Most of us have a strong desire to appear consistent. Consistency is valued in our society and is associated with other positive traits like honesty, stability and intelligence. Similarly, most of us will go to great lengths to fulfill our commitments. Psychologist Robert Cialdini calls these tendencies the Commitment and Consistency Principles.

Why do most of us share these tendencies? Consider the unattractiveness of the contrary – few would want to deal with a counterpart with a reputation for acting inconsistently and leaving commitments unfulfilled.

In the negotiation context, these principles can be a powerful behavioral motivator. Good sales professionals know if they can get a small commitment from a potential customer, a foot in the door so to speak, that customer’s natural tendency will be to act in a manner consistent with their original commitment.

Also, if you discover your counterpart previously acted in a way consistent with the outcome you desire, point it out to them to take advantage of the power of these principles.

Marty Latz is the founder of Latz Negotiation Institute, a national negotiation training and consulting company, and ExpertNegotiator, a Web-based software company that helps managers and negotiators more effectively negotiate and implement best practices based on the experts' proven research.  He is also the author of Gain the Edge! Negotiating to Get What You Want (St. Martin’s Press 2004). He can be reached at 480-951-3222 or Latz@ExpertNegotiator.com.