Oral hygiene is important. Unfortunately, both talking about it and doing it can also be boring. So how can you convince people to brush their teeth more often? For starters, you can make it more rewarding. Two Japanese researchers have found that certain types of toothbrush noises make brushing more satisfying, which may make people more likely to do it.

The root of the problem, according to Taku Hachisu and Hiroyuki Kajimoto from Japan’s University of Electro-Communications, is that brushing provides no immediate payoff. In behavioral science terms, it’s a negative reward: when you brush your teeth, you don’t get cavities. But negative rewards are not great motivators. People (and animals) are more likely to do something if there’s a positive reward on the line—that is, if they get something for doing it.

The mental side of oral hygiene is pretty easy to hack. Toothpaste companies have been doing it for ages. Pepsodent was America’s first popular toothpaste. When competitors tried to figure out why, they realized that Pepsodent’s formula included ingredients that happened to create a tingling sensation. Pepsodent users said that tingle was a sure sign that their teeth were clean, and that toothpaste without it was probably just not doing the job. In reality, the tingling sensation was just a side effect, but customers didn’t care. The perception stuck, and today it’s hard to find a toothpaste that doesn’t leave your mouth tingling.

There are a few reward-focused toothbrush technologies already in development or on the market. Hasbro’s “Tooth Tunes” brush plays music when the bristles come in contact with teeth. Scientists also have suggested linking a toothbrush to a virtual aquarium and rewarding good brushers with happy, healthy, reproducing virtual fish. But the rewards offered by these and similar products are pretty abstract; that is, they don’t actually have much to do with brushing.

Hachisu and Kajimoto wondered if they could hack the experience of brushing itself. They set out to determine if they could make the feel and sounds of brushing more satisfying, and to find out if that satisfaction would be enough to motivate people to brush more.

The researchers gave volunteers a special toothbrush outfitted with a microphone that captured the unique sounds of each person brushing their teeth. Then they digitally manipulated the noises to change their volume, pitch, and frequency. The next time they brushed their teeth, the volunteers wore headphones that played the modified brushing noises back to them. The scientists found that simply making small adjustments to the brushing noises made people feel more comfortable and accomplished after brushing. The data also suggested that gradually increasing the frequency of the noises convinced people that their teeth were cleaner.

Hachisu and Kajimoto described their experiments in a special issue of the International Journal of Arts and Technology.

The next step will be to remove the headphones from the equation. The researchers plan to incorporate bone-conduction speakers like those used in the Tooth Tunes brushes.