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Attribution License (To ascertain which combinations of traits enhance romantic relationships, two competing strands of literature have burgeoned (Geher & Kaufman, 2011). First, according to many researchers, similarities between partners, on a range of traits, fosters satisfaction in relationships (e.g., Gonzaga, Campos, & Bradbury, 2007). Second, as implied by self-expansion theory (Aron & Aron, 1996, 1997), differences between partners can evoke a sense of growth and excitement, increasing the longevity of relationships (Dryer & Horowitz, 1997). This paper, however, shows the benefits of these differences subside whenever individuals feel their life now seems divorced from their future identity.
The Benefits of Similarities
Many studies have shown that partners who are similar—or believe they are similar—in personality (Gonzaga et al., 2007; Luo & Klohnen, 2005), coping styles (Anderson, Keltner, & John, 2003), attitudes (Gaunt, 2006), and values (Gaunt, 2006) are not as susceptible to separation or divorce. To illustrate, actual or perceived similarities in openness to experience (Luo & Klohnen, 2005) and extraversion (Dyrenforth, Kashy, Donnellan, & Lucas, 2010) have been shown to coincide with relationship satisfaction. Likewise, similarities in the degree to which partners utilize humor, affection, and enthusiasm to solve problems tend to diminish marital conflict (Johnson et al., 2005; see also Melby, Ge, Conger, & Warner, 1995).
A variety of accounts can explain the benefits of similarities between partners. First, according to the notion of implicit egotism (Pelham, Carvallo, & Jones, 2005), people tend to overestimate the desirability of their idiosyncratic features, such as their name, birthdate, possessions, and initials (Nuttin, 1985), especially when their self-esteem is high (for a review, see Bosson, Swann, & Pennebaker, 2000). Consequently, they will tend to appreciate another person with similar features to themselves (Pelham et al., 2005). When partners value the qualities and characteristics of one another, they tend to feel more satisfied with their relationship (e.g., Luo, Hao, Guoan, Zhang, Zhaoyang, & Xu, 2008).
Likewise, people often overestimate the qualities of anyone they perceive as members of their social identity (for a discussion, see Long & Spears, 1997). Individuals tend to assume that people who are similar to themselves belong to their social identity (Jetten, Spears, & Postmes, 2004) and, therefore, seem more worthy and desirable.
Conversely, partners who are different from one another may pursue distinct, and even conflicting, goals and motives. Yet, people also tend to embrace the goals and motives of their partner or significant others (Shah, 2003). Consequently, when partners differ from one another, they will often experience a tension between their own goals and motives and the goals and motives of their partner—a tension that has been demonstrated to impede wellbeing (Emmons & King, 1988). These conflicting goals may not only evoke this tension but can also impede collaboration and trust (Shiota & Levenson, 2007) as well as compromise the capacity of these individuals to understand the emotional experience of one another (Anderson et al., 2003).
The Benefits of Differences
Several complications, however, challenge accounts that predict the similarities between partners are beneficial. First, relationship satisfaction could foster perceived similarities between partners rather than vice versa. When individuals experience strong feelings of love, they become more likely to recognize similarities between one another (e.g., Fletcher & Kerr, 2010).
Second, in some circumstances, differences rather than similarities between partners can improve relationships, consistent with the notion that opposites may attract and that complementary attributes may diminish conflict (Berscheid & Walster, 1969). Indeed, a variety of studies have confirmed the possibility that differences in personality and other attributes can be beneficial, curbing the incidence of conflict and separation (Berscheid & Walster 1969; Dryer & Horowitz, 1997; Jones, Bell, & Aronson, 1972; Shiota & Levenson, 2007).
Again, several accounts could explain the benefits of differences between partners. For example, when partners differ from each other, one person is often more dominant than is the other person, at least in specific domains. These individuals are not as inclined to clash in their attempts to establish dominance (Tiedens & Fragale, 2003). Consistent with this stance, called dominance complementarity (Tiedens & Fragale, 2003), people who differ in dominance are not as likely to experience discord or conflict (e.g., Dryer & Horowitz, 1997). Instead, each partner can assume a distinct role in the relationship (Locke & Sadler, 2007). In addition, partners who are different from one another can more readily distribute tasks effectively, also diminishing conflict (Shiota & Levenson, 2007).
