Personality Similarity and Romantic Relationship Adjustment During the Couple Life Cycle

Abstract

Over the last decade, a substantial number of studies have focused on the role of personality traits and of the personality trait similarity/dissimilarity in partner selection and in predicting the quality of adult romantic relationships. The present study contributes to this general objective by investigating the correlations between levels of similarity/dissimilarity in partners’ personality profiles, analyzed through the Big Five dimensions, and levels of romantic relationship adjustment at different stage of a couple’s life course. A sample of Italian couples (N = 92 couples; 184 individuals) completed the Big Five Questionnaire and the Dyadic Adjustment Scale. The results revealed that similarity was not directly related with romantic relationship adjustment. Similarity only affected adjustment in interaction with the length of relationship. Partners reporting high levels of similarity in conscientiousness and openness showed the highest levels of romantic relationship adjustment during the first years of their relationship, while showing lower levels of adjustment as the relationship progressed. The lower levels of romantic relationship adjustment fell within the length of relationship range spanning between 10 and 21 years. These results suggest the importance of considering the life cycle perspective when studying the impact of personality similarity on romantic relationships, as well as suggesting the need to analyze the relationship between personality factors and interpersonal processes in a deeper way particularly in counseling and therapeutic contexts.

Keywords

couple relationship personality similarity romantic relationship adjustment life course

During the life course of a couple, romantic relationship adjustment is a continuous and changing process (Manyam & Junior, 2014). It can be conceptualized as the ability of the partners to solve problems (Madathil & Benshoff, 2008), to manage relational and daily developmental tasks (Spanier, 1976), and to accept different roles based on the changing developmental tasks of each stage of the family life cycle (Umberson, Williams, Powers, & Campbell, 2005). The literature on marital adjustment reveals a variety of factors that are related to each partner’s perception of the quality of the relationship in terms of consensus, satisfaction, cohesion and affective expression (Olson, 2011; Virginia, James, & David, 2000). According to these studies, personality and relational variables can either directly or indirectly affect dyadic adjustment. Couples’ relationships are, in fact, characterized by a complex interplay between interactions of the two partners and their respective intrapersonal characteristics (Lazaridès, Bélanger, & Sabourin, 2010). Couple research has often considered the key role of communication quality (e.g., Gottman, 1994; Gottman & Notarius, 2000), as well as cohesive and adaptive processes (D. H. Olson, 1993) of romantic relation adjustment; however, over the last decade, a substantial number of studies have focused on the role of personality traits in partner selection and in predicting the quality of adult romantic relationships (Gattis, Berns, Simpson, & Christensen, 2004; Gerris, Delsing, & Oud, 2010; Kilmann, 2012; Lou & Klohnen, 2005; Malouff, Thorsteinsson, Schutte, Bhullar, & Rooke, 2010; Robins, Caspi, & Moffit, 2000). These investigations have resulted in distinct lines of research, one of which focuses on the association between the relational satisfaction reported by each of the partners and their individual personality characteristics, while the other examines the links between similarities in personality traits and dyadic satisfaction (Luo & Klohnen, 2005; Malouff et al., 2010), with the latter being the line of enquiry that the present study pursues.

Most studies in this area used the five-factor model to assess the personality characteristics of the participants. This is due to the fact that the five dimensions hypothesized by this model (extroversion, agreeableness, conscientiousness, neuroticism, and openness) are core aspects of personality and are related to a variety of important life outcomes, including satisfaction in romantic relationships (Malouff et al., 2010).

Similarity in Partners’ Personality and Romantic Relationship Adjustment

We refer to similarity as the tendency for two individuals to be like each other at one moment in time. Research on partners’ similarities/dissimilarities has primarily focused on the topic of mate selection and relationship satisfaction. The key questions addressed were whether individuals tend to select similar or opposite partners with respect to their personality characteristics, behavior, and values, as well as whether partner’s similarity/dissimilarity with respect to behaviors, values, attitudes, and personality profiles affects couples’ relationships and correlates with romantic relationship adjustment (Decuyper, De Bolle, & De Fruyt, 2012).

The supposed similarity between romantic partners has been taken into account by sociologists through the homogeny theory (Berscheid, Dion, Walster, & Walster, 1971), by behavioral geneticists through the assortative mating theory (Buss, 1985), and by psychologists in terms of the attraction paradigm (Byrne, 1971). Each of these research traditions assumes that individuals tend to pair with intimate partners similar to themselves. These premises are supported by studies that revealed that the correlation between spouses with respect to variables such as age, religious affiliation, and level of education are consistently high (Bekkers, van Aken, & Denissen, 2006); however, there is no convincing empirical evidence for higher levels of personality similarity between romantic partners (Botwin, Buss, & Shackelford, 1997; Herbst, Gaertner, & Insko, 2003; Klohnen & Luo, 2003; Luo, 2009).

In particular, the comparison between the results of different studies have shown that the correlation between spouses with respect to variables such as age (.90 to .95), religious affiliation (.80 to .90), and level of education (.45 to .55) are consistently high (Bekkers et al., 2006). In contrast, the correlations between the scores obtained by the spouses in the personality dimensions, measured with instruments based on the Big Five model, are significantly lower. Botwin, Buss, and Shackelford (1997) found significant correlations ranging between .22 and .30 for agreeableness and conscientiousness and correlations between .38 and .51 for openness. Donnellan, Conger, and Bryant (2004) found positive relations between spousal reports of neuroticism (.16) and openness (.17) but not for the other dimensions. Other studies have found positive correlations among spouses with regard to neuroticism (.21), openness (.32), agreeableness (.23), and negative affect (.17; Watson, Klohnen, Casillas, Simms, & Haig, 2004). Van Aken, Denissen, and Bekkers (2006) found positive correlation with regard to agreeableness (.19) but no significant spousal correlations between levels of neuroticism (.02), conscientiousness (.08), and extroversion (.04).

