A well-functioning relationship is beneficial for a healthy and long-lasting life (Robles et al., 2014; Slatcher & Selcuk, 2017). At the same time, it is inevitable for couples to experience interactions such as conflict on daily issues or receiving undesirable criticism from their partners. These interactions might pose a threat to one’s positive self-image, which could result in defensive reactions towards each other (e.g., behaving badly, Murray et al., 2003) to protect and secure one’s self-image. We believe it is important to study variables potentially related to adaptive responses to self-threatening interactions in relationships to be able to keep relationships ‘healthy’. Based on self-affirmation theory (Cohen & Sherman, 2014; Steele, 1988), the process of self-affirmation (i.e., acts to maintain a positive self-image) might be such a variable that is related to more adaptive coping with these types of interactions (e.g., Jaremka et al., 2011). Although self-affirmation has mainly been induced experimentally (e.g., by asking people to think about important personal values or positive characteristics), recent studies suggest that it may also occur spontaneously among individuals (Harris et al., 2019). Spontaneous self-affirmation is suggested as a potential natural resource that could be used to cope with psychological threats (Harris et al., 2022); it might also have potential benefits in dealing with self-threats related to relationships. However, the association between spontaneous self-affirmation and relationship functioning has not been investigated yet. Therefore, in this study, we aim to investigate whether spontaneous self-affirmation is associated with indices of relationship functioning, namely, relationship satisfaction, intimacy, commitment, conflict frequency, and conflict resolution styles. Additionally, we aim to investigate whether the associations between spontaneous self-affirmation and these variables remain significant after controlling for two important, previously established, predictors of relationship functioning: attachment anxiety and avoidance (Joel et al., 2020; Mikulincer & Shaver, 2007).

Self-affirmation theory and relationship functioning

According to self-affirmation theory (Steele, 1988), people have the motivation to maintain self-integrity, a self-image that is ‘morally and adaptively adequate’ (Sherman & Cohen, 2006, p. 187), and interactions that threaten self-integrity drive them to re-establish it. Likewise, self-threatening interactions in relationships might drive couples to respond defensively to protect their self-integrity, which might be detrimental to a well-functioning relationship. For instance, individuals might defensively distance themselves from their partners in response to self-threats in a relationship (Jaremka et al., 2011). However, according to the theory, engaging in self-affirmation (i.e., acts that establish one’s self-adequacy; Cohen & Sherman, 2014) provides people with a state of mind that makes the threat more manageable and makes people react more adaptively to self-threats. This, in turn, could favor self-affirmed individuals and their relationships by responding to threatening information in a less self-defensive way. For instance, self-affirmation decreases destructive behavioral intentions (e.g., acting selfishly and ignoring the partner’s feelings) of low self-esteem individuals in self-threatening relationship situations (Jaremka et al., 2011).

Self-affirmation has mainly been induced experimentally by asking participants to reflect on core values (e.g., Jaremka et al., 2011) and previous research confirmed the positive effects of self-affirmation inductions on close relationships. More specifically, these studies indicated that self-affirmation resulted in more positive other-directed feelings (e.g., love or gratefulness; Crocker et al., 2008), more comprehensive apologies, and less defensive strategies (e.g., blaming the victim; Schumann, 2014), increased relational security and social behaviors of insecure individuals (Stinson et al., 2011) and less destructive responses (e.g., communal disinvestment into partner’s well-being) of low self-esteem individuals to relationship-based threats (Jaremka et al., 2011). Moreover, Schumann et al. (2021) applied an adapted version of a self-affirmation manipulation (big-picture affirmation) among couples and found that this kind of affirmation, but not a standard self-affirmation, has long-lasting positive effects on romantic relationships such as increased constructive responses to conflicting situations.

