What Anyone Who Wants to Love Should Know
One day, a peculiar advertisement appeared on bulletin boards around the Yale University campus: "Recruiting couples who started dating less than three months ago. Compensation provided." Sixty couples answered the call, along with forty-three singles of similar age who joined as a comparison group. The research team separated each couple and conducted thirty-minute interviews about their romantic relationship. Then they measured blood oxytocin levels in everyone — singles and newly coupled alike.
The results were striking. The couples' oxytocin was a full two times higher than the singles'. And among the couples, those who reported stronger emotional connection had the highest levels of all. As I mentioned earlier, this study demonstrated something remarkable: a couple's oxytocin levels could predict whether they would still be together six months later.1
Another elegant study on the chemistry of romance came from the psychology department at the University of North Carolina. Researchers assembled 129 couples — 258 individuals — all of whom had been together for at least a year. One partner from each couple was randomly selected to record a short video message expressing gratitude, which was then shown to the other. These were not tossed-off recordings. Each person was asked to identify something specific their partner had recently done that they were grateful for, and to describe how it made them feel. The emotional dimensions measured were precise: awareness of the partner's reaction, the experience of love, the sense of reward, depth of gratitude, perception of the partner's own gratitude, perception of the partner's love, and the partner's sense of being valued. As the researchers expected, couples with higher oxytocin scored higher on every single dimension — more gratitude, more love, more positive emotion when appreciation was expressed.2
It stands to reason that couples running on high oxytocin are more likely to last. When oxytocin is elevated, partners look into each other's eyes during conversation. They pick up on each other's nonverbal cues with ease. They feel grateful for small things and pay attention to tiny details. All of this feeds the relationship, making it healthier and more durable. And the arrow points both ways: physical affection, sex, sharing meals, and heartfelt conversation all raise oxytocin in return. Couples who are doing well send their oxytocin climbing even higher — a virtuous cycle, gathering momentum with every turn. To every couple reading this book: if you want to keep what you have, look at each other more often. Hold hands more. Embrace more. Share meals together. Show more care in the small things.3