In the last 10 years, different research has also tried to reveal if the level of partners’ similarity in personality traits affected the quality of their romantic relationships. This topic was analyzed from two empirical perspectives. The first, called the “similarity hypothesis,” postulates that attraction and romantic relationship adjustment are highest when the partners have similar levels for similar traits. The similarity–attraction effect (Byrne, 1971) is based on findings from social psychology in which people were more attracted to other individuals with similar personalities than to those with different personalities (Kausel & Slaughter, 2011).

The second perspective, called the “complementarity hypothesis” (Winch, Kstanes, & Kstanes, 1954), postulates that “opposites attract to complete and offset each other” (Kristof-Brown & Jansen, 2007, p. 131) and proposes that partners may be more satisfied when they differ on certain personality variables than when they match (Shiota & Levenson, 2007).

However, findings have revealed that the connection between similarity/complementarity in partners’ personality traits and dyadic satisfaction is still controversial (Orzeck & Lung, 2005). Some studies have found positive correlations between greater similarity among partners and levels of romantic relationship adjustment (e.g., Kurdek, 1993; Luo & Klohnen, 2005), others supported the complementarity hypothesis and revealed that adjustment was connected to different levels of specific traits personality (e.g., Shiota & Levenson, 2007), while others have found no significant connection between these two constructs (e.g., Gattis et al., 2004; Robins et al., 2000).

Among studies that have revealed positive correlations between partner’s greater personality similarity and levels of romantic relationship adjustment, Nemechek and Olson (1999) found that, while partners’ similarity on conscientiousness was related to greater marital adjustment for both spouses, partners’ similarity on neuroticism correlated significantly to marital adjustment for wives but not for husbands. In contrast, partners’ similarity on agreeableness correlated significantly with marital adjustment for husbands but not for wives. Decuyper, De Bolle, and De Fruyt (2012), in a study with 191 heterosexual couples, found that personality similarity was only significantly associated with relationship satisfaction in women. Luo and Klohnen (2005) revealed a lack of similarity between partners’ personality traits and a high similarity of attitudes and values. The authors also revealed that partners’ similarity in personality traits was a strong predictor of couple satisfaction. The same result was obtained in the studies by Gonzaga, Campos, and Bradbury (2007) and Gaunt (2006), which supported the hypothesis that similarity in personality traits is related to relationship quality for both men and women. Bekkers, van Aken, and Denissen (2006) also studied the connections between partners’ level of personality similarity, relationship duration, and well-being in the couple’s life. Although the study did not reveal significant personality similarity between romantic partners, its results seem to suggest that both individuals with high levels of neuroticism and openness, as well as couples whose partners had personality profiles that differ greatly from each other at the time of marriage, were more likely to experience marital problems. Finally, Kurdek (1993) found that higher discrepancy scores for neuroticism and conscientiousness characterized unstable couples and that large partner discrepancies on individual difference variables are risk factors for relationships.

These studies suggested that marital distress could arise from the failure of partners to resolve their personality differences and that well-adjusted couples tend to be similar on psychological characteristics (Kilmann, 2012).

In contrast to this perspective, some studies have not found that similarity/complementarity in partners’ personality was predictive of marital well-being (e.g., Robins et al., 2000; Watson et al., 2004).

Bleske-Rechek, Remker, and Baker (2009), for example, using relationship commitment as an index of relationship quality, found inconsistent evidence that dating couple personality similarity is associated with relationship quality. This is consistent with the results of Gattis, Berns, Simpson, and Christensen (2004), who considered the connections between six personality characteristics (e.g., Big Five personality factors and positive expressivity) and marital satisfaction in 132 distressed, treatment-seeking couples and 48 nondistressed couples. The authors found that higher neuroticism, lower agreeableness, lower conscientiousness, and less positive expressivity were tied to marital dissatisfaction, but their study did not show any direct association between partners’ similarity/dissimilarity in personality profiles and relational satisfaction.

The inconsistencies across above discussed studies could be attributable to the fact that some studies were based on heterogeneous samples with a wide variety of relationship lengths, while others were based on homogeneous samples of newlywed couples. Studies that analyzed relations between similarity/complementarity and couple relationships, in general, did not consider the age of the partners or the length of their relationship as moderators of the main effects of similarity (Shiota & Levenson, 2007).

Shiota and Levenson (2007) attempted to fill this gap by conducting a longitudinal study that examined the relationship between similarity in levels of the Big Five personality factors and marital satisfaction over a period of 12 years. Their sample, at the beginning of the study, was composed of midlife couples, couples whose partners were in their 40s years (with a minimum duration of marriage of 15 years), and long-term couples, couples whose partners were in their 60s (with a minimum duration of marriage of 30 years). The final sample for t1 (Time 0) and t2 (after 12 years) was composed of 27 middle-aged couples and 40 older couples. Partners completed measures at three different times over 12 years. Across the sample, greater overall personality similarity predicted more negative slopes in adjustment trajectories. In addition, spousal similarity on conscientiousness and extroversion more strongly predicted negative marital satisfaction outcomes among the midlife sample than among the older sample. Shiota and Levenson confirmed the complementarity hypothesis formulated by Winch (1958) and Kerckhoff and Davis (1962) and proposed theoretical arguments to explain the effects of personality dissimilarity on marital satisfaction over the life course, when partners are in their 20s, 40s, and 60s. They asserted that the life-course perspective can be a very useful tool to better understand the role of personality similarity/dissimilarity on couples’ relationships.

