Project Management Institute

How to use the six laws of persuasion


Negotiation is a fact of life for almost everyone in business and a key skill for any successful project manager. Skillful and effective negotiation involves a combination of communication skills, an understanding of both your own goals and those of your negotiating partners, and the ability to use influence and persuasion to create the attitude change and subsequent actions necessary in achieving win-win results.

The goal of any successful negotiation is mutually beneficial results. Whether you are negotiating for procurement terms with a vendor, negotiating to resolve conflicts, or negotiating a project work assignment with a team member, as a project manager you are always negotiating. The degree to which you understand what influence and persuasion are, as well as how well you use them to appeal to the intellect and emotions of the other party, will determine how successfully you sell your ideas and end up in situations in which all parties believe they received a good deal.

Overview: The Six Laws of Persuasion

Persuasion is the ability to influence thoughts and actions through specific strategies. To master this skill, it is necessary to understand some basic principles, called the Laws of Persuasion. There are six laws that make up the Laws of Persuasion, which describe how most people respond to certain circumstances. Psychologist Robert Cialdini wrote the seminal book on the Laws of Persuasion, titled Influence: The Psychology of Persuasion, in which he discusses the prevalent methods of marketing. A great deal of psychological research indicates that human beings are quite predictable in terms of behavior in response to certain stimuli, like advertisements. This is why businesses invest so much money in advertising and why consumers respond to most ads and commercials by buying the products and services they promote. An understanding of the Laws of Persuasion enables you to control how much others unduly influence you and how you can use the laws to your benefit during negotiation.

People are faced with countless decisions every day, and the laws work because they provide shortcuts to making many of those decisions. Some of the best masters of the art of persuasion in negotiation are highly successful salespeople who do their best to not only make the sale, but also to meet the needs of their buyers. As project managers, our fundamental goal is to meet stakeholder needs, so these Laws of Persuasion give us another tool we can use to increase our influence over others as we guide the project to success.

Cialdini’s Six Laws of Persuasion are:

  1.    Law of Reciprocity
  2.    Law of Commitment and Consistency
  3.    Law of Liking
  4.    Law of Scarcity
  5.    Law of Authority
  6.    Law of Social Proof

Law of Reciprocity

In general, people try to repay what they have received from others. If someone gives you something you want, then you will want to reciprocate because now you feel obligated. For example, the address labels you receive in the mail from various non-profit groups requesting charitable donations—even though they are a minor, unsolicited “gift,” sending them out has increased donations to non-profits significantly, because people feel compelled to “return the favor.”

Law of Commitment and Consistency

Consistency of (or at least the appearance of) thoughts, feelings, and actions is important. Once a position has been taken, people tend to stick with it and behave in ways that justify the position, even if it is wrong. Commitment to a decision, position, or cause (however small) is usually easier to increase than it is to abandon. This is why salespeople attempt to get customers to agree with them multiple times; after saying “yes” repeatedly, it is almost impossible to say “no” when it is time for the close or direct request for the sale.

Law of Liking

The old adage “opposites attract” does not hold true when it comes to influence and persuasion. When you like someone, or believe that they are “just like you,” you are more inclined to wanting to please them. Successful salespeople work hard to establish rapport, demonstrating how similar they are to you. They explore your background, noting the similarities to their own. They are people you know; sometimes your friends. Think about the in-home sales parties you may have been invited to, in which your neighbors are providing the testimonials for the product, and you don’t want to disappoint them by not buying something.

Law of Scarcity

If there is a limited supply of an item and only a few are left, then it must be good or popular, which is what the law of scarcity suggests. If something you want becomes “the last one available,” you tend to feel like you have to act immediately or you might miss out. After all, the limited supply must mean that others are buying it, and delaying might mean you won’t be able to get it again anytime soon or maybe never again.

Law of Authority

Advertisers count on the law of authority when using celebrity endorsements or “expert” testimonials. When people you admire promote a product or service, you may think, “If it’s good enough for them, then it’s good enough for me.” In addition, if you use it, you may become more like these “heroes:” better looking, wealthier, and more famous.

Law of Social Proof

Why have television sitcoms used canned laugh tracks for years? Producers wouldn’t use them unless they worked to produce audience laughter and higher ratings. Part of the reason you laugh along anyway, and in spite of yourself, lies in how you decide what socially “correct” behavior is. If you aren’t sure how to act, then you rely on those around you (or in the virtual television audience) to help you find the way to properly react. If others are doing it, then it must be the right thing to do.