Self-expansion theory, proposed by Aron and Aron (1996, 1997), can explain and assimilate many of these purported benefits of differences between partners. According to self-expansion theory, one of the core motives of individuals is to extend their capabilities, resources, identities, and perspectives, called self-expansion (Aron & Aron, 1996). When this motive to self-expand is fulfilled, individuals enjoy a range of positive emotions, including excitement and arousal (Graham, 2008).
One of the central tenets of self-expansion theory, however, is that relationships often fulfill this motive to self-expand (Aron, Norman, Aron, McKenna, & Heyman, 2000). In particular, individuals often integrate their partner into their self-concept (Aron, Aron, & Smollan, 1992). They feel, therefore, they have acquired the qualities and characteristics of their partner, fulfilling the need to self-expand (Aron, Aron, Tudor, & Nelson, 1991). Consistent with this notion, people do not as quickly recognize their own traits, such as introversion, if their partner exhibits a conflicting trait, such as extraversion (Aron et al., 1991).
Self-expansion theory, therefore, implies that individuals are more inclined to seek fulfilling relationships with people who differ from themselves (for evidence, see Aron, Steele, Kashdan, & Perez, 2006). That is, once individuals establish a relationship with someone who manifests a capability or quality they have not acquired, their need to self-expand is fulfilled. They experience a range of positive emotions (Graham, 2008). These emotions are ascribed to the relationship, increasing the likelihood of satisfaction rather than boredom, infidelity, and dissolution, as research confirms (Lewandowski & Ackerman, 2006).
Psychological Connectedness to the Future
Contrary to many studies, self-expansion theory implies that differences between partners can be beneficial. To reconcile this contradiction, researchers have begun to clarify the boundaries of self-expansion theory.
First, researchers have acknowledged that individuals are not always motivated to self-expand. For example, after people commit to a relationship, the motivation to self-expand seems to wane, and the benefit of differences between partners abates (Amodio & Showers, 2005).
Socio-emotional selectivity theory offers a more comprehensive insight into the circumstances that elicit or inhibit the motivation to self-expand (Carstensen, 1995, 2006; Carstensen, Isaacowitz, & Charles, 1999). According to this theory, at any time, individuals experience one of two conceptualizations of their identity. First, before a major transition, such as impending death, individuals tend to feel their identity is transient (Carstensen & Fredrickson, 1998). In this state, individuals are not especially motivated to accrue resources that could be helpful in the future, such as knowledge or skills, because they cannot be certain which of these resources may be beneficial at this time (Carstensen, 2006). Instead, they strive to satisfy more immediate needs, such as to seek pleasure rather than delay gratification. Second, during periods of stability, individuals tend to feel their identity is enduring. Consequently, they are more inspired to accrue resources (Carstensen, 2006), analogous to self-expansion.
Many studies have corroborated the tenets of socio-emotional selectivity theory. In particular, before major transitions, such as departure from college (Pruzan & Isaacowitz, 2006) or impending death (Carstensen & Fredrickson, 1998; Mather & Carstensen, 2003, 2005), individuals tend to shift their memory, attention, and appraisals to positive features of the environment (see also Fung & Carstensen, 2003). This bias can foster immediate pleasure but impede learning. As these insights imply, if people feel their identity may shift abruptly—sometimes called psychological disconnectedness to the future (Bartels & Rips, 2010; Bartels & Urminsky, 2011)—the motivation to self-expand should subside.
Motives Versus Capabilities
In addition, even when self-expansion motives are primed, some differences between partners may obstruct, rather than fulfill, these needs. Differences in capabilities and differences in motives may not confer the same effects. In this context, capabilities refer to the degree to which individuals are able to achieve various goals, such as improve relationships or seek power; in contrast, motives refer to the degree to which individuals would like to achieve these goals (Schönbrodt & Gerstenberg, 2012).
Although people may feel motivated to extend their capabilities, they are not as likely to feel motivated to extend their motives or values. After all, the motives and values of individuals govern the goals that individuals pursue (cf., Ferguson, 2008). People who embrace an array of motives and values, therefore, are more likely to pursue conflicting goals—a conflict that has been shown to impede wellbeing (Emmons & King, 1988) and evoke negative emotions. These negative emotions may then be projected onto the relationships (Aron et al., 2000). Consequently, individuals who do not share the same motives or values are not as likely to establish fulfilling relationships.