Similarity in Partners’ Personalities and Romantic Relationship Adjustment During the Life Course

Couples change in a number of ways over the life course. Partners must manage different life tasks at different times and what each spouse needs from the marriage is likely to change as a result. When partners are dating or are in the first stage of the couple relationship, the construction of a satisfactory bond and the development of intimacy are central (Murray, Holmes, & Griffin, 1996; Pasch & Bradbury, 1998). In this phase, called the phase of idealization, a positive global evaluation of the partner and of the couple relationship is associated with greater relationship satisfaction, even if this evaluation is based on a failure to acknowledge the partner’s true personality (Murray et al., 1996). Among young couples, during the first years of marriage, the development of a shared life, the definition of rules and roles, and the transition to parenthood are core issues (Murray et al., 1996; Pasch & Bradbury, 1998). Personality similarity may promote feelings of intimacy and attachment (Kurdek, 1991) and may help to increase a sense of equity in contributing to the marriage (Shiota & Levenson, 2007).

During the middle of life, which, for most couples, occurs 10–20 years into marriage (Shiota & Levenson, 2007), the increasing family and work life role demands, involving finances, parenting, the process of child individuation, household responsibilities, and responsibility in the workplace, among other things, can generate areas of conflict and strain (Moen, Kim, & Hofmeister, 2001). Midlife couples tend to disagree more than newer and older couples about finances and household responsibilities and about how to spend leisure time (Hatch & Bulcroft, 2004; Levenson, Carstensen, & Gottman, 1993). Some authors revealed that during the midlife period, personality similarity could become a disadvantage for partners (Shiota & Levenson, 2007). During this specific phase of the life cycle, one of the main developmental tasks for partners is the balancing of individual and shared responsibilities, and the increasing strain associated with this task could be managed more easily and effectively by partners with different personality traits, who can divide tasks, rather than competing with each other in similar performance domains (Moen et al., 2001).

After 25 or more years of marriage, many of the responsibilities so prevalent in midlife have diminished, and intimacy is again a core issue (Bouchard et al., 2005; Shiota & Levenson, 2007). The departure of children from the home and retirement from professional work increases the amount of time couples spend together. Partners, at this stage, are less conflictual, with less disagreement about parenting, household tasks, work–family balancing, and finances (Hatch & Bulcroft, 2004; Levenson et al., 1993), and tend to show more levels of positive emotional expressivity and more affectionate behavior during discussion or disagreement (Hatch & Bulcroft, 2004; Levenson et al., 1993). As such, at this stage, personality similarity may be less of a reason for conflict than in midlife (Shiota & Levenson, 2007).

Personality similarity could have different implications for marriages at each of these stages. Similarity might be helpful for dating couples and young marriages, enhancing the sense of intimacy, contributing to perceptions of balance and equity in the relationship, and making it easier to develop shared activities and goals (Kurdek, 1991; Murray et al., 1996; Pasch & Bradbury, 1998). It might also be useful for midlife couples to develop a common sense of agency in the management of their personal and relational developmental tasks (Moen et al., 2001). Similarly, it might be helpful for older couples to negotiate a new sense of intimacy and to share new aspects of their everyday life (Shiota & Levenson, 2007).

The Present Study

The relationships between partner similarity and romantic relationship adjustment have been explained by referring to two major theoretical positions: the similarity complementarity hypotheses. Up until now, few studies have attempted to verify these hypotheses, and the results from the studies available are controversial. Inconsistencies across studies’ results could be attributable to the use of heterogeneous samples with a wide variety of relationship lengths. Only a few studies have analyzed the specific link between couple similarity and relationship adjustment over time.

According to Shiota and Levenson (2007), focusing on the specific stage of the couple’s life course is central to understanding the connections between personality similarity and couples’ relationships. Considering these issues, and given the mixed findings revealed by discussed literature, the present study aimed to explore the relations between romantic partner relationship adjustment and partners’ personality similarity/dissimilarity profiles, analyzed through the Big Five dimensions, in different stages of the life course.

Method

Measures

Big Five Questionnaire (BFQ)

The BFQ (Caprara, Barbaranelli, & Borgogni, 1993) is a self-reporting questionnaire for assessing the Big Five personality dimensions of extroversion (α = .85), agreeableness (α = .85), conscientiousness (α = .85), emotional stability (neuroticism in the English version; α = .90), and openness (α = .88). It consists of 132 items, in the form of statements to which the subject must respond with a yes/no.

Dyadic Adjustment Scale (DAS)

The DAS (Gentili, Contreras, Cassaniti, & D’Arista, 2002; Spanier, 1976) is a self-reporting instrument made up of 32 items that measures the general adaptation of each partner within the romantic relationship and the subjective perception of the quality of the romantic relationship. The total score ranges from 0 to 151, with higher scores indicating more positive romantic relationships adjustment. The internal consistency of the romantic relationship adjustment total scale was α = .93.

