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The Friendship Formula

Take charge of your relationships.

The Friendship Formula consists of four basic building blocks: proximity, frequency, duration, and intensity. These four elements can be expressed using the following mathematical formula: Friendship = Proximity x (Frequency + Duration) x Intensity.

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Proximity is the distance between you and another individual and your exposure to that individual over time. Proximity serves as an essential element in all personal relationships, for without proximity, no relationships can develop.

People who share physical space are more likely to become attracted to one another, even when no words are exchanged. The key to the power of proximity is that it must take place in a nonthreatening environment. If a person feels threatened by someone being too close, they go “shields up” and take evasive action to move away from that person.

Frequency and Duration

Frequency is the number of contacts you have with another individual over time. Duration is the length of time you spend with another individual over time. Duration has a unique quality in that the more time you spend with a person, the more influence that person has over your thoughts and actions.

Mentors who spend a lot of time with their mentees exercise a positive influence over them. People who have less than honorable intentions can negatively influence the people they spend time with. The best example of the power of duration is between parents and their children. The more time parents spend with their children, the more likely the parents will be able to influence them. If the parental duration is lacking, the children tend to spend more time with their friends and, in extreme cases, gang members.

Duration shares an inverse relationship with frequency. If you see a friend frequently, then the duration of the encounters will be shorter. Conversely, if you don’t see your friend very often, the duration of your visits will typically increase significantly.

For example, if you see a friend every day, the duration of your visits can be low, because you can keep up with what’s going on as events unfold. If, however, you only see your friend twice a year, the duration of your visit will be longer. Think back to a time when you had dinner in a restaurant with a friend you hadn’t seen for a long period of time. You probably spent several hours catching up on each other’s lives. The duration of the same dinner would be considerably shorter if you saw the person on a regular basis.

Conversely, in romantic relationships, the frequency and duration are very high because couples, especially newly minted couples, want to spend as much time with each other as possible. The intensity of the relationship will also be very high.


Intensity is how strongly you are able to satisfy another person’s psychological and/or physical needs through the use of verbal and nonverbal behaviors. Positive intensifiers include mutual gaze, touching, whispering, frequent head nodding, mirroring body posture, frequent smiles, expressive gestures, inward leaning, and intimate self-disclosures during conversations.

Relationship Self-Evaluation

Remember back to the beginning of your current relationship or a relationship you had in the past, and you should now be able to see it developed in accordance with the elements of the Friendship Formula. The Friendship Formula can also be used to identify the parts of a relationship that need improvement. For example, a couple who has been married for several years senses that their relationship is deteriorating, but they don’t know how to fix it. Their relationship can be self-evaluated by looking at the interaction of each of the elements of the Friendship Formula.

The first element to look at is proximity. Does the couple share the same space, or are they separately pursuing their own goals and rarely share physical space together? The second element is the frequency. Do they frequently share time together? The third element is the duration. How much time do they spend together when they do see each other? The fourth element is the intensity. Intensity is the glue that holds relationships together.

The couple may have proximity, frequency, and duration, but lack intensity. An example of this combination is a couple who spends a lot of time at home watching television together but do not interact with any emotion. This relationship can be improved if the couple increased the intensity of their relationship. They could go out on “date nights” to rekindle the feelings they felt for each other when they first met. They could shut the television off for a few hours each night and talk to each other, thus intensifying their relationship.

The combination of the four elements of the Friendship Formula is seemingly endless, depending on how couples interact with one another. In many instances, one member of the relationship travels on business most of the year. The lack of proximity can adversely affect the relationship because it often leads to reduced frequency, duration, and intensity. The lack of proximity can be overcome with technology. Frequency, duration, and intensity can be maintained with the help of email, chatting, texting, Skyping, and social media.

You can also extricate yourself from unwanted relationships by slowly decreasing each of the basic elements of the Friendship Formula. This gradual decrease will let the unwanted person down incrementally without hurting their feelings as much as an abrupt break in the relationship. In most cases, the unwanted person will naturally come to the conclusion that the relationship is no longer viable and seek more rewarding interactions.

Once you know the basic elements of all relationships, you will be able to evaluate existing relationships and nurture new ones by consciously regulating the four relationship elements. To practice relationship self-evaluations, examine the relationships you are in right now and see how the four basic elements are playing a role in affecting those relationships. If you want to strengthen a relationship, think of ways to regulate the Friendship Formula to achieve the desired outcome.


For more tips and techniques to develop and maintain friendships refer to The Like Switch: An Ex-FBI Agent’s Guide to Influencing, Attracting, and Winning People Over.

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