Interdependence Theory: Why Do We Stay in a Relationship?

From the Lecture Series: Understanding the Mysteries of Human Behavior

By Mark Leary, Ph.D., Duke University

Interdependence theory explains that people understand the cost of a relationship and put up with it, but when this cost passes their limits, they stop feeling satisfied. The point is, some people do understand that these costs are way beyond their limits, but still stay. They are not happy, but they do not leave. Why do some people stay in such relationships?

Happy African American couple eating popcorn while sitting on a sofa at home.
The interdependence theory explains how the success of a relationship depends on costs, rewards, and expectations. (Image: LightField Studios/Shutterstock)

Happiness is not equivalent to staying in a relationship and not getting a divorce or breaking up. Many people stay in unhappy relationships until death doth them apart, but not because they love each other so much. Why then?

Interdependence Theory

The interdependence theory explains that people find relationships satisfying up to a certain point. Close relationships are rewarding in many ways: from companionship to help when needed, from psychological and physical intimacy to financial help, and from helpful advice to birthday and Christmas presents.

Happy young couple with a gift box.
Close relationships are rewarding in many ways. (Image: George Rudy/Shutterstock)

But all this comes at a cost. These costs vary. They can be difficult cases of being abused, having an addicted partner, or a partner who wastes money and resources. However, normal costs are usually smaller: ordinary annoyances, aggravations, frustrations, and conflicts. Sometimes, they have to compromise with a partner in ways that they do not really like.

The overall outcome of a relationship is calculated simply by subtracting people’s costs in a relationship from the rewards that they receive. Although it may seem that having relationship profits leads to happiness, that is not always the case.

This is a transcript from the video series Understanding the Mysteries of Human Behavior. Watch it now, on Wondrium.

The Comparison Level

According to the interdependence theory, every person has a standard for deciding on the level of profit in a relationship. This criterion is called the comparison level and is defined as the minimum value of the outcomes that one thinks they deserve from a relationship.

A relationship is a happy one if the outcome goes beyond the comparison level. The further it goes in exceeding that level, the more satisfaction would follow. On the other hand, if the comparison level is not reached, dissatisfaction occurs. It does not matter if the rewards are higher than the costs; what matters is that the comparison level doesn’t reach the satisfactory level.

The profit must meet the individual’s expectations to be satisfying. Thus, the relationship world gets complicated since people’s expectations and criteria differ.

Learn more about what makes people happy.

Reality and Perception

Research shows that Americans are less happy with their marriages compared to 25-30 years ago. They report more problems, but it is not clear if the problems are real or just perceived as problems.

Of course, life has become more complicated and difficult in some senses. Yet, relationships may not have changed significantly in terms of problems, while people’s expectations might have. People expect more.

Studies show that people who begin their married life with the highest expectations of how wonderful it’s going to be are often the least satisfied and fulfilled a few years later. On the contrary, those with realistic expectations were the happiest couples after four years of marriage. Surprisingly, not all unhappy marriages ended in divorce.

The Comparison Level for Alternatives

A person might not get enough profit in a relationship, have unfulfilled desires, and be far away from reaching their personal comparison level. But none of these make them leave. They stay with an alcoholic or abusive partner, or with one who is too different from them to make them happy. Why?

The second standard in relationships is their comparison level for alternatives. This is the lowest level of outcome that people expect to get by leaving their current relationship and moving to the best alternative situation. In fact, it is the minimum level of outcome that people tolerate in a relationship.

Woman choosing between family or parental responsibilities and career or professional success.
The comparison level of alternatives shows a person what they will get if they leave the relationship and what they will lose. (Image: GoodStudio/Shutterstock)

In a happy relationship, both comparison levels are exceeded. Both individuals are satisfied and do not think that they can do better elsewhere. However, when a person feels like leaving the relationship will reduce the rewards even further, they prefer tolerating things and having the rewards, even if they are low.

Learn more about why hurt feelings hurt.

Relationship Calculations

As unromantic as it may seem, calculation is the basis of decision for people on whether to stay in a relationship or leave it. Costs and rewards matter, as well as how much they have invested in the relationship.

The comparison-level criteria are key roles, as they determine the happiness and success of a relationship.

Common Questions about Interdependence Theory

Q: What are the examples of relationship costs?

Little annoyances, aggravations, frustrations, and conflicts, along with sometimes having to compromise with a partner in ways that we do not really like, are all examples of costs. The interdependence theory explains how these costs are tolerated until they reach our limit.

Q: Do happy relationships have no cost?

All relationships have costs. According to interdependence theory, each of us has a criterion for judging whether we are making enough of a profit in our relationships with other people or not. Up to that limit, everything is fine.

Q: What is the comparison level?

According to interdependence theory, each of us has a criterion—a standard—for judging whether we are making enough of a profit in our relationships with other people. This criterion is called our comparison level.

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