The Present Study
The aim of this study, therefore, is to establish similarities and differences between partners that promote relationship satisfaction. In addition, this study assesses the theory that an enduring, rather than transient, identity should affect whether perceived differences in partners coincide with relationship satisfaction. Specifically, consistent with self-expansion theory (Aron & Aron, 1997), perceived differences in capabilities but similarities in motives should be associated with relationship satisfaction. Furthermore, when people experience a sense of connection to the future (Bartels & Urminsky, 2011), tantamount to an enduring identity (Carstensen, 2006), perceived differences in capabilities should be especially likely to be associated with relationship satisfaction.
To explore these possibilities, participants were instructed to answer questions about their level of relationship satisfaction as well as their own motives and capabilities. In addition, they answered questions that assess the motives and capabilities of their partner. Finally, they completed a measure that gauges the degree to which they feel connected to their future identity, developed by Ersner-Hershfield, Garton, Ballard, Samanez-Larkin, and Knutson (2009).
Method
Participants and Procedure
The participants comprised 119 women and 33 men, aged 18 to 61, and recruited from Facebook and through snowballing. Potential respondents received a status update from the first author, inviting these individuals to complete a questionnaire that would demand between 10 and 15 minutes of their time. They were informed the study was designed to examine the characteristics that affect relationship satisfaction. Some Facebook friends of the first author spontaneously distributed this status update to their own Facebook friends. All participants were involved in an ongoing romantic relationship that had begun 3 or more months ago. Approximately 55% of the participants indicated they were dating, 20% indicated they were living with their partner but not engaged or married, and 25% were engaged or married. On average, relationships had lasted 5.47 years (SD = 6.90).
Participants accessed a web link that activated a page in which the aims of this study and the rights of participants were described. The subsequent pages presented a series of demographic questions as well as scales to gauge motives, capabilities, and connectedness to the future in this order.
Materials
Relationship satisfaction
To gauge the quality of relationships, participants completed the Relationship Assessment Scale, validated by Hendrick, Dicke, and Hendrick (1998), comprising 7 items. A sample item is “How well does your partner meet your needs.” The Cronbach’s alpha of this scale has been shown to approximate .86 (Coulter & Malouff, 2013; Hendrick et al., 1998) and generated a value of .85 in this study.
Psychological connectedness to the future
To assess the extent to which participants feel their identity is enduring over time, participants completed an index of future self-continuity (Ersner-Hershfield et al., 2009; Hershfield, Cohen, & Thompson, 2012). Seven pairs of circles are presented, each overlapping to various extents. For each pair, the first circle represents the identity—that is, the values, goals, roles, and interests—of individuals now, whereas the second circle represents their identity in ten years. Participants select the pair of circles that best reflects the extent to which they feel their identity now is similar and connected to their identity in ten years. Higher levels of similarity or overlap have been shown to predict the degree to which individuals are willing to sacrifice their immediate needs to accrue a larger gain in the future (e.g., Bartels & Rips, 2010; Ersner-Hershfield et al., 2009).
Measurement of motives
To assess the motives of participants and their partners, participants answered a series of eight questions twice. First, they indicated the degree to which they are motivated to fulfill four fundamental needs—power (e.g., “I like to have the final say”), achievement (e.g., “I like to produce work of high quality”), affiliation (e.g., “I like to make as many friends as possible”), and intimacy (e.g., “Finding a soul mate is important to me”)—each corresponding to two questions. Next, the questions were then presented again, except the first person pronouns were supplanted with my partner and the grammar was adapted accordingly, to enable participants to indicate the extent to which their partner is motivated to fulfill these needs. These items were distilled from a review, conducted by Schönbrodt and Gerstenberg (2012), that integrated four distinct measures of motives: the personal values questionnaire, the goal inventory, and the Mehrabian affiliation scale. For each of the four subscales, the two items that generated the highest loadings were distilled.
Measurement of capabilities
To assess the capabilities of participants and their partners, a series of 19 questions was administered twice. These 19 questions assess the 8 key competencies that are vital to work, as defined by Bartram (2005): leading and deciding, supporting and cooperating, interacting and presenting, analyzing and interpreting, creating and conceptualizing, organizing and executing, adapting and copying, and finally enterprising and performing. Sample items include “I am a good public speaker” and “I am able to adapt to change and ambiguity well.” Participants first rated the degree to which they demonstrate these competencies. Next, they answered the same questions to rate the competencies of their partner, except first pronouns were again replaced with my partner.
