Maybe you have a New Year’s resolution that’s still unbroken.

I’m guessing that whatever it is – to lose weight, to give to charity, to reconcile with a family member, to change careers – the motive is the same. You want to be happier.

I mean, duh. Why do anything unless it’s going to make you happier?

But here’s a question: What is happiness, anyway?

Duh? OK, but two new books offer provocative answers to what might seem too obvious to ask.

The first, “The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom,” by Jonathan Haidt, begins with the advice of Christianity, Buddhism and other religions and philosophies on what makes us happy. You know: Do unto others as you would have them do unto you, detach from material possessions, realize that happiness is a construct of your mind, etc.

Then Haidt, a psychologist who researches morality, compares the advice to what psychologists are finding experimentally. Much – but not all! – of the advice holds up.

The second, “Happiness: A History,” by historian Darrin M. McMahon, reminds us that what constitutes “happiness” changes with time. Humans did not always believe that happiness lies within our grasp. And humans did not always believe that the pursuit of happiness is our right. Take that, Thomas Jefferson.

I can’t resist books on the science of happiness, it seems. Last February I was enamored of “Happiness: Lessons From a New Science,” by Richard Layard, which introduced me to modern psychology’s research and to the Enlightenment’s view of happiness.

I still like the Layard, but today’s books fill in what he sped through, and that helps.

Start with Haidt’s “The Happiness Hypothesis.” Haidt is good with the memorable metaphor. One of his favorites is to describe the human mind as a rider on the back of an elephant. We’re divided, in other words, and in more than one way, between the instinctual and the rational, between what the body wants and what the mind wants, and so on.

Plato used a similar metaphor, of a charioteer holding the reins to two horses who want to go in different directions. So Plato was right, Haidt says, and the division comes up in research that shows, for instance, that we react more strongly to bad experiences than to good ones – even when we scold ourselves to look on the bright side. The rider can’t always steer the elephant.

Also, our baser elephant self is geared to care about prestige, not happiness, Haidt notes. We’re hard-wired to compare ourselves to others and to lust after what we think will give us greater status.

That explains InStyle magazine and its fawning over celebrities’ possessions. But status has very little correlation to lasting happiness, according to the research Haidt cites. Good for me, since I couldn’t afford Lindsay Lohan’s handbag, anyway.

What about other, oft-repeated wisdom? Adversity does make us stronger and, eventually, happier. That’s a consolation. But the Buddhist and Stoic doctrine of non attachment isn’t quite borne out by the research. Turns out we’re happier engaged in life than not. Whew, I say. I make a bad monk.

Once you’ve digested Haidt, move on to McMahon if you want to know more about how the ancients viewed happiness. Reading history has never made me that happy – too many boring early experiences – but McMahon provides readable proof that being happy wasn’t always the main goal in life.

Being courageous or virtuous has, at times, been more important to humans than being “happy.” Imagine. (Haidt finds that virtue – developing your character – goes a long way to ensuring your happiness, though.)

Together, the books might have you thinking that you made the wrong New Year’s resolutions after all. Which should make it less painful if you’ve broken them.

Aren’t you happier already?