado, Trixy Angelie, Amber Arroyo, Valeria Cervantes, Jessica Chapman, Pedro Garcia, Larisa Gavrilova, Sierra Henderson,  Maryam Hussain, Esther Lapite, Destiny Macedo, Stephanie Reyes, Mandy Small, Maria Talamantes, Matthew Zawadzki.


Spring 2019


From left to right: Valeria Cervantes, Mariamawit (Mawit) Belette, Jessica Gonzalez, Giovanni Alvarado, Marina Bojorquez, Maria Talamantes, Zhane' Mejino, Dannavie Faye Abenojar, Gabriela Diaz, Rachel Needham, Matthew Zawadzki, Lydia Kim, Pedro Garcia, Larisa Gavrilova, Sydney Herring-Alderete, Xochilt Alcala Quinonez, Gino Acevedo, Amanda Small, Shun Ting (Tammy) Yung, Maryam Hussain, Amber Arroyo, Hanul (Sky) Lim,  Charles Udeze (not pictured: Deanna Halliday, Carmen Kho).

Fall 2018



From left to right: Kareena Karki, Gabriela Diaz, Maria Talamantes, Sylvia Sanchez, Dannavie Faye Abenojar, Larisa Gavrilova, Valeria Cervantes, Zhane' Mejino, Rachel Needham, Patricia Razo, Pedro Garcia, Xochilt Alcala Quinonez, Matthew Zawadzki, Deanna Halliday, Sydney Herring-Alderete, Gino Acevedo, Amanda Small (not pictured: Maryam Hussain).

Spring 2018



From left to right: Viviana Martinez, Paloma Cortez, Sydney Herring- Alderete, Sylvia Sanchez, Elizabeth Ochoa, Matthew Zawadzki, Theodore Baza, Larisa Gavrilova, Pedro Garcia, Amanda Small (not pictured: Deanna Halliday).

Fall 2017



From left to right: Elizabeth Ochoa, Larisa Gavrilova, Matthew Zawadzki, Deanna Halliday, Gino Acevedo, Amanda Small, Viviana Martinez, Sylvia Sanchez, Sydney Herring-Alderete.



Friends of the Lab


Deanna Halliday

Deanna studied judgement/decision-making research and social psychology at California State University, Fresno, where she received her BA and MA. As a graduate student at UC Merced, her research explores the cognitive influences on health decision-making, particularly the role of risk perceptions. With the Stress and Health Lab, she has used ecological momentary assessment to examine how context influences smoking beliefs and behaviors. She has also enjoyed a position as a graduate student researcher at the Nicotine and Cannabis Policy Center where she has helped to coordinate and facilitate data collection in numerous California counties. Deanna spends her free time watching scary movies and hanging out with her dog, Poppy (who also enjoys the movies, as long as there are no scary dogs).


Carmen Kho

Carmen Kho is an international student from Malaysia. She obtained her MA in Clinical Psychology from CSU Dominguez Hills. With the Stress and Health Lab she is working on examining how culture fluctuates and changes in everyday life, and how this may impact our social, affective, and physical health. She loves travelling, spicy food, and the color green.


Maria Ramirez Loyola

Maria Ramirez Loyola earned a B.A. in psychology at UC Riverside in 2016 and an MA from UC Merced in 2018 in the same subject. In the Stress and Health Lab she is examining how ethnic/racial identity may function as a source of resilience in the associations between perceived ethnic/racial discrimination and health in the daily life of Latino young adults. One fun fact about her is that she loves to read and happens to be a huge Harry Potter fan.





Shun Ting Tammy Yung

Tammy Yung received her B.A. from UC Berkeley and is now pursuing her PhD in Developmental Psychology at UC Merced. Her research interests are examining social and emotional development of children and adolescents across cultures with an emphasis on family socialization. With the Stress and Health Lab, she is examining loneliness and psychological distress with a real-time approach. 





Lab Alumni

Maryam Hussain

Dr. Maryam Hussain is a post-doctoral scholar in the Stress & Health Lab and Merced Experimental Social & Health Psychology (MESH) Lab. She earned her PhD from the University of Houston with a focus on Developmental & Learning Psychology and Statistics & Measurement. As part of her post-doctoral training with Dr. Zawadzki, she is examining changes in cardiometabolic functioning related to in-the-moment psychosocial stressors and positive social connections among Latino adults. With this training, Maryam hopes to do research as a health psychologist focused on the importance of sociocultural resiliency when considering morbidity. One fun fact about Maryam is that she was born in a small village in India, immigrated to the US at age 5, and is now a co-founder and stakeholder at a library and tutoring center in her birth village.





Jennifer Mendiola

Jennifer Mendiola was part of the Stress and Health Lab from 2015-2017 where she examined how social relationships and emotions had in-the-moment effects on health. She received her PhD posthumously in 2017.