“You have the right to remain silent. Anything you say or do can and will be used against you in a court of law. You have the right to an attorney. If you cannot afford an attorney, one will be appointed to you. Do you understand these rights as they have been read to you?”

—The Miranda Warning

IN THE SPRING of 1966, a man named Ernesto Miranda was arrested in Phoenix. The police had very little to go on, but they suspected Miranda of kidnapping and raping an 18-year-old woman ten days earlier. The officers interrogated Miranda for two hours and were rewarded for their effort: Miranda admitted to the rape charge and signed a confession paper.

There was just one problem. During the interrogation, Miranda had been alone and at no point was he informed that he had the right to legal counsel.

When the case went to trial, Miranda’s written confession was used as evidence. He was quickly convicted, but his lawyer appealed because Miranda had never been informed of his rights and thus, according to his lawyer, the confession was not voluntary. The Arizona Supreme Court upheld the decision, but eventually the case made it to the United States Supreme Court.

The United States Supreme Court overturned the Miranda ruling by a vote of 5 to 4 because “The person in custody must, prior to interrogation, be clearly informed that he has the right to remain silent, and that anything he says will be used against him in court; he must be clearly informed that he has the right to consult with a lawyer and to have the lawyer with him during interrogation, and that, if he is indigent, a lawyer will be appointed to represent him.” 1

The Supreme Court had just created a bright-line rule.

The Power of Bright-Line Rules

A bright-line rule refers to a clearly defined rule or standard. It is a rule with clear interpretation and very little wiggle room. It establishes a bright line for what the rule is saying and what it is not saying.

The Miranda ruling is one example. If a police officer fails to inform a defendant in custody of their rights, then the suspect's statements are not admissible in court. Plain and simple. Clear and bright.

Most of us, myself included, could benefit from setting brighter lines in our personal and professional lives. Consider some common examples:

We might say that we want to check email less frequently.

We might say that we want to drink moderately.

We might say that we want to save more for retirement.

We might say that we want to eat healthier.

But what do these statements really mean?

What does it mean to check email less frequently? Are you going to “try to be better about it” and hope that works? Will you set specific days or certain times when you will be unavailable? Will you check email on weekends? Will you process email only on your computer?

What, exactly, is moderate drinking? Is it one drink per week? Five drinks per week? Ten drinks per week? We haven’t defined it, so how will we know if we are making progress? 2

What does it mean to save more? More is not a number. How much is more? When will you save? Every month? Every paycheck?

What does eating healthier look like on a daily basis? Does that mean you eat more servings of vegetables? If so, how many more? Do you want to start by eating a healthy meal once per day? Twice per day? Every meal?

It can be easy to make promises like this to yourself, but they do not create bright lines. Fuzzy statements make progress hard to measure, and the things we measure are the things we improve.

Now, do we need to measure every area of our lives? Of course not. But if something is important to you, then you should establish a bright line for it. Consider the following alternatives:

I only process email between 11AM and 6PM.

I enjoy a maximum of 2 drinks per night.

I save $500 per month for retirement.

I eat at least two types of vegetables per day.

These statements establish bright lines. These statements make action steps precise and obvious. Vague promises will never lead to clear results.

Using Bright Lines to Break Bad Habits

The examples I outlined above focused primarily on building new behaviors, but bright-line rules can be used just as effectively to break bad habits or eliminate old behaviors.

My friend Nir Eyal proposes a similar strategy that he calls “Progressive Extremism.” To explain the concept, Nir uses the example of being a vegetarian. If you were interested in becoming a vegetarian, you might start by saying, “I don’t eat red meat.” The goal is not to change everything at once, but to take a very clear and extreme stand in one small area. You are establishing a bright line on that topic.

Over time, you can progressively move your bright line forward and add other behaviors to the mix. (i.e. “I don’t eat red meat or fish.” And so on.)

How Bright Lines Unleash Your Hidden Willpower

Establishing bright lines in your life can provide a huge boost in daily willpower.

Here are two reasons why:

First, bright lines shift the conversation in your head from one of sacrifice to one of empowerment. When you don't have a bright line established and you choose not to do something, the tendency is to say, “Oh, I can't do it this time.” Conversely, when you do have a bright line clearly set, your response can simply be, “No thanks, I don't do that.” Bright lines help you avoid making just-this-once exceptions. Instead, you are following a new identity that you have created for yourself. 3

Second, by establishing clear decisions in your life, you conserve willpower for other important choices. Here’s the problem with trying to make daily decisions in muddy water: Without bright lines, you must decide whether a situation fits your standards every time. With bright lines, the decision is made ahead of time. Because of this, you are less likely to suffer from decision fatigue and more likely to have willpower left over for work, relationships, and other health habits.