Results
To test the hypotheses, an index that quantifies differences in motives between partners and an index that quantifies differences in capabilities between partners were constructed. Specifically, to quantify the difference in motives between partners, the difference between these two individuals on each of the eight items that gauge motives was calculated. These disparities were then squared, summed, and subjected to a square root. These differences were squared to ensure that positive and negative difference do not nullify each other; the sum of these differences was subjected to a square root to ensure the final range was comparable to the original scale. Second, an analogous procedure was applied to quantify the differences in capabilities between partners. The correlation between differences in motives and differences in capabilities between partners was .53—not high enough to indicate undue multicollinearity.
Moderated regression analysis was conducted to ascertain whether psychological connectedness to the future moderates the association between differences in motives and relationship satisfaction as well as the association between differences in capabilities and relationship satisfaction. For this analysis, the criterion was relationship satisfaction, and the predictors were age, gender, differences in motives, differences in capabilities, psychological connectedness to the future as well as the interactions between these differences and psychological connectedness to the future. To create these interactions, the corresponding variables were centered and then multiplied together. Significant interactions reflect a moderation effect (Aiken & West, 1991).
Table 1 presents the standardized B values and t values that emerged from this analysis. Both differences in motives and differences in capabilities were negatively associated with relationship satisfaction, after controlling age, gender, and psychological connectedness to the future. Furthermore, the interaction between differences in capabilities and future connectedness was significant.
Table 1
Output That Emerged From the Analysis That Predicted Relationship Satisfaction
| Variables | Standardized B Coefficients | t value |
|---|---|---|
| Constant | 10.18*** | |
| Sex | .13 | 1.74 |
| Age | -.18 | -2.45* |
| Difference in Motives | -.24 | -2.82** |
| Difference in Capabilities | -.18 | -2.13* |
| Future Connectedness | .28 | 3.80*** |
| Difference in Motives x Future Connectedness | -.04 | -0.37 |
| Differences in Capabilities x Connectedness | -.20 | -2.06* |
*p < .05. **p < .01. ***p < .001.
Figure 1 depicts this relationship between differences in capabilities and relationship satisfaction at high and low levels of future connectedness. These equations were derived from the standardized B coefficients. As Figure 1 shows, differences in capabilities were inversely related to relationship satisfaction. Yet, as psychological connectedness to the future increased, this negative relationship became progressively less pronounced.
Figure 1
Schematic illustration of the interaction between differences in capabilities and future connectedness.
Discussion
Despite the array of studies that demonstrate the benefits of similarities between romantic partners (e.g., Gaunt, 2006; Gonzaga et al., 2007; Luo & Klohnen, 2005), self-expansion theory implies that differences between romantic partners can also foster satisfaction in relationships; indeed, past research has shown that differences between partners are positively associated with relationship satisfaction, at least in some circumstances (e.g., Shiota & Levenson, 2007). Two caveats, however, can be applied to reconcile this conflict.
First, when individuals feel their identity is transient and dislocated from their future, the motivation to self-expand should subside (Carstensen, 2006), and the benefits of perceived differences between partners should abate. Second, in contrast to perceived differences in capabilities, perceived differences in motives should be negatively, rather than positively, associated with this satisfaction in relationships. That is, perceived differences in motives between partners could evoke conflicting goals and, therefore, should not facilitate self-expansion. As hypothesized, perceived differences in motives between partners were inversely associated with relationships satisfaction. Perceived differences in capabilities between partners were also negatively related to relationship satisfaction, but especially when people reported a sense of dislocation or disconnection from their future identity.
Broadly, this pattern of results aligns to the tenets of self-expansion theory when buttressed with socio-emotional selectivity. In particular, according to the notion of socio-emotional selectivity, when people feel dislocated from their future (Bartels & Rips, 2010), and thus perceive their identity as transient, they are not as willing to sacrifice their pleasure now and invest in the future (Carstensen, 2006). They do not, therefore, value the accumulation of resources, such as knowledge or skills. Their self-expansion motives, thus, tend to subside. In this state, individuals are not as likely to appreciate capabilities they have yet to acquire. Consistent with this premise, in this study, when psychological connectedness to the future was limited, differences in capabilities were even less likely to foster satisfaction in relationships.
Yet, contrary to the hypotheses, even when participants reported a sense of connection to the future, perceived differences in capabilities were negatively associated with relationship satisfaction. That is, these findings diverge from the assumption that differences between partners can be beneficial, at least in some settings, as underscored by Aron et al. (2006).