Procedure and Participants

A convenience sample of 92 Italian heterosexual pairs living in Italy participated in this study. The criteria for inclusion were being aged 18 older and involvement in a romantic relationship of at least 6 months standing. Participants were recruited from attendants to a series of seminars on psychological topics conducted by the researchers involved in the research project. The seminars were aimed at psychology students, workers, teachers, counselors, and members of local nonprofit voluntary associations. Participation in the study was voluntary, and participants were told that the information provided would be anonymous and confidential and that only group data would be reported.

The researchers met couples in their homes and only met couples in which both partners had agreed to participate in the research. The tests were administered separately to each member of the couple during the same meeting. The couples were informed about the general objectives and procedures of the research project and detailed oral and written instructions were provided on how to complete the questionnaires. Written informed consent was obtained from all participants at the moment of assessment. The questionnaires were administered to 99 couples, but the questionnaires of 7 couples (7.07%) were excluded due to incomplete data.

The majority of pairs were married (71%), 14% were cohabiting but unmarried, and 15% reported being engaged in a stable relationship but not married or cohabiting. The duration of the couples’ relationships ranged from 0 to 35 years, with 36 couples who had been together between 0 and 9 years, 29 between 10 and 21 years, and 27 between 22 and 35 years. Of the pairs, 33% had one child, 56% had two, and 11% had three children. The oldest children of the couples in our sample were less than 10 years old in 35.4% of cases, between 11 and 21 years old in 36.2%, and between 22 and 34 years old for the remaining 28.3%. In the male subsample, the ages ranged from 19 to 62 years (M = 42.5, SD = 10.4), 94% were employed, 4% were students, and 2% were unemployed. In the female subsample, the ages ranged from 19 to 63 years (M = 39.3, SD = 10.25), 77% were employed, 15% were housewives, and 8% were students.

Data Analysis

We conducted univariate and bivariate analysis to examine distributional properties of the measures. Along the same lines as Humbad, Donnellan, Iacono, McGue, and Burt (2013), our approach to evaluating personality profile similarity is based on Cronbach and Gleser’s (1953) D-index. The D-index is a measure of geometric distance between vectors and considers differences in profile elevation and shape. The principal properties of the D-index are that it takes into account information on scatter, elevation, and shape of profile and that the lower bound is zero and the upper bound is infinity, so no limit is placed on the level of dissimilarity possible between two profiles. Finally, the D-index can be used in virtually any profile comparison situation (Chapman, 2007). In our study, we first obtained D-indices to quantify the agreement between personality profiles of each couple. We have considered the D-indices above the mean as “high,” and the D-indices lower than the mean as “low.” For each couple, we have also considered the mean of partners’ romantic relationship adjustment scores (Table 1). These steps have made it possible to treat the variable “couples with similar/different partners” as an independent variable and the variable “mean of romantic relationship adjustment partners’ scores” as a dependent variable.

Table 1.
Personality D-Indexes and Romantic Relationship Adjustment Scores: Descriptives.

D-indexes N Minimum Maximum M SD

D-index extroversion 92 .00 37.00 9.4457 6.84147

D-index agreeableness 92 .00 50.00 9.5000 8.17099

D-index conscientiousness 92 1.00 39.00 11.4891 8.61121

D-index emotional stability 92 .00 37.00 9.5326 7.63577

D-index openness 92 .00 34.00 9.6413 7.52784

Dyadic adjustment (couple mean) 92 66.00 141.00 114.5533 13.88725

Results

Our objective was to investigate the impact of partners’ personality similarity on romantic relationship adjustment. A univariate analysis of variance examined the main and interaction effects of personality similarity and length of relationship on romantic relationship adjustment. The analysis of variance results indicated two significant interaction effects (Table 2).

Table 2.
Univariate Analysis of Variance: Main and Interactions Effects of Personality Similarity and Length of Relationship on Romantic Relationship Adjustment.

