Most People In Long-Term Relationships View These 2 Traits As The Core Of Compatibility

Psychologist Jie Liu discusses what contributes to a relationship's longevity and satisfaction.

By Mark Travers, Ph.D. | April 11, 2022

A new study published in the Journal of Research in Personality suggests that the personality traits of honesty-humility and openness to experience, when assumed to be similar in two people, might lead to higher relationship satisfaction and commitment.

I recently spoke to Professor Jie Liu, the corresponding author for this research from Northeast Normal University, China, to understand why it might be essential to a relationship to view your partner as similar to you in these two capacities. Here is a summary of our conversation.

What inspired you to investigate the topic of relationship satisfaction, commitment as assumed similarity, how did you study it, and what did you find?

I studied assumed similarity in HEXACO personality between intimate partners in my Ph.D., and I found that people assumed higher similarity with their partners particularly in two personality traits: Honesty-Humility and Openness to Experience.

  1. Honesty-Humility comprises characteristics such as being honest, loyal, and sincere versus being boastful, hypocritical, and pretentious.
  1. Openness to Experience comprises characteristics such as being curious, creative, intellectual versus being shallow, unimaginative, conventional.

As previous studies showed that these two personality traits are closely linked to personal values and people tend to assume high similarity with close others in these two traits. I was inspired by these studies, and I am especially interested in whether intimate partners assume higher similarity in these two traits since intimate relationships could be considered as one of the closest forms of relationship.

Thus, we designed the current study, and asked people with intimate relationships to report their personality traits, their partner's personality traits, their relationship satisfaction, and commitment in Denmark, Britain, and China.

Our results show that people tend to view their partner to be like them in all HEXACO personality traits (i.e., Honesty-Humility, Emotionality, extraversion, Agreeableness, Conscientiousness, and Openness to Experience), and they assumed higher similarity in Honesty-Humility and Openness to Experience relative to the other four traits.

Also, people with higher relationship satisfaction and commitment tend to view their partner to be more similar to them in these two traits.

What is important about the distinction between assumed similarity and actual similarity?

Actual similarity means that you are really similar to your partner in reality, whereas assumed similarity means that you think that you are similar to your partner regardless of whether this is the case in reality.

Typically, we have both partners finish two sorts of measurements in personality: one is self-report personality traits (i.e., what is your personality?), and the other is observer report of partner's personality traits (i.e., what is your partner's personality from your perspective?).

The relation between one's self-report and partner's self-report personality is actual similarity, and the relation between one's self-report and one's observer report of partner's personality is assumed similarity. Thus, actual similarity describes what the reality is, while assumed similarity describes what you see.

What are some practical reasons that assumed similarity is able to predict initial attraction and better relation functioning in intimate relationships?

Many studies have shown that similarity, rather than complementarity, breeds attraction. Because people like to be with those who are similar to them, who share their values, characters, hobbies, and interests. Similarity to others confirms the legitimacy of our values, characters, hobbies, and interests, makes us feel better about ourselves, and thus fosters attraction toward those who are similar to us.

Assuming others to be similar to us, regardless of the actual similarity, can help to fulfill our needs for reinforcement. In established relationships, assumed similarity is likely to facilitate daily communication and understanding, reduce conflicts and disagreement, and provide confirmation and reinforcement.

Accordingly, assumed similarity is likely to be positively associated with initiation attraction and better relationship functioning.

However, it is hard to decide the causal relation between assumed similarity and relationship outcomes. Perhaps initiation attraction and better relationship functioning also enhance assumed similarity between intimate partners.

For example, if Sally is attracted to Harry, she is likely to see Harry in the way she wants, which includes viewing him to be similar to her personality-wise. Similarly, in established relationships, if intimate partners have good relationships, they are more motivated to view their partner in the way they want, e.g., seeing their partner to be similar to them.

So assumed similarity and relationship outcomes are likely to influence each other in a mutual way.

In what situations might this assumed similarity not foster the conditions of initial attraction and better relational functioning?

This is really a hard scenario to think about. Most of the studies show that assumed similarity fosters initial attraction and better relationship function.