Two sets of accounts could explain this finding that differences in capabilities did not foster satisfaction in relationships, even when participants experienced a sense of connection to the future. First, similarities in capabilities between partners may not fulfil the motivation to self-expand but, instead, generate a suite of other benefits. Like similarities in motives, similarities in capabilities could imply that individuals share an idiosyncratic feature in common (Pelham et al., 2005) or belong to an overlapping social identity (Jetten et al., 2004). Shared idiosyncratic features and social identities have been shown to translate into favorable evaluations (Long & Spears, 1997).
Second, differences in capabilities between partners may actually impede, rather than facilitate, self-expansion. That is, if capabilities diverge considerably between partners, each individual may become more attuned to their own shortcomings, called a contrast effect (Mussweiler, 2001). Because people, in general, tend to bias their attention more to problems than to benefits (see Baumeister, Bratslavsky, Finkenauer, & Vohs, 2001), this awareness of shortcomings could damage their self-efficacy. This sense of self-efficacy is the cornerstone of self-expansion (Aron & Aron, 1997). Differences in capabilities between partners, therefore, may compromise the self-efficacy of individuals, impeding self-expansion, evoking negative emotions (Graham, 2008), and thus compromising relationships (cf., Aron, Fisher, Mashek, Strong, Li, & Brown, 2005).
Several limitations may need to be resolved in future studies. First, differences in motives and capabilities were measured rather than manipulated, and hence the direction of causality was not established definitely. In future studies, these similarities and differences could be manipulated. For example, participants could be asked to transcribe two similarities and two differences between themselves and their partner. According to the concept called ease of retrieval (Ruder & Herbert, 2003), these two similarities or two differences should be readily accessible, promoting individuals to assume they share many other similarities or differences with their partner (Haddock, 2002). If various instances of some category are easy to retrieve—such as traits that two partners share—individuals tend to overestimate the frequency or validity of this category (Haddock, 2002; see also Tversky & Kahneman, 1973). Consequently, this manipulation should affect evaluations of relationship satisfaction and clarify the direction of this association.
An analogous procedure could be used to manipulate psychological connectedness to the future. Indeed, Bartels and Urminsky (2011) validated a similar procedure to manipulate this level of connectedness. In their study, participants were instructed to specify two or ten reasons to explain why their life would remain stable in the future. If asked to identify two rather than ten reasons their life may remain stable, participants were more inclined to sacrifice some money now to earn more money later, epitomizing psychological connectedness to the future.
Second, the measures could be improved as well. Specifically, relationship satisfaction was measured explicitly. Potentially, when relationships are fragile, participants may not feel confident enough to express their concerns, consequently inflating their level of reported satisfaction. Consistent with this possibility, feelings of distrust seem to be inversely associated with disclosure (e.g., Rios, Ybarra, & Sanchez-Burks, 2013). Therefore, people who claim to be satisfied with their relationships may actually experience dissatisfaction. This explicit measure of relationship satisfaction, therefore, may not be especially accurate.
To override this bias in future research, implicit measures may be needed to gauge relationship satisfaction. For example, the affective priming task could be suitable (e.g., Back et al., 2009). That is, if relationships are satisfying, subliminal photographs of their partner should subsequently improve their capacity to recognize positive words but not negative words. These implicit tasks override any defensive responses of participants and, therefore, may represent a more accurate assessment of relationship satisfaction.
Finally, the sample could be more representative of the broader population. The sample in this study was skewed towards women and couples who were dating rather than de facto or married. Because commitment can affect the determinants of satisfaction (Amodio & Showers, 2005), this bias should be redressed in future studies, perhaps by collecting a random sample of couples instead of a convenience or snowball sample.
In conclusion, this study indicates that individuals who feel their life now is pertinent to their identity in the future, called psychological connectedness to the future, may be more willing to withstand, or even embrace, some of the differences between themselves and their partner. Relationship counsellors, therefore, should perhaps cultivate the conditions that enable partners to feel this sense of connection to the future. Even simple exercises, such as inviting clients to write to their future identity (van Gelder, Hershfield, & Nordgren, 2013), or to imagine, as vividly as possible, their future aspirations as well as two or three main activities that need to be undertaken to achieve these goals, could diminish the resentment that differences between partners can evoke.