This is the moment of the quantified self.

Such a moment isn’t driven only by the Apple Watch, which the company markets for its self-tracking ability; nor is it entirely the doing of fancy pedometers like Fitbit and Jawbone, or  the dubious sleep-quality measuring apps. This moment is also the product of an age of corporate-enforced quantification, whether through metrics-obsessed journalism or employee biometric scanning programs that cost $4,000 to opt out of.

It’s not clear which parts of our measurement moment will prove faddish and which will stick. But in the meantime, new evidence suggests that when we do measure things, we might not enjoy them as much. A new study in the Journal of Consumer Research seems to indicate that measuring an activity, whatever it is, decreases people’s motivation to keep up with it.

In other words, it proposes that the more you quantify something that’s rewarding for its own sake, the less likely you are to enjoy it—and the less likely you are, too, to do more of it. Across a series of experiments, Jordan Etkin, a marketing professor at Duke University, found that people’s intrinsic motivation to do something—whether it be coloring, reading, or walking—declined once it was measured.

In one experiment, researchers had 105 undergrads color in shapes for a few minutes, then rate how much they enjoyed it. Those who got numerical feedback on their works in progress—“you have colored one shape,” etc.—colored more shapes but reported enjoying it less.

In two other experiments, researchers gave about 100 people pedometers to wear through the day. In the same pattern as the colorers, those wearing the pedometers walked more than their peers without pedometers but enjoyed it less, even when they didn’t have access to the device’s step count. And in the final two experiments, 300 students reading for a brief period of time read more than a control group, but enjoyed it less, when they could see how many pages they had processed.

“There’s a major stream of research in psychology that looks at how providing external rewards can undermine the inherent fun or enjoyment of doing something,” Etkin told me. “The classic example: If you have kids—kids like to color, they’re coloring—if you give them an award for coloring, that makes them enjoy coloring less and makes them want to color less in the future.”

But she cautioned that if someone was doing an activity for a specific reason, having access to the data could actually make them more likely to do it.  

“The reason why you’re engaging in the activity matters a lot. If it’s something that’s really goal-directed—I’m walking to lose weight, I’m walking because I want to be healthier—if walking serves some goal that I have, then measurement doesn’t make it feel less enjoyable. In fact, it can have some benefits for enjoyment,” she told me.

She added: “The negative effects of measurement are really where you were just doing something for fun. Measurement makes it not fun.”

A few words of caution. Like many psychological studies, Etkin’s subject base of American undergraduates was WEIRD, an acronym for subjects that are overwhelmingly Western, educated, and from places that are industrialized, rich, and democratic. Because the study was based on a very specific population, it’s difficult to say whether the findings would hold across the board. Psychological science right now is also struggling with questions of replication, wherein some results and assessments previously judged as core to the field could not be recreated in a clinical laboratory setting.

The earnest, Fitbit-wearing weight watchers—the people who are tracking their steps for some reason other than pure fun—may not care about all these findings. But for those making products that depend on people quantifying new and different kinds of activities, Etkin’s findings should present a cautionary story.