Illinois Twin Project

The Illinois Twin Project will help us understand how genetic and environmental factors combine to influence child development.


The Illinois Twin Project will create a database of parents of twins (both identical and fraternal) or other multiplies in Illinois who might be willing to have their children participate in future research studies. Studying twins allows us to better learn about the causes of children’s life outcomes by unraveling the interconnected influences of genes and environments.

Get Involved



We are currently recruiting participants for the Illinois Twin Project. Families with multiples ages 17 and under can participate by completing an online survey with the opportunity to participate in future lab research at Northwestern University or the University of Illinois at Urbana-Champaign.


About the Project Co-Directors



Daniel Briley

Daniel Briley

Daniel is an assistant professor of psychology at the University of Illinois at Urbana-Champaign. His research examines how individual differences in personality influence the ways in which people approach and interact with concepts and ideas. He is particularly interested in developmental issues that arise as children transition through the educational system and gain knowledge and beliefs about how the world works.


Jennifer Tackett

Jennifer Tackett

Jennifer is an associate professor of psychology and the director of clinical psychology at Northwestern University. She is the director of the Personality Across Development Lab at Northwestern, where her research focuses on the development of personality in children and adolescents as well as how personality traits relate to behavior and affect relationships with friends and parents.


Relevant Publications