What Makes a Relationship: Building the Taxonomy of Early Relational Health

How scientists at the Center for Early Relational Health are building a universal framework for naming, understanding, and harnessing the many components of early childhood relationships

October 31, 2025

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Scientific breakthroughs are powerful, but they don’t change outcomes until they’re actionable. That’s why the Center for Early Relational Health brings together over 200 multidisciplinary doctors and scientists to lead the field’s first comprehensive research on every aspect of early childhood relationships—and, crucially, to put that science directly into the hands of pediatricians and the families they care for. 

Five years into our groundbreaking COMBO initiative, we’re excited to preview our preliminary findings on what makes a healthy relationship, what this means for families, and what’s on the horizon to turn evidence into action.

How Do We Quantify a Relationship?

There are lots of words people use interchangeably to talk about different parts of Early Relational Health, like bonding, attachment, and connection. But these terms actually apply to separate constructs, each describing one unique aspect of a relationship:

  • Bonding exclusively describes a parent’s feelings toward their child
  • Attachment exclusively describes a child’s behavioral response to a caregiver (during a stressful situation)
  • Emotional connection is a two-way construct to describe an emergent property of the interaction between a parent/caregiver and child. 

While there is broad evidence that these constructs are associated with overall developmental benefits, the field lacks the specific evidence needed to concretely say which relational levers families can pull to promote specific outcomes. That’s because these Early Relational Health constructs have never been studied together in a unified, longitudinal cohort of parents/caregivers and children—until now.

At the Center for Early Relational Health, we’re studying all of these pieces of the puzzle (and more) to understand how each one influences development and lifelong health.

The Building Blocks of How We Thrive

Like food, water, and sleep—social connection is actually a biological need. And this is even more important in childhood, when relationships can shape the course of our entire lives. 

Yet while we’re confident that positive interactions between young children and their families impact lifelong physical & emotional health, science can’t yet explain exactly how this happens. And that means we can’t yet harness these crucial interactions in universal pediatric care, to promote specific outcomes for families.

This is the central mystery in the science of Early Relational Health: the mechanisms of how connections form between children and their parents/caregivers, and how those connections help children & families flourish. 

Science has faced—and solved—essential mysteries like this before: 

By the 1950s, scientists understood the basic principles of genetics: we get half our genes from one parent and half from the other. And this formula influences every aspect of our make-up. “Because we understood these basic principles, we thought we had genetics figured out,” says Dr. Dani Dumitriu, pediatrician, neuroscientist, and Director of the Center for Early Relational Health. “But it wasn’t until the discovery of the double helix—the famous twisting-ladder shape of our actual DNA—that we broke the science of genetics wide open.” Suddenly, we had unlocked the mechanisms of our DNA: the foundational processes of how our bodies write, change, and carry out the genetic codes that shape our entire lives. 

“It wasn’t just about understanding genetics,” Dani says, “probing these individual components of the double helix turned out to be the key to using them effectively in medicine, to improve outcomes and lifespans for generations to come.”

Like genetics in the ‘50s, we have to probe the many components of relationships to truly understand how early social interactions shape lifelong outcomes: what happens in our bodies during moments of connection with each other? Do different aspects of relationships influence distinct health and well-being outcomes? What kinds of interactions promote a child’s brain development or social skills, or a parent’s mental health? 

Researchers at the Center for Early Relational Health are at the forefront of this cutting-edge science, to answer essential questions about how relationships can help us thrive from the very beginning. 

Dani says a core component of this mission is building the taxonomy of early relational health: “By naming, describing, and categorizing all the many components of relationships (and the many ways in which we can look at and analyze them), we can build a universal framework for understanding and harnessing social interactions. That is the foundation for actually making this science useful to pediatricians and families.”

That’s why our world-leading COMBO Initiative is the first longitudinal cohort study to deliberately include as many Early Relational Health constructs as possible. 

COMBO has already learned some surprising things about the components of relationships. So far, our preliminary data shows that: 

  1. There seems to be absolutely no association between bonding, maternal sensitivity, or emotional connection (when measured at 4 months, in a cohort of ~400 mother-baby dyads). This remains an open question—and one that the Center’s scientists continue to actively investigate.
  2. When measured in infancy (4 months), these constructs are associated with specific & distinct aspects of development when that child is 2 years old. 

For example, lower bonding correlates with “externalizing” symptoms (such as tantrums, impulsivity, or aggressive behaviors). Meanwhile, higher emotional connection is associated with some cognitive development and fine motor skills (like picking up a Cheerio), as well as gross motor skills (like running & jumping), a child’s ability to use language to communicate, and a child’s ability to understand language that is spoken to them (such as from a parent or teacher).

“This kind of specific evidence is especially important for things like school readiness,” Dani says. “Understanding which aspects of relationships impact the developmental milestones we care so much about, will allow us to start creating evidence-based interventions and responsible recommendations for families.”

What Needs to Happen Next, to Meaningfully Support Early Relationships?

So far, our research points to a reassuring message for families everywhere: not all healthy relationships look the same! Clearly, we can’t define a “healthy” relationship by any one construct. There are lots of influences on (and within) a relationship. Some families may lean into certain aspects more than others for any number of reasons, including parenting goals, community context, and societal norms. 

There is so much more to learn, but the Center’s pioneering research is already making strides in teasing apart the many aspects of these vital relationships, building the taxonomy of ERH toward actionable solutions for families. 

What’s more, we’re working on generating new Early Relational Health constructs—for example, by integrating in-depth parent interviews with cutting-edge machine learning—to develop untapped ways of understanding relationships from all angles. Through our unique video visit model (which makes it easier for families to participate in research), the Center’s scientists gather raw video data they can use now and in the future, to both develop new constructs and further investigate existing ones, as this science continues to evolve. 

The field of Early Relational Health holds enormous potential to embed strengths-based practices into universal pediatric care. Like breaking the genetic code, understanding the building blocks of our earliest relationships is the key to unlocking a new era in science and medicine: in which pediatricians have the knowledge they need to actionably promote connected relationships and strong families that help every child thrive.

 

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