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The notion that people differ in their characteristic ways of dealing with the world is one of the most basic human intuitions. The ancient Greeks believed that the balance of bodily fluids (humors) determined a person’s basic character. Later theories linked to date of birth, skull shape, and body structure, but these ideas have failed to find empirical support.

A more solid and scientifically supported theory of personality emerged in the 1980s. According to The Big Five approach, human personality consists of five basic traits, each of which exists on a continuum between opposites. The mix of these five qualities in an individual predicts the person’s typical behavior in different situations and over time. The five major traits are:

Neuroticism— and volatility versus and ;

and volatility versus and ; — persistence and responsibility versus sloppiness and laziness;

persistence and responsibility versus sloppiness and laziness; — friendliness and versus hostility and insolence;

friendliness and versus hostility and insolence; — and curiosity versus intolerance and rigidity;

and curiosity versus intolerance and rigidity; Extroversion— and urgency versus and .

These traits are genetically based. They tend to crystallize in early adulthood and remain more or less stable thereafter. Personality is not the only factor shaping our destiny: Circumstances—situational, cultural, and historical—also have a lot to do with it, as do chance and anatomy, of course. Yet the influence of personality is evident in many realms of life, such as choice, health status, and lifestyle. Not surprisingly, the research literature also points to a significant predictive association between the Big Five personality traits and romantic life.

Here is a rough sketch of those findings.

Neuroticism

By a broad (and rare) scholarly consensus, neuroticism is the personality trait most strongly predictive of a person’s romantic destiny. High neuroticism is uniformly bad news in this context. For example, in 1987 University of Michigan researchers Lowell Kelly and James Connelly published a study that followed 300 married couples over 30 years. The neuroticism of one spouse predicted dissatisfaction in and . Adding insult to injury, research has also shown that high neuroticism predicts low resilience post-divorce.

Neuroticism appears to interfere with relationship satisfaction in multiple ways. By definition, neurotic individuals tend to be highly reactive to and prone to experiencing negative emotions. These tendencies are likely to radiate onto the partner and create problems over time.

Neuroticism also appears to interfere with healthy . Terri Fisher at Ohio State University and James McNulty Florida State University (2008) asked 72 newly-married couples about their character, relationships, and sexual satisfaction. A year later, the researchers returned to examine the quality of the relationships of couples. They found that neuroticism of one partner (or both) predicted lower levels of satisfaction in relationships and sex. Neuroticism, the researchers further found, tended to undermine marital quality by interfering with the couple's sex life. The authors contend that neuroticism dampens sexual satisfaction because neurotic individuals are prone to negative affect and expectations, which have been shown to relate to lower sexual arousal and satisfaction.

For those who wish for a bit of existential spice in their explanatory sauce, Jamie Goldenberg and colleagues argue that neuroticism may interfere with one’s sex life in part because “the creaturely aspects of sex make apparent our animal nature, which reminds us of our vulnerability and mortality.” Neurotics are uniquely ill-equipped to manage this reminder, and are thus driven to avoid or devalue sex.

Conscientiousness and Agreeableness

As might be expected, high levels of conscientiousness and agreeableness predict relationship satisfaction, in part because these traits signify low impulsivity and high interpersonal trust, respectively.

Personality psychologist Portia Dyrenforth and colleagues (2010) published a study of 20,000 couples in three countries—Australia, England, and Germany—finding that high agreeableness and conscientiousness (as well as low neuroticism) in self or spouse were associated with marital satisfaction. Low agreeableness and low conscientiousness have been found to specifically predict sexual . In a study of more than 16,000 participants from 52 countries, the researcher David Schmidt of Bradley University found that low levels of agreeableness and conscientiousness predicted .

Rick Hoyle and his colleagues at the University of Kentucky (2000) analyzed findings from 53 studies on the relationship between three types of personal risk-taking sex—casual sex with strangers; unprotected sex (without a condom); and having a large number of partners—and found that low agreeableness (which often manifests as high hostility) predicted all three behaviors. Further, low conscientiousness predicted involvement in unprotected sex.

Openness to Experience

Openness appears to play a rather minor role in the romantic context. In 2010, the Australian researcher John Malouff and his colleagues analyzed the results of 19 studies involving more than 3,800 participants. Four traits—low neuroticism, high conscientiousness, high agreeableness, and high —predicted higher levels of relationship satisfaction with intimate partners. Findings relating to openness were MIA.