Spontaneous self-affirmation and relationship functioning

Importantly, it has been suggested that self-affirmation can also occur spontaneously in response to psychological threats and that there are differences in the extent to which individuals spontaneously self-affirm (Harris et al., 2019). In other words, individuals can self-affirm naturally and unforcedly by thinking about their strengths, social relations, or values in the face of everyday threats (Harris et al., 2019). Although research on spontaneous self-affirmation is relatively new, evidence suggests that spontaneous self-affirmation is related to favorable outcomes such as approach coping (Sharouni et al., 2022), greater positive affect (Sharouni et al., 2022; Taber et al., 2016), and indices of mental health and well-being (Emanuel et al., 2018; Harris et al., 2022; Jessop et al., 2022; Sharouni et al., 2022). For example, Jessop et al. (2022) investigated the association of spontaneous self-affirmation to well-being in three studies and found that it consistently predicted hedonic and eudaemonic well-being outcomes such as flourishing, affect balance, need satisfaction, and anxiety. In sum, accumulating evidence suggests that higher levels of spontaneous self-affirmation are related to beneficial outcomes in many aspects.

Taking this into consideration, it could also be expected that similar positive associations could emerge in people’s romantic relationships. Namely, individuals who spontaneously self-affirm might respond more adaptively to relationship threats and therefore have a better functioning relationship compared to those who less spontaneously self-affirm. Even though there is no agreement on what makes a relationship well-functioning and how to measure it (Vitek & Yeater, 2021), higher satisfaction, intimacy, commitment, lower conflict frequency, and more constructive and less destructive conflict resolution styles are widely used as indicators of relationship functioning (e.g., Mikulincer & Shaver, 2007; Vitek & Yeater, 2021). Therefore, in this study, we tested the prediction that higher levels of spontaneous self-affirmation would be associated with increased relationship satisfaction (H1a), intimacy (H1b), and commitment (H1c), and a decreased conflict frequency (H1d) in relationships. Moreover, individuals with higher levels of spontaneous self-affirmation were expected to use more constructive (i.e., positive problem solving; H1e) and less destructive (i.e., conflict engagement, withdrawal, and compliance; H1f) resolution styles in response to conflicting interactions.

Spontaneous self-affirmation, attachment dimensions, and relationship functioning

Hazan and Shaver (1987) conceptualized romantic love as an attachment to the partner and proposed three adult attachment styles: secure, avoidant, and anxious/ambivalent. Subsequent researchers (e.g., Fraley et al., 2000) have proposed anxiety and avoidance as two primary dimensions underlying adult attachment, and since then, this two-dimensional framework has been widely accepted and commonly used in attachment studies. Attachment anxiety is characterized by fear of rejection and abandonment, unsatisfied need for closeness, and heightened preoccupation with the relationship (Mikulincer & Shaver, 2007). Attachment avoidance is characterized by the reluctance to establish intimacy and emotional connectedness in relationships. Attachment security is defined by lower levels on both attachment dimensions. Besides, one distinguishing feature of attachment anxiety is the individual’s negative self-representations (e.g., I am unworthy), while the negative images of others (e.g., they cannot be trusted) are associated with attachment avoidance (Mikulincer & Shaver, 2007). Conversely, positive self-representations and positive views of others are defining characteristics of attachment security. As positive self-image and relationships with others (i.e., family or friends) are considered resources for self-affirmation (Cohen et al., 2000), attachment security (i.e., low anxiety and avoidance) is expected to be associated with having more resources for spontaneous self-affirmation. In other words, people with negative representations of themselves (i.e., attachment anxiety) or others (i.e., attachment avoidance) might have difficulty to spontaneousely self-affirm. Besides, engaging in spontaneous self-affirmation might increase one’s relational security over time by reminding positive aspects of self and relationship with others (see also, Stinson et al., 2011). Therefore, in this study, we anticipate negative associations between spontaneous self-affirmation and attachment anxiety (H2a) and avoidance (H2b). Additionally, attachment anxiety and avoidance are two well-documented predictors of relationship functioning (Joel et al., 2020; Mikulincer & Shaver, 2007). Thus, the anticipated shared variance between attachment dimensions and spontaneous self-affirmation could potentially be responsible for an association between spontaneous self-affirmation and relationship functioning. As a research question, we will therefore investigate whether spontaneous self-affirmation is uniquely associated with the indices of relationship functioning over and above attachment anxiety and avoidance (RQ1).

