It is the new year. A time for growth. A time to explore new possibilities in life. A time to sidle up to the person hogging the treadmill you want at the gym and whisper, “This won’t make you any happier, you know.”

Yes, that’s trolling. But it’s evidence-based trolling! Whether your resolution is to lose weight, stop smoking, or finally catch that road runner, research suggests that whether you achieve the goal or not might not matter as much for our overall happiness as we like to think. “Changing circumstances won’t make you hugely happier,” said Sonja Lyubomirsky, professor of psychology at the University of California Riverside. In other words, the folks who are virtuous enough to keep their resolutions aren’t necessarily enjoying their lives more than the rest of us. And, if they are happier, it’s not because they kept their resolutions — it’s because they made the right resolutions in the right way.

This downer of a holiday tidbit is borne out by years of research documenting correlations between life events and how people self-report their own sense of well-being, Lyubomirsky told me. For instance, a longitudinal study in Germany has followed the same 3,600 people for nearly two decades, annually documenting both their personal perception of how happy they are and the ways their lives have changed. Life events like marriage (makes you happy!) or divorce (makes you sad!) can temporarily affect people’s feeling of well-being, she said. But the studies show the effect wears off. After a couple of years, people generally return to their happiness baseline — no happier or less happy than they were before. If even the greatest (or worst) day of your life can’t drastically change happiness long term, then simply being a little skinnier ain’t gonna do the trick either.

That’s not true for everything, of course. If your basic needs — food, shelter, safety — are not met, Lyubomirsky said, then changes in your life that fix those problems will increase your long-term happiness. But middle- and upper-class Americans — i.e., the sort of people who have the time to fret about making and keeping New Year’s resolutions — are unlikely to get a permanent happiness boost from a life change.

But that doesn’t mean resolutions are pure hokum — some kinds of changes are associated with increased life satisfaction, said Lyubomirsky and Kennon Sheldon, professor of psychology at the University of Missouri.

For instance, why you decide to make a change matters to how you’ll feel about it later, Sheldon told me. Researchers talk about an idea called “intrinsic motivation” — that is, changes you choose to make because you just plain enjoy them. If you make a resolution to do something that you like doing, not only is it more likely to make you happier over the long haul — you’re also more likely to keep the resolution.

Unfortunately, it’s hard to get intrinsic motivation from things like “stop smoking” or “eat fewer frozen Zebra Cakes.” In those cases, you’re literally abandoning a thing that feels good because you think you ought to, not because you enjoy giving it up. But there’s still a way to get the same kind of bump, Sheldon said. “Identified motivation” is basically about attaching deep meaning and personal identity to a choice — this is who I am and what I do. And it’s associated with happiness, too. Don’t just give up Zebra Cakes. Turn yourself into the kind of person who doesn’t eat Zebra Cakes.

It can be hard to muster up identified motivation out of thin air, though. And, without it, even an important life change that you know you ought to make can end up reducing your overall happiness. That’s a part of why it’s so hard to stop smoking, Sheldon said. Many people want to stop smoking, but they also really like smoking and aren’t particularly invested in taking on the identity of “nonsmoker.” They’re trying to stop because they know they should, not because they want to. Compare that to people who choose to do a really hard thing they’re also really excited about — like the people Sheldon is currently studying who decided to hike the Pacific Crest Trail — a 2,600-mile path from Mexico to Canada. “These were people who were walking the whole thing in one summer,” he told me. “The ones who developed more identified motivation during the trip were the ones who finished it. That was more important than starting with identified motivation.” Of course, he added, even the people who finished didn’t necessarily end up happier afterward.

So maybe the biggest thing to take away from the research on changing your life is that you should start any resolution with a clear understanding of what your goals are and what you think you’ll get out of achieving them. With the right motivation, you really can change what you’re doing in your life and who you think you are. But don’t expect that it will necessarily make you happier. Those two things aren’t one and the same.