I’ve been trying to quit biting my nails forever, but all techniques have failed. If I apply nail polish, I leave my nails alone but I bite my cuticles. Then when I remove the nail polish, I’m back to square one and the nail biting resumes instantly. I even tried that bitter-tasting nail polish that’s supposed to keep you from putting your fingers in your mouth. A waste of money.

Believe me, I want to quit. I find nail biting disgusting, especially because I live in New York City, where the bubonic plague was found on the subway. All this is to say that I was beyond excited when I read a positive New York Times review of a wearable device that claims to break bad habits, including nail biting. I decided to try it right away, even though it sounded like a torture machine. And it was.

The so-called Pavlok is like a Fitbit you wear on your wrist, but instead of counting your steps, you can use it to give yourself a quick electric shock every time you’re biting your nails (or smoking a cigarette or eating ice cream). Whatever bad habit you have, the Pavlok promises to break it by zapping you out of it.

The device is named for the Russian Nobelist Ivan Pavlov, who discovered classical conditioning. In classical conditioning, a neutral stimulus (like a bell) is paired with a biological stimulus (like food), resulting in a reflex (like salivation) whenever the once-neutral stimulus is presented. Pavlov’s work was expanded by the American psychologist BF Skinner into operant conditioning, where a behavior is modified by reward or punishment.

The device, though named for Pavlov, works on Skinner’s operant style. Here’s an example of how operant conditioning works: If you’re shocked every time you bite your nails, eventually you’ll associate nail biting with the painful shock and, ideally, avoid the behavior. This was developed into what is called aversion therapy, which is sometimes used to treat addiction and compulsive behavior.

I tried the Pavlok for over a month and my conclusion is: it doesn’t work. Sure, the first week I was very methodical, zapping myself every time I put my fingers in my mouth. My nails even managed to grow 0.5 inches long and stop hurting. But at the end of week one, I resumed biting my nails more fiercely than ever and I did something I found extremely liberating: I ignored the Pavlok on my wrist.

And that’s the major flaw of the device: the Pavlok isn’t smart enough to know when you’re actually biting your nails, administering the electric shock. You have to press the device and give yourself the shock. So I just stopped doing it. The Pavlok’s flaw is the major flaw of aversion therapy in general — and the reason why aversion therapy isn’t used that much in behavioral psychology, experts say. (People respond better to rewards than punishments.)

"Aversion therapy is very difficult to sustain," says Bankole Johnson, chair of the department of psychiatry at University of Maryland School of Medicine. "It requires the person to maintain the aversive quality that is associated with it. It tends to be extinguished pretty quickly."

The Pavlok comes with a little black book in the packaging that says "evidence" in all caps on the cover. If you read through it, there are all these amazing testimonials of people who swear to have quit smoking, nail biting, teeth grinding, and snacking thanks to the Pavlok. When I asked Maneesh Sethi, Pavlok’s creator, if the device had been used in any clinical trials, he sent me the link to a study conducted at University of Massachusetts Boston and funded by Pavlok.

In the study, which was not published in a peer-reviewed journal, eight people tried to quit smoking using the device. After 10 days, six of them had stopped smoking. The study is obviously too small and short to indicate true health benefits; it also doesn’t say what happened to the participants after the study was over. Did they stay smoke-free? Did they relapse, as is often the case when smokers try to quit? Did they keep shocking themselves forever?

"An interesting study but the results are too preliminary to reach any firm conclusions," says Johnson.

Apart from the scant scientific evidence, I found the Pavlok to be actually painful — and faulty in a way that made me uncomfortable. Through the app, you can set the intensity of the shocks — from 45 volts to 450 volts. When I first started using it, I set the intensity at 90 volts, just to be on safe side, but even then the electric shock made me jolt. I felt an unpleasant tingling in my fingers. But the worst thing is that, somehow, the intensity of my Pavlok kept changing by itself. So any time I pressed the device, I didn’t know if I was going to get 45 volts or 450 volts.

I didn’t like that. At all. When 450 volts pierce through your wrist, you feel like a bug has just bitten you. The pain lingers for a few minutes. My colleague Paul Miller shocked himself twice with the maximum intensity and said he felt bad for the rest of the day.

Through the app, you can also set the Pavlok to vibrate automatically every time you bring your hands to your mouth. That function did help me notice when I was about to bite my nails, but unfortunately it works only for one hand at a time (you can set it either for the right or the left hand, not both). It’s also very annoying, because the Pavlok kept vibrating every time I brought my hand to my face — even when I was just sipping tea or answering my phone. (Sethi says that the company is working on improving this feature.)

The Pavlok didn’t work for me, because I didn’t have the willpower to shock myself every time I bit my nails. But if I had the willpower to methodically shock myself, I would probably also have the actual willpower to stop biting my nails in the first place. As psychiatrist Stanton Peele told me: "It has a lot of voluntarism in it, don’t you think?"

It does. So maybe the people who were able to quit smoking using the Pavlok — I’d like to meet them — were able to do so because they have actual self-control. They just needed an expensive gadget (the Pavlok sells for $169) to help them figure that out. Good for them. I feel like Rachel in Friends. Aversion therapy isn’t for me.