Big Five Dimensions df Mean Squares F p

Extroversion Length of relationship 2 362.856 1.926 .149

Extroversion 1 258.393 1.372 .243

Length of Relationship × Extroversion 2 307.674 1.633 .198

Agreeableness Length of Relationship 2 446.931 2.396 .094

Agreeableness 1 249.823 1.339 .249

Length of Relationship × Agreeableness 2 445.633 2.389 .095

Conscientiousness Length of relationship 2 78.364 0.468 .627

Conscientiousness 1 487.759 2.910 .090

Length of Relationship × Coscientiousness 2 2,085.370 12.443 .000

Emotional stability Length of relationship 2 335.890 1.772 .173

Emotional stability 1 3.693 0.019 .889

Length of Relationship × Emotional Stability 2 301.042 1.588 .207

Openness Length of relationship 2 402.810 2.165 .118

Openness 1 101.263 0.544 .462

Length of Relationship × Openness 2 573.132 3.081 .048

Partners more similar with respect to conscientiousness, F(2, 2085) = 12.443, p < .001, showed the highest levels of romantic relationship adjustment during the first years of their relationship (M = 117.65, SD = 11.6), while they progressively showed lower levels of romantic relationship adjustment as the relationship progressed. The lower levels of romantic relationship adjustment were found in the length of relationship range between 10 and 21 years (M = 105, SD = 18.2); however, these levels then increase after 21 years in the relationship (M = 117.3, SD = 10.6). This trend is speculative for partners dissimilar with respect to conscientiousness. Partners less similar with respect to conscientiousness showed the lowest levels of romantic relationship adjustment during the first years of their relationship (M = 113.5, SD = 9.4), while they progressively showed higher levels of adjustment as the relationship progressed. The higher levels of romantic relationship adjustment were found in the length of relationship range between 10 and 21 years (M = 122.2, SD = 9.6) but were found to decrease after 21 years in the relationship (M = 114.2, SD = 14.5). Moreover, for openness similarity, F(2, 573) = 3.081, p < .05, we found a similar trend. The partners who reported more similar scores with respect to openness showed the highest levels of romantic relationship adjustment during the first years of their relationship (M = 117.21, SD = 9.4). They showed a progressive decrease in their levels of romantic relationship adjustment, which attained its lowest level when the relationship reached a duration between 11 and 21 years (M = 106.9, SD = 15.5), only to increase again after 21 years of marriage (M = 116.06, SD = 11.5). Partners less similar with respect to openness showed the lowest levels of romantic relationship adjustment during the first years of their relationship (M = 113. 6, SD = 12.9), while they progressively showed higher levels of adjustment as the relationship progressed. The higher levels of romantic relationship adjustment were found in the length of relationship range between 10 and 21 years (M = 115.3, SD = 13.7) but were found to decrease after 21 years in the relationship (M = 114.3, SD = 15.4; Figures 1 and 2). No significant effects of length of relationship and of personality similarity were found. No significant interaction effect between length of relationship and extroversion, agreeableness, and emotional stability was found (Table 2).

Figure 1.
Length of relationship and conscientiousness similarity on romantic relationship adjustment.

Figure 2.
Length of relationship and openness similarity on romantic relationship adjustment.

Discussion

This study aimed to examine, in a sample of Italian couples, the matching of partners’ personality within couples, in order to analyze associations between the partners’ similarity and their romantic relationship adjustment during different phases of the couple life cycle. Concerning the association between the personality similarity of the partners and romantic relationship adjustment, our results were congruent with previous research (e.g., Gattis et al., 2004; Robins et al., 2000) and revealed that similarity was not directly related with romantic relationship adjustment. Data revealed that similarity only affected adjustment in interaction with the length of relationship. Partners reporting high levels of similarity in conscientiousness and openness showed the highest levels of romantic relationship adjustment during the first years of their relationship, while showing decreasing levels of romantic relationship adjustment as the relationship progressed. The lower levels of romantic relationship adjustment fell within the range spanning between 10 and 21 years; however, these levels then increased after 21 years. In summary, it seems that there exist specific relational processes that are activated in coping with life’s developmental tasks, by mediating the effect of personality similarity in romantic relationship adjustment.

These results are in contrast with the “birds of a feather” dogma, according to which those with similar personalities “should stick together.” Our results suggest that people with too similar personalities may face increasing difficulty in living together in specific phases of the life cycle. In our sample, similarities in conscientiousness and openness are related to lower levels of romantic relationship adjustment, in particular in middle-aged couples. These findings are similar to the results of Shiota and Levenson (2007) who found an association between partners’ similarity in extroversion and conscientiousness and lower levels of marital satisfaction in middle-aged couples, but not in older couples.

In agreement with recent research (e.g., Bekkers et al., 2006; Dyrenforth, Kashy, Donnellan, & Lucas, 2010; Gattis et al., 2004; Shiota & Levenson, 2007), these results suggest that, in specific phases of the couple’s life cycle, it may be more important to differ in personality traits in order to achieve good dyadic adaptation. Among young couples, partner selection, the creation of emotional intimacy, the definition of common rules, and the development of a shared relational point of view are core issues (Klohnen & Luo, 2003). Personality similarity may promote feelings of intimacy and attachment and may help to increase feelings of being understood in a relationship and relationship satisfaction (Gattis et al., 2004). The increasing role demands typical of middle life, which involve finances, parenting, the process of child individuation, and household responsibilities, among other things, can generate areas of conflict and strain (Gonzaga, Campos, & Bradbury, 2007; Manyam & Junior, 2014; Moen et al., 2001). Some aspects of personality similarity in this phase may become a disadvantage (Shiota & Levenson, 2007). For instance, personality similarity may lead to difficulties in the care of adolescent and preadolescent children, when both partners have low levels of conscientiousness and, consequently, low levels of self-control, goal-oriented behavior, and thoughtfulness. In a couple in which the partners differ in this dimension, it may be easier to find a relational balance in which a partner who prefers planned and goal-oriented behavior takes care, for example, of the family rules, while the other partner, who is more oriented toward spontaneous behavior, may get more involved in providing emotional closeness to the children, especially in difficult moments.

In more mature relationships, life events such as the departure of children from the home and retirement from professional work can increase the amount of time that partners spend together. At this stage, personality similarity may be less of a reason for conflict than in midlife, and it could help partners to feel closer emotionally and to cope with new developmental tasks, such as the birth of nieces.

Limitations and Future Research Directions

It is necessary to point out some limitations in our study, which does not allow generalization of the results. First, our data were collected from an opportunity sample in a nonclinical setting, so the results may not apply to clinical populations. We are currently trying to address this limitation by investigating the associations among the same variables in a new sample of couples who have sought a therapeutic intervention to relational problems.

A further limitation of this study stems from having used only self-report instruments to detect the variables of interest. Future research should also consider the use of qualitative methodologies (e.g., in-depth interviews) in order to overcome the single-method biases and some of the major limitations of the self-report methodology. Future research that focuses on couples could involve both partners and use dyadic data analyses to assess the role of personality similarity on romantic relationship adjustment.

