WENDY WOOD: Five myths about habits

Each year, nearly 50 percent of Americans vow to change their behavior with the new year, resolving to lose weight, get more organized or fall in love. Odds are, they won't succeed. Just 8 percent achieve their New Year's resolutions. A quarter give up after the first week.

Many New Year's pledges involve trying to establish new habits or conquer bad ones. And there's a lot of misinformation swirling around about how habits are formed and how they can be changed. Here are some of the most common myths:

1. A lack of willpower is to blame for our bad habits.

A third of Americans say they lack the self-control they need to accomplish their goals. About a fourth attribute trouble sticking to a diet, for example, to personal character defects such as laziness.

In truth, though, many of our behaviors are not guided by self-control. Half the tasks we perform daily are things we do without thinking. And studies show that people with high levels of self-control aren't constantly battling temptation -- they're simply relying on good habits.

2. Apps can help us change our behavior.

Apps like Fitbit, MyFitnessPal and BookLover promise to help us change our habits by tracking our good (or bad) behavior. And some websites say they work, running lists like "17 bad habits you can kick using nothing but a smartphone" or "Mobile apps that can help you kick your bad habits."

But most apps simply monitor what you're doing, which doesn't necessarily lead to behavior change.

3. It takes 21 days to form a new habit.

This idea stems from a popular 1960s book by Maxwell Maltz, and it's often repeated today. Self-help books promise that you can fix your marriage, jump-start your exercise routine or cure your money woes in just three weeks.

In truth, there's no magic number when it comes to establishing habits. They are created slowly as people repeat behaviors in a stable context. Simple health behaviors, such as drinking a glass of water before each meal, had to be repeated for only 18 days before people did them without thinking, according to one recent study. Others, such as exercise, needed closer to a year of repetition. Researchers found that it took an average of 66 days for a new habit to form.

4. The best way to change a habit is to set realistic goals.

This is a mistake. Modifying our environment lets us remake our behavior without over-relying on willpower. Unwanted habits can be disrupted by changing the cues that activate them.

5. Learning about the benefits of new habits helps change our behavior.

Research has repeatedly shown that changing knowledge and intentions does not translate into changing habits. Habits are formed through doing. And the long-term memory systems involved in habit formation don't shift with new resolutions.

In our research, we've found that old habit associations endure, and hinder behavior change, even after people adopt new intentions. For example, once you see a prompt to surf the Web, it's hard to get that out of your head and instead focus on your resolution to stay organized.

Wendy Wood is a professor of psychology and business at the University of Southern California.

This story was originally published January 2, 2016 at 7:13 PM with the headline "WENDY WOOD: Five myths about habits ."