According to a new study, the younger the adult, the worse they are at controlling their impulses. Published in the journal Emotion last month, the study shows that “the biggest predictor of successfully resisting your desires is age,” said Daisy Burr, the lead author and a Ph.D. candidate in psychology at Duke University.

You may be wondering whether time just erodes our urges so that there’s not much left to resist as we age. Nope. A study published in 2016 found that strong desires for leisure, sleep and sex, among other pleasures, endure at least until age 55. “What is even more interesting was that older adults also experience stronger desires than younger people. Yet they are still much better at resisting them,” Ms. Burr added.

Three times a day, the researchers sent smartphone alerts to the study’s participants, 122 adults between 20 and 80 years of age. Whenever their phones pinged, the participants had to rate how they were feeling and whether they were experiencing hankerings for food, drink, alcohol, cigarettes, social contact, entertainment, shopping, sex, sleep, social media, tobacco, drugs, exercise or work. They were asked to rate how powerful their urges were, from no desire at all to irresistible, and how much conflict they felt before giving in to their impulses or resisting them.

These repeated assessments continued for 10 days. “When you measure people multiple times a day you get how much they change from hour to hour,“ said Gregory Samanez-Larkin, one of the authors of the study and a professor of psychology at Duke. He wanted the study to reflect the emotional ups and downs of real people as they moved through their day, not just volunteers who come into a university lab, who may be happier and healthier than other people in the first place. How their moods affect their ability to tamp down their desires was another big question, he said.

Prof. Samanez-Larkin explained that previous experiments had shown that older people tend to be happier, and the new study confirmed that finding: “People at older ages had more positive emotions and fewer negative emotions, and their emotional experiences were more consistent.” But which age group was more emotionally solid and showed better mastery of their urges? “The people who experience the most emotional instability are in their 20s,” he said, a volatility that gradually declines with every decade.

Though older people experienced intense desires, they were also more expert at delaying gratification when they put their minds to it. “It’s effortful,” said Prof. Samanez-Larkin. “I think older adults know when it really matters. It’s like choosing your battles.”

The study is small and tells us less about a specific generation—such as whether Gen-Xers or Baby Boomers are more impulsive or happier—and more about what happens in every generation. Just as we’re gradually losing our hair, our short-term memories and our athletic prowess, we gradually gain emotional stability, life satisfaction and self-control. And that’s a pretty good trade-off.