For his whole life, Kirby Deater-Deckard has been an avid people watcher. Thus, he said, it was no surprise to his friends and family that he chose to study psychology.

“I’ve always been fascinated by the variety of people you see no matter where you are in the world,” said Deater-Deckard, professor in the Department of Psychological and Brain Sciences (PBS) at UMass Amherst.

His interest in the field was first piqued when he took a psychology elective at his Baltimore-area high school, and was cemented by an undergraduate introduction to psychology course at Pennsylvania State University taught by Julian Thayer. Deater-Deckard had originally planned to study biology, but Thayer’s course—along with a course on individual and family studies taught by Susan McHale—opened his eyes to the idea of investigating complex human behavior and social relationships using scientifically rigorous methods. He went on to earn a BA in psychology and human development from Penn State and an MA and PhD in psychology from the University of Virginia, and completed postdoctoral training at Vanderbilt University and King’s College London. He was on the faculty at the University of Oregon and Virginia Tech, among other positions, before joining the UMass Amherst faculty in 2016.

Early in his academic career, Deater-Deckard became focused on studying individual variations in self-regulation. He defines self-regulation as one’s capacity to respond to new information in the environment in goal-directed ways and to control those responses in manners that minimize wear and tear on the body while maximizing opportunities for learning and growth. A child’s self-regulation can be seen in how easily they can be soothed—or can self-soothe—when upset, or how likely they are to become upset in the first place under stress. Self-regulation is a key aspect of individual development, with strong connections to behavioral, emotional, and cognitive functioning, as well as health outcomes from childhood through old age.

In his Individual Differences in Development Lab (IDDLab) at UMass—with locations on the Amherst campus and in the UMass Center at Springfield—Deater-Deckard conducts large-scale studies of individual differences in self-regulation, both in the U.S. and abroad. His research examines genetic, neurological, and physiological factors related to self-regulation, and how they interact with environments in families, neighborhoods, and schools. Participants range from early childhood through adulthood.

For example, with funding from the National Science Foundation (NSF), he is collaborating with PBS colleague Adam Grabell on a study using functional near-infrared spectroscopy (fNIRS) brain imaging and measures of cardiac physiological activity to examine development and self-regulation in preschoolers.

In another study, funded by the National Institutes of Health’s (NIH) National Institute on Drug Abuse (NIDA), Deater-Deckard and Virginia Tech collaborators seek to understand how individual differences and developmental changes in adolescents’ self-regulation promote shifts in decision-making for behaviors such as substance abuse, risky driving, and risky sexual behavior.

For the past 15 years, Deater-Deckard has also collaborated on a nine-country, five-continent longitudinal study based at Duke University, known as Parents and Adolescents Across Cultures (PAC). Beginning when the children in the study were 8 years old, it uses survey data and direct behavioral assessments to examine measures of self-regulation, executive functioning, distractibility, and impulsivity.

“Even in these very different cultures and contexts, what has struck me is that the individual differences patterns are very consistent,” said Deater-Deckard. “There are powerful site-specific cultural differences, but the factors we’ve measured don’t appear to predict much of the individual variation between youth that we’re seeing within each location.”

The study recently received another five years of funding from the NIH's National Institute of Child Health and Human Development. The researchers plan to continue following the cohort as they enter early adulthood and become parents themselves.

Deater-Deckard will apply lessons learned about doing cross-cultural research in a new project, the FinnBrain Birth Cohort Study in Finland. A center of excellence grant from the Academy of Finland will fund a broad series of studies on topics including developmental disabilities and mental and behavioral disorders. In collaboration with his Finnish colleagues, Deater-Deckard will aim to develop spin-off projects in the U.S., integrating brain imaging, physiological measures, and genomics, as well as behavior.

In addition to his research, Deater-Deckard is co-author of two widely used college textbooks on child and adolescent development published by McGraw Hill: Child Development: An Introduction, now in its 16th edition, and Children, in its 15th edition. He is also credited with developing and disseminating the Parent-Child Interaction System (PARCHISY), a free assessment tool used in clinical settings and by many research teams throughout the Americas, Europe, and Australia.

Deater-Deckard's research also informs public discussions and policies vis-a-vis parenting stress and resilience. He has consulted with groups ranging from the Sesame Workshop, to UNICEF, to the Child Health Investment Partnership (CHIP) of Roanoke Valley (Virginia) on messaging campaigns and health care programs related to creating healthy, happy environments for children’s development. And for the broader public, Deater-Deckard wants to normalize the stress associated with parenting, and the need for social and community support of parents and caregivers.

“Many cultures and media often portray parenting as purely joyful, and emphasize independence in caregiving,” he said. “Yet research shows that parenting is stressful, and caregiving done in isolation isn’t healthy for anyone. Parents need family, friends, neighbors and community members to offer support.”

Just as schools have shifted towards individualized instruction to meet the needs of each student and healthcare towards personalized medicine, Deater-Deckard's research on individual variation in development suggests a more individualized approach is needed for parenting and caregiving.

“Each child is so different,” he said. “The role of parents and caregivers is to provide a foundation of love, security, and knowledge, but also to reinforce the uniquely individual strengths of each child.”