Billions of people deal with a nail-biting habit at some point in their lives. Many will go to great lengths to try to stop. And while not all of us are nail-biters, most of us do have a habit we'd like to kick. So what's the best way to break one?

Research shows that intentions alone often fail to lead to long-term behavior change. This isn't to say you can't break a habit. Rather, by understanding the basis of habits, you can create better plans for changing them. For example, we know habits are often affected by environments and routines. Lying in bed may cause you to endlessly scroll through your phone, or watching TV on the couch may lead you to grab a sugary snack.

One of the most effective ways to manage behavior is to identify these locations or times of day. Then try to modify them by changing your routine or creating obstacles that make it more difficult to perform the habit in that space. Moving, switching jobs, or even starting a new schedule, are particularly great times to break a habit or build a new one.

One 2005 study tracked university students' exercising, reading, and TV-watching habits before and after they transferred schools. When students were no longer around old environments and routines, their habits, even the strong ones, significantly changed.

For behaviors like nail-biting, a practice called habit reversal training can be helpful. Developed by psychologists in the 1970s, the aim is to change a habit by replacing it with another one that's less detrimental. The training requires you to analyze and understand your habit cues, so you can effectively step in at the right times. For example, if you tend to bite your nails at work, keep a fidget toy at your desk in advance. Then, if a stressful email comes in, use the toy when you feel the urge to bite your nails.

Breaking a habit takes time, so remember to give yourself grace and have patience through the process.

For 83 years, Betty Grebenschikoff believed her best friend from Germany was dead. But just a few weeks ago, there she was, standing in a hotel room.

At the age of nine, they shared a tearful hug in a Berlin schoolyard when their families were forced to leave the country because of World War II. They both thought that would be their final hug. But after more than eight decades apart, the two women, who are now 92 years old, embraced once again.

The survivors of the war had searched for each other for years, collecting and seeking information from anyone who might know something. They had no luck, mainly because both women changed their names later in life.

It was not until an indexer (检索程序) from a nonprofit organization founded by Steven Spielberg, which preserves information of these survivors, noticed similarities in their information that the two women are linked together. For the first time, Grebenschikoff who lives in Shanghai now, got to know what happened to her long-lost childhood best friend: Wahrenberg and her family went to Santiago, Chile, where she still lives today.

With the help of the organization, the two women and their families reconnected on the Internet. Talking in their native German, they promised to meet in person, and one year later, they finally did.

As Grebenschikoff went to meet Wahrenberg at her hotel room, they hugged for the first time in 83 years. "It was as if we had seen each other yesterday," Grebenschikoff said."It was comfortable. "Wahrenberg had the same feeling, "It was very special that two people, after 83 years, still love one another." The women spent four days together. They went shopping, shared meals and, mostly, talked for hours - making up for the lost time. "We're not the girls we used to be when we were 9, that's for sure, but we kept giggling like we were little kids." Grebenschikoff said. "It was such a joy for both of us."

Every summer, the calls of thousands of swamp sparrows can be heard across North America's wetlands. These little brown birds know only a few songs, but they know them very well. In fact, their musical set list probably hasn't changed much for centuries.

Like humans, baby swamp sparrows learn to communicate by copying adults. From a young age, they learn to copy, or mimic, songs sung by their elders. "Swamp sparrows very rarely make mistakes when they learn their songs," says biologist Robert Lachlan. In fact, their mimicry is so accurate that the music changes little between generations.

Just like children, the sparrows don't remember every song they hear. Lachlan says. "They don't just learn songs at random; they pick up commoner songs rather than rarer songs." In other words, they learn songs they hear most often. It's an example of a strategy that scientists call conformist bias. Until recently, this learning ability was thought to be special only to humans.

Between 2008 and 2009, Lachlan's research team recorded the calls of 615 male swamp sparrows across the northeastern United States. The researchers used computer software to break each song into a collection of notes, or syllables. They then measured the differences between the tunes.

The research revealed that only 2 percent of male sparrows sang a different song from the standard tune. The combination of accurate mimicry and conformist bias allows the birds to create traditions that last for centuries. "With those two ingredients together, you end up with traditions that are really stable," says Lachlan. "The song-types that you hear in the marshes（湿地）of North America today may well have been there 1,000 years ago." Lachlan's study is also among the first to measure the longevity of song traditions within a bird species.

The findings are really exciting, says scientist Andrew Farnsworth. He hopes that future research will evolve from these studies. For example, scientists may be able to identify how other animals are able to preserve their cultural traditions. "Seeing the potential for it in other organisms is super cool," says Farnsworth.