The current study

In the present study, we are mainly interested in testing if there is an association between spontaneous self-affirmation and relationship functioning as conceptualized by increased satisfaction, commitment, and intimacy, decreased conflict frequency, and engagement in more constructive and less destructive conflict resolution styles. Given the positive effects of experimentally induced self-affirmation on relationships, we hypothesized that the tendency to spontaneously self-affirm would be related to improved relationship functioning (H1a to H1f). Furthermore, based on our theoretical framework, we expected negative associations between spontaneous self-affirmation and attachment anxiety (H2a) and avoidance (H2b); two established predictors of relationship functioning. Finally, as a research question, we aimed to explore the unique variance between spontaneous self-affirmation and relationship functioning after controlling for its overlap with attachment anxiety and avoidance (RQ1). To test our predictions and answer our research question, we conducted a pre-registered online studyFootnote 1 (see https://osf.io/f4sjw) among individuals who have a romantic relationship partner with whom they have been living together for at least one year.

Method

Participants

Being 18 years or older, having a romantic relationship and living with their partner for at least one year were the inclusion criteria of this study. To determine the required minimum sample size, we applied a power analysis via G-Power (Faul et al., 2007). As this is the first study investigating the association between spontaneous self-affirmation and relationship functioning, we did not have a direct prediction about the effect size of this association. On the other hand, studies (e.g. Emanuel et al., 2018) investigating the association of spontaneous self-affirmation to individual well-being, an important correlate of relationship functioning (Gere & Schimmack, 2013), demonstrated a small to medium effect size. Based on these studies, we predicted a small to medium effect size and the results of power analysis indicated that a minimum of 188 participants are needed (f2 set to 0.07, α to 0.006, power to 0.80, and number of predictors to 5; the α-level takes multiple testing into account; number of predictors takes demographic controls into account). We conducted an additional power analysis for our research question (i.e., Does spontaneous self-affirmation predict the indices of relationship functioning after controlling for attachment anxiety and avoidance?) with a more conservative effect size (f2 = 0.04). Results of this power analysis indicated that the required sample size was 326 participants (α set to 0.006, power to 0.80, and number of predictors to 7). Therefore, 351 individuals who confirmed to meet the inclusion criteria were recruited via Prolific. Thirteen participants reported having a romantic relationship and/or living with their partner for less than one year. Two participants reported their cohabitation duration as more than one year but one of them reported their relationship status as ‘living separately’ and the other reported it as ‘Moving in together soon after previously living together’. Furthermore, one participant did not respond to the attention check item correctly. Therefore, 16 participants were excluded, and analyses were conducted with the remaining 335 participants with a mean age of 38.09 (SD = 11.44, Range = 21–76). Of the participants, 168 identified as women, 164 as men, one as trans woman, one as non-binary, and one as genderqueer woman. In terms of relationship status, 314 participants were cohabiting, 17 were engaged and 4 were married. Detailed participant information can be found in Supplement Table 1.

Procedure

The study was ethically approved by the Faculty of Social Sciences Research Ethics Review Committee of Vrije Universiteit Amsterdam and pre-registered on the Open Science Framework (see https://osf.io/f4sjw). At the beginning, participants were informed about the study, and they voluntarily consented to participate in it. They were also informed that they were free to withdraw at any time without giving a reason and that their responses would be kept confidential by the researchers. Participants responded to the measures (see Table 1 for means and standard deviations) in the given order below and were paid two GBPs.

Table 1 Descriptive Statistics and Zero-order Correlations among the Study Variables
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Measures

Demographic information

Participants were asked to respond to questions about background demographic information such as age, gender identity, relationship duration, and so on.

Spontaneous self-affirmation

Spontaneous self-affirmation was measured with a 13-item scale developed by Harris et al. (2019). The scale measures to what extent people think about their strengths (e.g., ‘I find myself thinking about the things I am good at.’), values (e.g., ‘I find myself thinking about my principles’), and social relations (e.g., ‘I find myself thinking about people who are important to me’) when they feel threatened or anxious by people or events. Participants were asked to report their level of agreement on each item using a scale ranging from 1 (Disagree completely) to 7 (Agree completely). As recommended by Harris et al. (2019), we first computed strengths, values, and social relations scores by averaging items measuring each construct. Then, we averaged strengths, values, and social relations scores to compute the spontaneous self-affirmation scores. The reliability coefficient for the total scale was computed as 0.94.

Relationship satisfaction

Relationship satisfaction was measured via five items (e.g., ‘I feel satisfied with our relationship’) from the satisfaction subscale of the Investment Model Scale (Rusbult et al., 1998). Participants were asked to report their level of agreement on each item using a scale ranging from 0 = ‘Do not agree at all’ to 8 = ‘Agree completely’. The five items (α = 0.96) were averaged to compute the satisfaction scores.