Furthermore, the research has a cross-sectional and correlational design with a simultaneous assessment of personality and some aspects of the quality of relationship. Naturally, this does not make it possible for us to establish any causal link between these variables. This limitation may be overcome in future research by using longitudinal studies that analyze relations between similarity and adjustment in a sample of couples across their life stages.

The effects of personality similarity on romantic relation adjustment, finally, could be influenced by a number of different mediators or moderators. The nature of our results, for example, could be mediated or moderated by specific cultural and social factors, such as attitudes, personal values, interests, belonging within the family or outside the family (e.g., Bekkers et al., 2006; Botwin et al., 1997; Herbst et al., 2003; Klohnen & Luo, 2003), and the style of attachment (e.g., Scharfe & Bartholomew, 1994; Luo & Klohnen, 2005). Considering these moderators may lead to a more nuanced understanding of when and why marriage succeeds or fails (Shiota & Levenson, 2007). These issues will be explored in future research.

Implications for Marriage and Family Counseling

The limitations highlighted make it rather difficult to produce final and conclusive interpretations; however, we think that the present findings have some clinical implications. Although our results are based on a nonclinical sample, some applicative implications can be still derived from them. The present study revealed lower levels of romantic relationships adjustment in middle-age couples who have similar personality traits. As these results suggest, a preliminary assessment of partners’ personalities could help in better identifying specific maladaptive interactive patterns. The information arising from such a screening could facilitate individual, couple, or relational counseling or therapy in several ways. This information could enable counselors and clinicians to match the type of intervention to the partners’ personality styles.

This finding can also suggest a need for analyzing the relation between personality factors and interpersonal processes in a deeper way in counseling and therapeutic contexts. Counseling and clinical work could be focused on specific ways in which matching of partners’ personality styles within dyads can influence decision-making processes, conflict management, and relationships with parents and sibling, among other things. Interventions could be directed to help partners to recognize their own and their partner’s personality traits, to play a specific role in alleviating their distress, to increase the partners’ capability to manage aspects of similarity or difference that create discomfort and suffering, and to tolerate anxiety generated by the relational difficulties.

Our data finally revealed that the influence of personality variables on marital adjustment may be different across changing life stages, highlighting the need for clinicians to reflect on the impact of personality similarity on romantic relationships adjustment during the life cycle, in order to better understand the interpersonal processes that lead to marriages improving or deteriorating over time (Bradbury, Fincham, & Beach, 2000; Gottman, 1993; Karney & Bradbury, 1995).

Compliance With Ethical Standards

In conducting the present research, ethical guidelines were followed. All procedures performed were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Participation in the study was voluntary, and the information provided was anonymous and confidential. Written informed consent was obtained from all participants prior to participation in the study.

D-indexes	N	Minimum	Maximum	M	SD
D-index extroversion	92	.00	37.00	9.4457	6.84147
D-index agreeableness	92	.00	50.00	9.5000	8.17099
D-index conscientiousness	92	1.00	39.00	11.4891	8.61121
D-index emotional stability	92	.00	37.00	9.5326	7.63577
D-index openness	92	.00	34.00	9.6413	7.52784
Dyadic adjustment (couple mean)	92	66.00	141.00	114.5533	13.88725

Big Five Dimensions	df	Mean Squares	F	p
Extroversion	Length of relationship	2	362.856	1.926	.149
Extroversion	1	258.393	1.372	.243
Length of Relationship × Extroversion	2	307.674	1.633	.198
Agreeableness	Length of Relationship	2	446.931	2.396	.094
Agreeableness	1	249.823	1.339	.249
Length of Relationship × Agreeableness	2	445.633	2.389	.095
Conscientiousness	Length of relationship	2	78.364	0.468	.627
Conscientiousness	1	487.759	2.910	.090
Length of Relationship × Coscientiousness	2	2,085.370	12.443	.000
Emotional stability	Length of relationship	2	335.890	1.772	.173
Emotional stability	1	3.693	0.019	.889
Length of Relationship × Emotional Stability	2	301.042	1.588	.207
Openness	Length of relationship	2	402.810	2.165	.118
Openness	1	101.263	0.544	.462
Length of Relationship × Openness	2	573.132	3.081	.048

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Bekkers

van Aken

M. A. G.

Denissen

(2006, 06 8). Social structure and personality assortment among married couples. Paper presented at the Dag van de Sociologie, Tilburg University, the Netherlands.

Berscheid

Dion

Walster

W. G.

(1971). Physical attractiveness and dating choice: A test of the matching hypothesis. Journal of Experimental Social Psychology, 7, 173–189. doi:10.1016/0022-1031(71)90065-5

Bleske-Rechek

Remker

M. W.

Baker

J. P.

(2009). Similar from the start: Assortment in young adult dating couples and its link to relationship stability over time. Individual Differences Research, 7, 142–158.

Botwin

M. D.

Buss

D. M.

Shackelford

T. K.

(1997). Personality and mate preferences: Five factors in mate selection and marital satisfaction. Journal of Personality, 65, 107–136. doi:10.1111/j.1467-6494.1997.tb00531.x

Bradbury

Fincham

Beach

(2000). Research on the nature and determinants of marital satisfaction: A decade in review. Journal of Marriage and the Family, 62, 964–980. doi:10.2307/353567

Buss

D. M.

(1985). Human mate selection: Opposites are sometimes said to attract, but in fact, we are likely to marry someone who is similar to us in almost every variable. American Scientist, 73, 47–51.

Byrne

(1971). The attraction paradigm. New York, NY: Academic Press.