But if you think of assumed similarity as just one factor influencing relationship initiation and function, there might be some situations. Concerning relationship initiation, some factors, such as physical attractiveness and social resources, have an impact on initiation attraction besides assumed similarity. People need to make trade-off between these factors.

For example, if someone emphasizes more the physical attractiveness of a future partner, then even though she/he thinks the potential partner is similar to her/him in many ways but not that attractive in terms of physical features, it is likely that this person will not experience attraction toward the potential partner.

In established relationships, there are also many factors influencing better relationship functioning besides assumed similarity, such as relationship satisfaction, commitment level, and tactics of handling conflicts. If a relationship is full of bitterness and hardship, it is hard for assumed similarity to save such a relationship because you cannot ignore the reality when it is so obvious and repeated again and again in daily life.

Why do people tend to overestimate similarity in Honesty-Humility and Openness to Experience in people they share a close relationship with?

The reason why people assume higher similarity in Honesty-Humility and Openness to Experience with their close others is because these two personality traits have a strong correspondence to personal values.

There are two basic dimensions of personal values: Self-Transcendence versus Self-Enhancement and Openness to Change versus Conservation.

The former contrasts preferences for equality, honesty, loyalty, and social justice to preferences for authority, competence, social power, and wealth, and the latter contrasts preferences for creativity, curiosity, freedom, and novelty to preferences for obedience, security, social order, and tradition.

Honesty-Humility, characterized by sincerity, fairness, greed-avoidance, and modesty, is well-aligned with Self-Transcendence (vs. Self-Enhancement). Openness to Experience, characterized by aesthetic appreciation, inquisitiveness, creativity, and unconventionality, is well-aligned with Openness to Change (vs. Conservation).

Thus, these results suggest that the substantial levels of assumed similarity for these two personality traits can be understood in terms of the relevance of those dimensions to the domain of values. Values are an important part of people's social relationships: people tend to assume that their values are shared by those with whom they have close relationships and tend to develop relationships with those whose values are similar to their own.

In your opinion, what makes people that have lower relationship satisfaction less likely to view their partner as similar to them in honesty-humility and openness to experience?

Our study found that people with lower relationship satisfaction view their partner as less similar to them in Honesty-Humility and Openness to Experience.

As we pointed out before, Honesty-Humility comprises characteristics like being honest, trustworthy, kind, fair, and modest, and Openness to Experience comprises characteristics like being creative, unconventional, and open-minded.

All these traits are essential to make a good relationship. As these two personality traits are important to relationships, people in less satisfied relationships are less motivated to see these good points in their partner. Actually, there are studies showing that when people want to avoid intimacy, they tend to devalue their partner's care and interpret these caring behaviors as less voluntarily.

The research mentions how individuals often assume similarities in Honesty-Humility and Openness to Experience with their partner to help to solve the discrepancy between their ideal partner preference and actual partner choices. When can this kind of overcompensation become harmful?

Some studies have examined singles' ideal partner preference and found that singles prefer their ideal partner to be similar to them in personality traits, especially in Honesty-Humility and Openness to Experience.

However, studies examining established couples' personality found a quite different picture —couples do not really share similarity in these two traits in reality.

One strategy to solve the paradox that people want a similar partner but they cannot get such a partner in reality is to assume similarity in features that people want.

From literature examining assumed similarity and relationship quality, assumed similarity is typically positively related to relationship quality, which means that assumed similarity is usually beneficial to intimate relationships.

I think that over-assuming similarity in Honesty-Humility and Openness to Experience in relationship initiation is likely to be harmful. Even though it might facilitate relationship formation at first, the dissimilarity will gradually become salient as the relationship develops which is likely to risk relationship stability in the long run.

Do you have plans for follow-up research? Where would you like to see research on assumed similarity and relationship satisfaction go in the future?

If there is an opportunity, we are very happy to do a study to further examine the relationship between assumed similarity and relationship quality.

I would like to know the underlying mechanisms that could explain the relationship between assumed similarity in Honesty-Humility and Openness to Experience and relationship quality (i.e., satisfaction and commitment).

Also, I would like to know the dynamic and long-term effects of these variables. For example, it would be interesting to look at how assumed similarity in Honesty-Humility and Openness to Experience develops from relationship initiation and relationship maintenance, and how the relationship between assumed similarity and relationship quality develops over time.