Skip to main content

Romantic Relationships: The Filter Theory

Angel is currently studying for her A-levels (English, Sociology and Psychology) in the hopes of going to university next year.

Everything you need to know about the filter theory.

Everything you need to know about the filter theory.

The filter theory explains how we narrow down potential partner candidates. Research conducted by Kerkhoff and Davis provide support for the theory, and many celebrate the usefulness of the explanation. However, others criticise it for lacking enough evidence to support the claims made.

What Is the Filter Theory?

Kerckhoff and Davis' filter theory argues that we select romantic partners by using a series of filters to narrow down suitable candidates. The first filter is social demography, the second is similarity of attitudes and the final one is complimentary of needs.

  • Social demography - the first stage refers to variables such as age, gender or location which determines the probability of meeting someone in the first place; we are more likely to start a relationship with those we feel similar to.
  • Similarity of attitudes - those who don't have similar attitudes and values will be filtered out. Kerckhoff and Davis argue that similarity of attitudes is of central importance to beginning a stable and long-lasting relationship.
  • Complimentary of needs - couples with complementary needs provide mutual satisfaction for each other so their relationship is more likely to be successful. For example, a person who wants to care for someone and someone who wants to be cared for have complementary needs. It's not so much about opposites attracting, but rather a series of characteristics that harmonise and compliment each other.

If a candidate doesn't fit the criteria of the first stage, they are 'filtered out.' If they pass they are then assessed by the second stage and so on.

Kerckhoff and Davis

To test their theory, they conducted a longitudinal study of 94 couples who completed questionnaires assessing attitudes and values, and complimentary of needs. They also did a questionnaire seven months later.

Initially, similarity of attitudes appeared to be related to partner closeness. However, when the couples were divided into short-term (less than 18 months) or long-term (more than 18 months) they found significant differences. For the short-term relationships, similarity of attitudes was most important, but for long-term complimentary of needs was. These findings support the filter theory as it shows how couples go through a series of filters. Short-term relationships ended because they were 'filtered out' in the second stage whereas long-term relationships reached the third and final stage.

Do you support the filter theory?

Do you support the filter theory?

Support for the Filter Theory

Supporting the filter theory, Duck argues that it is a valuable tool in predicting whether a relationship will 'work' or not. He points out how people use a series of strategies to gather information (such as questions or provoking disagreement on certain topics) this allows individuals to filter out unsuitable partners. Duck says that filtering prevents people from making the wrong decisions; it is ultimately an essential and effective tool to select a suitable romantic partner.

Research has found that perceived similarity is more important than actual similarity. Hoyle found that perceived similarity with an individual was a better predictor of relationship success than real similarity. Tidwell et al further support this argument with a study on speed dating. Participants completed a questionnaire measuring perceived and actual similarity. They revealed that perceived similarity predicted romantic liking more strongly. This research supports the second stage of the filter theory.

Limitations of the Filter Theory

One limitation of the filter theory is that there is a lack of research to support it. Levinger et al failed to replicate the results of Kerckhoff and Davis implying that their findings aren't reliable enough to be used to support the theory. Levinger's study of 330 stable couples replicated the same procedure, however, they found no evidence to suggest that similarity of attitudes or complimentary of needs influenced the success of a relationship. This failure indicated that the filter theory is not reliable, although Levinger suggests that the reason for this failure may have been due to social change during the two-year gap between the studies.

Contradicting research for the complementarity of needs hypothesis proposes that similarity is actually more important. Dijkstra and Banelds studied 760 single participants who were looking for a long-term partner. Their own personality was measured whilst they rated personality characteristics they found most desirable. Although individuals expressed a desire for partners with complementary characteristics, the researchers found strong correlations between their own personality and their ideal partners. These findings imply that although people say they want a complementary partner, similarity is more important when deciding on an ideal partner.

Finally, another criticism of the filter theory is that attitudes and values are constantly changing; in many instances, people are not aware of their partner's values, needs or attitudes as they often change over time. Thorton and Young-DeMarco found that over a few decades, attitudes toward marriage changed with fewer people wanting to get married. This, amongst dozens of other beliefs that have changed, show how attitudes aren't fixed.

The filter theory, though accepted by many, does have its complications.

The filter theory, though accepted by many, does have its complications.

To Conclude

The filter theory proposes that in order to select a suitable partner, we filter out potential candidates through three stages: social demography, similarity of attitudes and complementary of needs.

Although research such as that of Kerckhoff and Davis support the theory, many argue that the study isn't reliable as other researchers have failed to replicate it.


Cardwell, M., Flanagan, C. (2016) Psychology A level The Complete Companion Student Book fourth edition. Published by Oxford University Press, United Kingdom.

© 2018 Angel Harper


Angel Harper (author) on November 11, 2018:

Dora Weithers, I'm glad you enjoyed learning about it! Although the theory does explain short term and long term relationships, I think other factors such as age, gender or even religious beliefs may affect duration as well. Thank you so much for reading and leaving a comment!

Dora Weithers from The Caribbean on November 11, 2018:

Thanks for introducing this filter theory. Interesting how similarities and needs factor in different lengths of relationships. I can see how similarities provide short term attraction. Something to think about!