Caprara

G. V.

Barbaranelli

Borgogni

(1993). BFQ: Big five questionnaire. Manual. Florence, Italy: O.S. Organizzazioni Speciali.

Chapman

(2007). Methods of examining agreement between profiles of continuous responses. Presentation made to the Psychiatry Interest Group in the Department of Biostatistics. Retrieved from https://www.urmc.rochester.edu

10.

Cronbach

L. J.

Gleser

G. C.

(1953). Assessing similarity between profiles. Psychological Bulletin, 50, 456–473. doi:10.1037/h0057173

11.

Decuyper

De Bolle

De Fruyt

(2012). Personality similarity, perceptual accuracy, and relationship satisfaction in dating and married couples. Personal Relationships, 19, 128–145. doi:10.1111/j.1475-6811.2010.01344.x

12.

Donnellan

M. B.

Conger

R. D.

Bryant

C. M.

(2004). The Big Five and enduring marriages. Journal of Research in Personality, 38, 481–504. doi:10.1016/j.jrp.2004.01.001

13.

Dyrenforth

P. S.

Kashy

D. A.

Donnellan

M. B.

Lucas

R. E.

(2010). Predicting relationship and life satisfaction from personality in nationally representative samples from three countries: The relative importance of actor, partner, and similarity effects. Journal of Personality and Social Psychology, 99, 690–702. doi:10.1037/a0020385

14.

Gattis

K. S.

Berns

Simpson

L. E.

Christensen

(2004). Birds of a feather or strange birds? Ties among personality dimensions, similarity, and marital quality. Journal of Family Psychology, 18, 564–574. doi:10.1037/0893-3200.18.4.564

15.

Gaunt

(2006). Couple similarity and marital satisfaction: Are similar spouses happier? Journal of Personality, 74, 1401–1420. doi:10.1111/j.1467-6494.2006.00414.x

16.

Gentili

Contreras

Cassaniti

D’Arista

(2002). La Dyadic adjustment scale. Una misura dell’adattamento di coppia. Minerva Psichiatrica, 43, 107–116.

17.

Gerris

J. R. M.

Delsing

M. J. M. H.

Oud

J. H. L.

(2010). Five personality factors and interpersonal trust in established marriages. Family Science, 1, 48–62. doi:10.1080/19424620903424094

18.

Gonzaga

G. C.

Campos

Bradbury

(2007). Similarity, convergence, and relationship satisfaction in dating and married couples. Journal of Personality and Social Psychology, 93, 34–48. doi:10.1037/0022-3514.93.1.34

19.

Gottman

J. M.

(1993). The roles of conflict engagement, escalation or avoidance in marital interaction: A longitudinal view of five types of couples. Journal of Consulting and Clinical Psychology, 61, 6–15.

20.

Gottman

J. M.

(1994). What predicts divorce? Hillsdale, NJ: Lawrence Erlbaum.

21.

Gottman

J. M.

Notarius

C. I.

(2000). Decade review: Observing marital interaction. Journal of Marriage and the Family, 62, 927–947. doi:10.1111/j.1741-3737.2000.00927.x

22.

Hatch

L. R.

Bulcroft

(2004). Does long-term marriage bring less frequent disagreements? Five explanatory frameworks. Journal of Family Issues, 25, 465–495. doi:10.1177/0192513X03257766

23.

Herbst

K. C.

Gaertner

Insko

C. A.

(2003). My head says “yes,” but my heart says “no”: Cognitive and affective attraction as a function of similarity to the ideal self. Journal of Personality and Social Psychology, 84, 1206–1219. doi:10.1037/0022-3514.84.6.1206

24.

Humbad

M. N.

Donnellan

M. B.

Iacono

W. G.

McGue

Burt

S. A.

(2013). Quantifying the association between personality similarity and marital adjustment using profile correlations: A cautionary tale. Journal of Research in Personality, 47, 97–106. doi:10.1016/j.jrp.2012.09.007

25.

Karney

B. R.

Bradbury

T. N.

(1995). The longitudinal course of marital quality and stability: A review of theory, method, and research. Psychological Bulletin, 118, 3–34. doi:10.1037/0033-2909.118.1.3

26.

Kausel

E. E.

Slaughter

J. E.

(2011). Narrow personality traits and organizational attraction: Evidence for the complementary hypothesis. Organizational Behaviour and Human Decision Processes, 114, 3–14. doi:10.1016/j.obhdp.2010.08.002

27.

Kerckhoff

A. C.

Davis

K. E.

(1962). Value consensus and need complementarity in mate selection. American Social Review, 27, 295–303. doi:10.2307/2089791

28.

Kilmann

P. R.

(2012). Personality and interpersonal characteristics within distressed marriages. The Family Journal: Counseling and Therapy for Couples and Families, 20, 131–139. doi:10.1177/1066480712439532

29.

Klohnen

E. C.

Luo

(2003). Interpersonal attraction and personality: What is attractive: Self similarity, ideal similarity, complementarity, or attachment security? Journal of Personality and Social Psychology, 85, 706–722. doi:10.1037/0022-3514.85.4.709

30.

Kristof-Brown

A. L.

Jansen

K. J.

(2007). Issues of person-organization fit. In Ostroff

Judge

(Eds.), Perspectives on organizational fit (pp. 123–154). New York, NY: Lawrence Erlbaum.

31.

Kurdek

L. A.

(1991). Predictors of increases in marital distress in newlywed couples: A 3-year prospective longitudinal study. Developmental Psychology, 27(4): 627–636. doi: 0.1037/0012-1649.27.4.627

32.

