Amir Levine

And that’s how this book came to be

In this particular study, which he conducted in collaboration with Richard Davidson and Hillary Schaefer, he used functional MRI technology to scan the brains of married women. While these women were being scanned, Dr. Coan and his colleagues simulated a stressful situation by telling them that they were about to receive a very mild electric shock.
Normally, under stressful conditions the hypothalamus becomes activated. And indeed this is what happened in the experiment to the women when they were alone awaiting the shock—their hypothalamus lit up. Next, they tested the women who were holding a stranger’s hand while they waited. This time the scans showed somewhat reduced activity in the hypothalamus. And when the hand that the women held was their husband’s? The dip was much more dramatic—their stress was barely detectable. Furthermore, the women who benefited most from spousal hand-holding were those who reported the highest marital satisfaction—but we’ll get back to this point later.
The study demonstrates that when two people form an intimate relationship, they regulate each other’s psychological and emotional well-being. Their physical proximity and availability influence the stress response. How can we be expected to maintain a high level of differentiation between ourselves and our partners if our basic biology is influenced by them to such an extent

What proved through evolution to have a strong survival advantage is a human couple becoming one physiological unit, which means that if she’s reacting, then I’m reacting, or if he’s upset, that also makes me unsettled. He or she is part of me, and I will do anything to save him or her; having such a vested interest in the well-being of another person translates into a very important survival advantage for both parties