Yet openness is not entirely inconsequential: Researchers Andrea Meltzer and James McNulty of Florida State University recently asked 278 pairs of newlyweds to keep a daily log of their sexual activities for two weeks. Respondents were also questioned about their personalities and the quality of their relationship. One of their findings was that the woman’s personality predicted the frequency of sexual relations in the marriage. Specifically, couples in which the woman scored high on the traits of agreeableness and (to a lesser extent) openness had sex more often. The husband’s personality had no effect on the frequency of sex, although more open (and neurotic) husbands were less sexually satisfied.

Because many studies have already shown that men tend to seek more frequent and varied sex than women, the researchers speculate that the woman is usually the “gatekeeper” for sex in the marriage, and determines if and how often it will happen.

Extroversion

Extroversion has been found to strongly predict several love- and sex-related outcomes. However, high extroversion appears to be somewhat of a double-edged sword in this context. Extroverts tend to be happier, more socially connected, and more charismatic than introverts. They seek relations and are skilled at handling them. They also tend to be better adjusted sexually.

On the other hand, high extroversion can undermine relationships because it is associated with adventurism. A 2008 study by David Schmidt involving more than 13,000 participants in 46 countries found high extroversion to be “positively correlated with interest in short-term , unrestricted sociosexuality, having engaged in short-term mate poaching attempts, having succumbed to short-term poaching attempts of others, and lacking relationship exclusivity.”

In a study of long-married couples, Arlene Rosowski of Harvard and colleagues found that high extroversion and low conscientiousness in men predicted lower marital satisfaction for their wives. Contrary to popular belief, couples do not become more similar in personality as they age together; rather, people tend to select partners who are quite like themselves. In fact, research has shown that people tend to pick partners who resemble them across multiple domains, a phenomenon known as assortative mating. Generally speaking, when it comes to , birds of a feather flock together.

Interestingly, this tendency can have profound effects on society. Wealthy people tend to marry other wealthy people. Highly educated people tend to marry other highly educated people. In a society like ours, where and high-paying jobs are available for both sexes, social gaps in income, status, and achievement are bound to grow fast, as the wealthy and highly educated increasingly mate with each other.

When it comes to personality, our knowledge of the human tendency to seek similarity in a mate raises the question: Does personality similarity between spouses predict happier marriage? The answer: Probably not.

Granted, some evidence exists that similarity predicts relationship satisfaction. Shanhong Luo (2009) followed 117 newly-dating couples and found that similarity in personality traits predicted higher relationship satisfaction.

However, the bulk of the evidence appears to show that similarity is not a strong predictor of relationship outcome. Portia Dyrenforth and colleagues found no relationship between the degree of similarity of the couple's personalities and satisfaction in marriage. In a recent study of more than 1600 couples, Swiss psychologist Katrin Furler and her colleagues found no relationship between personality similarity and life satisfaction.

It is possible that the meaning of personality similarity changes across the life of the relationship. Michelle Shiota of the University of Arizona and Robert Levenson at the University of California, Berkeley (2007) found that while similar personality predicts higher relationship satisfaction among young married couples, among older couples, similarity in the major traits predicted reduced satisfaction.

In Summary

Our basic personality traits are under strong genetic influence and are not easy to change. Personality predicts behavior in many areas, including relationships, sexual behavior, and satisfaction. High neuroticism is clearly problematic in this context. In contrast, agreeableness and conscientiousness are unambiguously positive qualities. Openness appears to play a minor role, and extroversion has a mixed-bag quality, with both positive and negative consequences for relationships. Contrary to popular belief, personality similarity between spouses is not necessary for long-term relationship success.

Overall, the data suggest that those who are looking for a partner for enduring love and sex need not fixate on finding someone similar to them in personality. Rather, they’d benefit from looking for a partner who’s agreeable, conscientious, and emotionally stable. An extroverted partner may prove a package deal: It’ll be fun, but it might not end well. An overly neurotic partner is an invitation to the blues.

Recognizing some of these character traits in yourself or your partner may make you for the long-term health and sexual of your relationship. But it’s useful to remember that a person may decide to change, improve their habits, and better manage their hardwired personality tendencies through self-awareness, practice, and a desire to have their conduct express the values they deem worthy. In the words of William Faulkner, a person can aspire to be better than himself. And what better incentive to change and better ourselves than love?