Kurdek

L. A.

(1993). Predicting marital dissolution: A 5-year prospective longitudinal study of newlywed couples. Journal of Personality and Social Psychology, 64, 221–242. doi:10.1037/0022-3514.64.2.221

33.

Lazaridès

Bélanger

Sabourin

(2010). Personality as moderator of the relationship between communication and couple stability. Europe’s Journal of Psychology, 2, 11–31.

34.

Levenson

R. W.

Carstensen

L. L.

Gottman

J. M.

(1993). Long-term marriage: Age, gender and satisfaction. Psychology and Aging, 8, 301–313. doi:10.1037/0882-7974.8.2.301

35.

Luo

(2009). Partner selection and relationship satisfaction in early dating couples: The role of couple similarity. Personality and Individual Differences, 47, 133–138. doi:10.1016/j.paid.2009.02.012

36.

Luo

Klohnen

E. C.

(2005). Assortative mating and marital quality in newlyweds: A couple centered approach. Journal of Personality and Social Psychology, 88, 304–326. doi:10.1037/0022-3514.88.2.304

37.

Madathil

Benshoff

J. M.

(2008). Importance of marital characteristics and marital satisfaction: A comparison of Asian Indians in arranged marriages and Americans in marriages of choice. The Family Journal, 16, 222–230. doi:10.1177/1066480708317504

38.

Malouff

J. M.

Thorsteinsson

E. B.

Schutte

N. S.

Bhullar

Rooke

S. E.

(2010). The five-factor model of personality and relationship satisfaction of intimate partners: A meta-analysis. Journal of Research in Personality, 44, 124–127. doi:10.1016/j.jrp.2009.09.004

39.

Manyam

S. B.

Junior

V. Y.

(2014). Marital adjustment trend in Asian Indian families. Journal of Couple & Relationship Therapy, 13, 114–132. doi:10.1080/15332691.2013.852491

40.

Moen

Kim

J. E.

Hofmeister

(2001). Couples’ work/retirement transitions, gender, and marital equality. Social Psychology Quarterly, 64, 55–71. doi:10.2307/3090150

41.

Murray

S. L.

Holmes

J. G.

Griffin

(1996). The benefits of positive illusions: Idealization and the construction of satisfaction in close relationships. Journal of Personality and Social Psychology, 70, 79–98. doi:10.1037/0022-3514.70.1.79

42.

Nemechek

Olson

K. R.

(1999). Five-factor personality similarity and marital adjustment. Social Behavior & Personality, 27, 309–318. doi:10.2224/sbp.1999.27.3.309

43.

Olson

(2011). Faces IV and the circumplex model: Validation study. Journal of Marital and Family Therapy, 37, 64–80. doi:10.1111/j.1752-0606.2009.00175.x

44.

Olson

D. H.

(1993). Circumplex model of marital and family systems: Assessing family functioning. In Walsh

(Ed.), Normal family processes (2nd ed., pp. 104–137). New York, NY: Guilford Press.

45.

Orzeck

Lung

(2005). Big-five personality differences of cheaters and non-cheaters. Current Psychology, 24, 274–286. doi:10.1007/s12144-005-1028-3

46.

Pasch

L. A.

Bradbury

T. N.

(1998). Social support, conflict, and the development of marital dysfunction. Journal of Consulting and Clinical Psychology, 66, 219–230. doi:10.1037//0022-006X.66.2.219

47.

Robins

R. W.

Caspi

Moffitt

T. E.

(2000). Two personalities, one relationship: Both partners’ personality traits shape the quality of their relationship. Journal of Personality and Social Psychology, 79, 251–259. doi:10.1037//0022-3514.79.2.251

48.

Scharfe

Bartholomew

(1994). Reliability and stability of adult attachment patterns. Personal Relationships, 1, 23–43. doi:10.1111/j.1475-6811.1994.tb00053.x

49.

Shiota

M. N.

Levenson

R. W.

(2007). Birds of a feather don’t always fly farthest: Similarity in big five personality predicts more negative marital satisfaction trajectories in long-term marriages. Psychology and Aging, 22, 666–675. doi:10.1037/0882-7974.22.4.666

50.

Spanier

G. B.

(1976). Measuring dyadic adjustment: New scales for assessing the quality of marriage and similar dyad. Journal of Marriage and the Family, 38, 15–28. doi:10.2307/350547

51.

Umberson

D. K.

Williams

D. A.

Powers

M. D.

Campbell

A. M.

(2005). As good as it gets? A life course perspective on marital quality. Social Forces, 84, 493–511.

52.

Virginia

D. R.

James

C. M.

David

K. R.

(2000). Communication and division making styles, power base usage, and satisfaction in marital dyads. Journal of Marriage and the Family, 62, 120–141. doi:10.1080/01463379709370074

53.

Watson

Klohnen

E. C.

Casillas

Simms

E. N.

Haig

(2004). Match makers and deal breakers: Analyses of assortative mating in newlywed couples. Journal of Personality, 72, 1029–1069. doi:10.1111/j.0022-3506.2004.00289.x

54.

Winch

R. F.

(1958). Mate selection: A study in complementary needs. New York, NY: Harper & Row.

55.

Winch

R. F.

Kstanes

(1954). The theory of complementary needs in mate selection: An analytic and descriptive study. American Sociological Review, 19, 241–249. doi:10.2307/2087753