British pediatrician D. Winnicott used to say:

“There is no such thing as a baby. There is a baby and someone.”

The same applies to brains. Our brains do not operate independently of relationships, which are conditioned by the environment in which we live.

Dr Daniel Siegel and Dr Allan Shore have for decades contributed to medical research that demonstrates how biography affects biology and thus shapes behavior. They call this topic Interpersonal Neurobiology. Dr Robert Sapolsky’s masterpiece Behave contributes to the field with a “quirky, opinionated and magisterial synthesis of psychology and neurobiology that integrates this complex subject more accessibly and completely than ever” (NYT review.)

In other words, picture your brain like a burger.

  • The bun is what we see from the outside: our body and our behavior
  • The meat is the organ itself, the most complex thing in the known universe
  • Tomatoes are our most important relationships. They don’t just regulate our brain with every interaction, they contribute to building the brain – especially attachment relationships from birth through early childhood.
  • The lettuce is the environment in which we live: the norms, beliefs and attitudes that surround us, but also the economic and social realities. The lettuce impacts the brain, both directly – the stress caused by hunger or violence – and indirectly via the relationships it affects – material needs may cause a parent to take on extra work, resulting in less energy and time to devote to a growing child’s brain.


In a nutshell, our environment shapes the caregiving relationships that shape the brain that shapes our life.