“I mean, it’s ridiculous,” Dhuey says. “It’s outlandish that our arbitrary choice of cutoff dates is causing these long-lasting effects, and no one seems to care about them.”

“Mimicry, they argue, is also one of the means by which we infect each other with our emotions. In other words, if I smile and you see me and smile in response—even a microsmile that takes no more than several milliseconds—it’s not just you imitating or empathizing with me. It may also be a way that I can pass on my happiness to you.”

“To build a better world we need to replace the patchwork of lucky breaks and arbitrary advantages today that determine success--the fortunate birth dates and the happy accidents of history--with a society that provides opportunities for all.”

“Living a long life, the conventional wisdom at the time said, depended to a great extent on who we were—that is, our genes. It depended on the decisions we made—on what we chose to eat, and how much we chose to exercise, and how effectively we were treated by the medical system. No one was used to thinking about health in terms of community.”

“People are in one of two states in a relationship,” Gottman went on. “The first is what I call positive sentiment override, where positive emotion overrides irritability. It’s like a buffer. Their spouse will do something bad, and they’ll say, ‘Oh, he’s just in a crummy mood.’ Or they can be in negative sentiment override, so that even a relatively neutral thing that a partner says gets perceived as negative.”

“It is those who are successful, in other words, who are most likely to be given the kinds of special opportunities that lead to further success. It’s the rich who get the biggest tax breaks. It’s the best students who get the best teaching and most attention. And it’s the biggest nine- and ten-year-olds who get the most coaching and practice. Success is the result of what sociologists like to call “accumulative advantage.”

“What does it say about a society that it devotes more care and patience to the selection of those who handle its money than of those who handle its children?”