Every January, millions of people set out with the best intentions to change. They’ll go to the gym this year, eat healthier, save money, learn a new skill — the list goes on. But most people — about 90% — give up on their New Year’s resolutions within the first few weeks of the year.

Turns out, it’s really difficult for people to change.

“Research shows that we all tend to break our long-term goals or slip up under certain circumstances,” said Naomi Sadeh, associate professor in the Department of Psychological and Brain Sciences at the University of Delaware. “So if you've had a really stressful day or you're very tired — those sorts of environmental situations can make it more likely that we'll do something impulsive, like break our diet, for instance.”

Part of the reason it’s so hard to make long-term changes is that humans are wired to prioritize instant gratification over delayed rewards. In other words, when posed with an option, we tend to pick the easy choice with an immediate outcome to satisfy a need today instead of delaying gratification for a bigger reward — we splurge on items we don’t really need instead of saving money, order takeout instead of cooking a healthy meal, or binge-watch a TV show instead of going to the gym.

“With impulsivity and with breaking New Year's resolutions, often it's when people tend to opt for that sooner, smaller reward over the longer, bigger reward,” Sadeh said. “The sooner reward is really tempting, even if it's not as satisfying in the long run as the longer goal or bigger goal that you had.”

The timing of New Year’s resolutions also isn’t always ideal. According to Philip Gable, professor in the Department of Psychological and Brain Sciences, a lack of commitment is one reason why many people fail to achieve their goals.

“New Year's resolutions sometimes lack in commitment,” he said. “It's just this time of year when people feel like they should make a resolution, as opposed to other times in the year when it's less common but maybe more meaningful, like if you get a doctor's report and realize you need to change that aspect of your life.”

When people set goals, they tend to feel very motivated for a few days and falsely assume they’re committed to their goal. But as soon as that motivation wears off, they give up.

“There's potentially a mismatch in the timing of your goals,” said Rob West, interim chair and professor in the Department of Psychological and Brain Sciences. “Your goals are immediate, they're conscious, they're volitional. You have those in the moment, and they can be developed and abandoned quickly. But habits take a considerable amount of time and repetition.”

In order to be part of the 10% of people who keep their New Year’s resolutions, Gable said to break down big goals into small, achievable steps. 

“I think a lot of times with goals, people will commit to a very big goal and not realize the smaller steps they need to take to achieve that goal,” Gable said. “If we have too big of a goal, we get emotionally distressed when we can't do it, or we fail because we set too big of a goal. Or maybe we couldn't think through all of the elements required to meet that really big goal. So starting small gives us something achievable, and then that gives you a platform to go to the next thing.”

When it comes to forming new habits, repetition is key.

“In your natural setting, or even in controlled settings, habits are going to develop slowly,” West said. “You don't roll out of bed and say, ‘I'm going to have a new habit today.’ That's not the set of cognitive mechanisms by which we develop habits. They are acquired over time through repetition.”

Sadeh said people are more likely to repeat a new behavior if it’s reinforced in a positive way, so making new habits rewarding is another way to ensure they stick — for example, watching your favorite TV show only when you’re on the treadmill. Social support is also important. So whether it’s working toward a goal with a partner or joining an online group, it’s helpful to have other people around who are working on the same goal, especially on days when motivation is lacking.

Many people underestimate how hard it is to stick to a resolution, so planning ahead is also important. Sadeh suggests leaving notes around your home that remind you of your goal and also preparing for the moments when it might be tempting to give up — for example, making healthy meals ahead of time in preparation for nights when you might be too tired to cook dinner.

It’s also important to remember not to be too hard on yourself if you do slip up.

“It’s hard to create new habits,” Sadeh said. “It happens every year — we all have good intentions and then life gets in the way. So it’s important to be kind to yourself when you make mistakes or have lapses in your plans. If you just go down the rabbit hole of feeling guilt and shame, that's not going to help in terms of your long-term goals. Just expect that there will be lapses and accept that and be kind to yourself in those situations.”