If you’re reading this at a desk, do me a favor. Grab a pen or pencil and hold the end between your teeth so it doesn’t touch your lips. As you read on, stay that way—science suggests you’ll find this article more amusing if you do. Why? Notice that holding a pencil in this manner puts your face in the shape of a smile. And research in psychology says that the things we do—smiling at a joke, giving a gift to a friend, or even running from a bear—influence how we feel.

This idea—that actions affect feelings—runs counter to how we generally think about our emotions. Ask average folks how emotions work—about the causal relationship between feelings and behavior—and they’ll say we smile because we’re happy, we run because we’re afraid. But work by such psychologists as Fritz Strack, Antonio Damasio, Joe LeDoux shows the truth is often the reverse: what we feel is actually the product, not the cause, of what we do. It’s called “somatic feedback.” Only after we act do we deduce, by seeing what we just did, how we feel.

This bodes well, at first blush, for anyone trying to change their emotions for the better. All you’d need to do is act like the kind of person you want to be, and that’s who you’ll become. (Call it the Bobby McFerrin philosophy: “Aren’t happy? Don’t worry. Just smile!”) But new research, published in the Journal of Experimental Social Psychology by Aparna Labroo, Anirban Mukhopadhyay, and Ping Dong suggests there may be limits to our ability to proactively manage our own well-being. The team ran a series of studies examining whether more smiling led to more happiness. One asked people how much smiling they had done that day, and how happy they currently felt. Other studies manipulated the amount of smiling people actually did, either by showing them a series of funny pictures or by replicating a version of the pencil-holding experiment. As expected, across these experiments, the researchers found that the more people smiled, the happier they reported being.

But only some people. Surprisingly, for a section of the population, smiling actually reduced well-being. The more these people smiled, the less happy they were. This is like finding that there are some diners who, after consuming a four-course meal, feel less full!

Who are these people for whom extra smiling fails to generate corresponding increases in joy? In the answer lies the ultimate irony. It turns out that the gloomiest people were those who believed in precisely that somatic feedback hypothesis I described above. People who realized, in other words, that you can “smile to feel happy” (called proactive smilers) were exactly those who did not enjoy the benefits of the theory they espoused. On the other hand, for those who believed that smiling is a genuine indicator of mood—those who subscribed to commonsense notions about the causal order of action and emotion (reactive smilers)—smiling boosted happiness.

How does understanding the benefits of proactive smiling eradicate its effect? It remains a matter of scientific opinion. What’s likely is that knowing too much about somatic feedback throws a wrench in the circuitry, undercutting the message the body sends to itself. At first, the brain says, “I’m smiling; I must be happy!” But upon learning that smiling can be a proactive strategy, this turns into, “I’m smiling; I must be trying to make myself happy—I must be sad!”

What’s left is this Catch-22 in which extra smiling will help only if you don’t realize it will. To reap the benefits of proactive behavioral strategies, you can’t think too much about them. In the same way you can’t set your alarm clock forward ten minutes to trick yourself into punctuality, artificially forcing a smile isn’t going to do much for your happiness. Too much knowledge and the jig is up.

This points to a more general insight about human wellbeing. Life is full of instances in which trying too hard—to be cool in high school, to enjoy a comedy show, to be admired by coworkers—immediately subverts the goal. Attaining objectives such as these depends upon approaching them at a tangent.

The “pursuit of happiness” would thus seem best accomplished by indirect methods. Successfully absorbing yourself in the mundanities of everyday life may eventually lead to the deepest fulfillment. But of course, trying too hard to achieve this absorption will undermine the very thing you are trying to attain. At this point the impulse might be to throw up your hands in resignation. Then again that resignation—that acceptance—may be precisely what we’re looking for.