Using the Laws of Persuasion

Good negotiations create win-win or mutually beneficial results; that is, results in which all parties believe they have received a good deal. A good deal is not always the same for everyone; negotiators often use different criteria to judge the success of their bargaining outcomes. It is not unusual to find “tough” negotiators using manipulative tactics based on the Laws of Persuasion. To address these tactics, you can call attention to them and steer the conversation toward a more objective solution. You can also try to prevent manipulation based on the laws by establishing ground rules or preconditions ahead of time that will preclude such strategies by using only logical principles as a standard process in negotiation.

Negotiation strategies using the six Laws of Persuasion include the following:

Law of Reciprocity

In projects there are always opportunities to use the Law of Reciprocity. If you have conceded to a demand from a team member on the timing of his or her work on an activity, you can use reciprocity to gain concession from him or her the next time you need something. When negotiating procurements with vendors, the use of limited disclosure and/or a confession for the real reason for a negotiation stance, such as “this is all the money we have,” can provoke a concession from the other party. In general, concessions follow this “tit-for-tat” rule (of course, the lower the “value” of your concession, the better).

Law of Commitment and Consistency

An application of this law would be asking a series of questions to confirm the acceptance of each specific component of a system before asking for acceptance of the whole system. Dale Carnegie, in How to Win Friends and Influence People, called this, “Get the other person saying ‘yes, yes’ immediately.” This occurs when one party asks the other side to make a number of “small” decisions that lead to only one obvious conclusion: to accept the general concession.

Examples of this may also be seen in the use of low-balling tactics, in which intentional, last-minute additions are made to what was originally a low price. The unscrupulous intention here is to get you to “invest” in a product that you initially believed cost less.

Law of Liking

The lesson from the Law of Liking, and from the application of it in sales, is the importance of establishing rapport. When you can establish rapport with your team or other stakeholders, you establish the commonality or similarity between you and improve your opportunity to influence their decisions. You can use the Law of Liking when you need to persuade the team to work harder; if team members believe you are also taking on more work and you really understand their “pain,” then they may be more willing to go the extra mile.

In sales, we often see this in the strategy of “good cop, bad cop.” The “bad cop” clearly opposes your objectives whereas the “good cop” seems to support your position. Naturally, you will tend to identify with the “good cop,” often agreeing with their concessions and goals instead of your own

Law of Scarcity

In projects, there are always constraints on time, money, and people. The Law of Scarcity tells us that the less there is of something, the more it may be desired. You can use your constraints to influence stakeholders to establish priorities in scope or requirements or to negotiate commitment to a higher allocation of a resource’s time to the project.

Law of Authority

Use the Law of Authority to establish your own credentials or credibility early in the negotiation process. When establishing your approach or explaining how or why decisions have been made, link your position to known, respected sources in order to garner credibility.

Law of Social Proof

This law works when you draw on testimonials from satisfied customers or clients (unscripted ones are the best) to encourage new prospects to buy your services or products. The law can also be used to convince your sponsor, customer, or team that others are following similar suggestions as yours. People want to feel like they are parts of an established community that already knows where it is going.

Ethical Issues

Although these laws are neither good nor bad in and of themselves, they can easily be used for positive or negative results. In an environment that seeks to follow ethical rules, the laws should only be used to make lives better. Manipulation occurs when you exploit or deceive others solely for your own gain.


An understanding and skilled use of persuasion are often the keys to success in both your working and personal lives. If you give people what they want, using the six Laws of Persuasion, they will most likely return the favor. When you recognize that you are being manipulated, you can expose the other side’s tactics and counter with an appropriate strategy. This will lead to more effective ways of achieving the goals of all negotiating parties.

Carnegie, D. (1936). How to win friends and influence people. New York: Pocket Books

Cialdini, R. B. (1993). Influence: The psychology of persuasion. New York: William Morrow

Fisher, R., & William, U. (2003). Getting to yes: Negotiating agreement without giving in. New York: Penguin

Hogan, K. (1996). The psychology of persuasion: How to persuade others to your way of thinking. Gretna, LA: Pelican

This material has been reproduced with the permission of the copyright owner. Unauthorized reproduction of this material is strictly prohibited. For permission to reproduce this material, please contact PMI or any listed author.

© 2010, Samuel T. Brown, III
Published as a part of 2010 PMI Global Congress Proceedings – Washington, DC



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