Our modern idea of happiness—that it’s something everyone can earn and that we all deserve—would have been completely unfamiliar to our ancestors. Darrin McMahon, author of Happiness, A History, points out that the word “hap” is Old Norse and Old English for “luck” or “chance.” Happiness, he says,  “was in the hands of fate or fortune. It was literally what happened to you.”

Happiness before the 17th century

While the Greek and Roman philosophers believed you could achieve happiness by living a good, virtuous life, that life might include plenty of pain (sometimes literally). “Cicero claimed the happy man will be happy even on the torture rack,” says McMahon. Happiness, as far as the ancients were concerned, was such hard work few could hope to realize such a state. In the Christian tradition, happiness wasn’t something you could expect during your time on earth. You achieved it in the next life, providing you lived piously and virtuously during this one. In short, you had to be dead to enjoy it.

It wasn’t until the Age of Enlightenment in the 17th and 18th centuries that the idea arose that happiness should be for everyone. Americans may be happier today than our 19th century predecessors—no child labor and the invention of antibiotics being just a couple of reasons—but there’s no real way to tell because social scientists didn’t start to measure happiness until the 1940s.

Are we happier now?

You might think the upheavals of the 20th century would have had an effect on people’s happiness: The first World War, the roaring twenties, the Depression, World War II, not to mention social change after the war when many women left their jobs and returned to the hearth, while men conquered the workforce and the economy boomed. Then there was the upheaval of the 1960s—the civil rights movement, changing social mores, the Vietnam war, followed by an economic downturn and more political and social upheaval in the 1970s. Feminism came about because many women weren’t happy with the status quo. But none of this shows up in any spikes or dips on the happiness graphs.

“What makes most people happy or unhappy has to do with their personal or family lives—are they getting along with their kids, their spouse, the neighbors?”

Tom Smith, principal investigator for the General Social Survey at NORC at the University of Chicago

Since the late 1940s, when happiness surveys began, happiness has remained pretty stable. Americans don’t appear to have become much happier—or unhappier—in the decades since. Tom Smith, principal investigator for the General Social Survey at NORC at the University of Chicago, says there are a couple of good reasons for this: “What makes most people happy or unhappy has to do with their personal or family lives—are they getting along with their kids, their spouse, the neighbors?—and not whether some international incident is brewing or whether there’s a new controversy about gay marriage.”

Smith says those larger things, though they may have a great impact on society as a whole, simply don’t drive happiness. Also, he says, in boom times people may do well, but they re-evaluate their situations during those heady days and tell themselves while they may be thriving, so is everyone else. They adapt to the times. This is what psychologists call “the hedonic treadmill.” The same goes for bad times, when people don’t tend to report being less happy than usual because, again, they adapt to the general temperature of the era.

That said, the current economic downturn has caused a dip in happiness. The General Social Survey of 2010 shows general happiness fell to an all-time low, with 29 percent of respondents describing themselves as “very happy.” That’s a drop of 5 percent since 2004. The percentage of people describing themselves as “not too happy” rose. Michael Frisch of Baylor University adds another depressing note: “In times like this, all the mental illness indices are off the graph: child abuse, wife abuse, alcohol and drug abuse, depression and anxiety.”