Relationship commitment

Relationship commitment was measured with the seven-item (e.g., ‘I want our relationship to last for a very long time.’) commitment subscale of the Investment Model Scale (Rusbult et al., 1998). Participants were asked to rate their level of agreement on a scale ranging from 0 = ‘Do not agree at all’ to 8 = ‘Agree completely’. Two items were reverse coded and then the seven items (α = 0.86) were averaged to compute the relationship commitment scores.

Intimacy

Intimacy was measured with the 15-item (e.g., ‘I give considerable emotional support to my partner.’) intimacy subscale of the Triangular Love Scale (Sternberg, 1997). Participants were asked to report their level of agreement with each item on a scale ranging from 1 = ‘Not at all’ to 9 = ‘Extremely’. The fifteen items (α = 0.97) were averaged to compute the intimacy scores.

Conflict frequency

Conflict frequency was measured by asking participants to indicate how often they had a difference of opinion, disagreement, fight, or argument with their partner about nine issues (e.g., money, children, family, or in-laws) on a scale ranging from 1 = ‘Never’ to 7 = ‘Very often’ (cf., Kluwer et al., 2020). We averaged the nine items ( = 0.84) to compute the conflict frequency scores.

Conflict resolution styles

The Conflict Resolution Inventory developed by Kurdek (1994) was used to measure the resolution styles participants use to deal with arguments or disagreements with their partners. The inventory consists of 16 items measuring four conflict resolution styles: conflict engagement (e.g., ‘Launching personal attacks’), positive problem solving (e.g., ‘Focusing on the problem at hand’), withdrawal (e.g., ‘Remaining silent for long periods of time’) and compliance (e.g., ‘Being too compliant’). Each style was measured with four items. Participants were asked to rate how frequently they used each style on a scale ranging from 1 = ‘Never’ and 5 = ‘Always’. We averaged the items measuring each style to compute the conflict engagement ( = 0.86), positive problem solving ( = 0.81), withdrawal ( = 0.86), and compliance ( = 0.88) scores.

Attachment

The 12-item Experiences in Close Relationships Scale-Short Form (Wei et al., 2007) was used to measure adult attachment patterns in intimate relationships. The scale consists of two dimensions, attachment anxiety (e.g., ‘My desire to be very close sometimes scares people away’) and attachment avoidance (e.g., ‘I am nervous when partners get too close to me’), each of which was measured with 6 items. The participants were asked to report their level of agreement on each item on a scale ranging from 1 = ‘Strongly disagree’ to 7 = ‘Strongly agree’. After recoding reverse-keyed items, we averaged the items measuring each construct to compute the attachment anxiety (α = 0.76) and avoidance scores (α = 0.82).

Data analysis plan

First, we calculated the zero-order correlations among demographic variables (i.e., age, number of children, education (in years), and financial status), spontaneous self-affirmation, attachment dimensions (i.e., anxiety and avoidance), relationship satisfaction, commitment, intimacy, conflict frequency, and conflict resolution styles (i.e., conflict engagement, positive problem-solving, withdrawal, and compliance). Then, we conducted a series of hierarchical regression analyses to test our predictions and answer our research question. In each analysis, one of the eight relationship functioning indicators was the dependent variable. Based on previous research indicating that age, number of children, education, and financial status are important for relationships (Kowal et al., 2021), we controlled for these baseline variables in our study. We decided to include these covariates before data collection and pre-registered the use of these covariates as well. Thus, each model consisted of three steps. Demographic covariates (i.e., age, number of children, and educational and financial status) were entered in the first step followed by spontaneous self-affirmation in the second step. In the third step, the attachment dimensions of anxiety and avoidance were entered into the model to explore whether spontaneous self-affirmation was uniquely associated with the indices of relationship functioning over and above attachment anxiety and avoidance. As the same regression analysis was conducted eight times for each relationship functioning measure, we applied a Bonferroni correction and used a critical p-value of α = 0.006. All the above-mentioned analyses were preregistered (see https://osf.io/f4sjw). Additionally, we conducted the same regression analyses without controlling for the demographic covariates in the first step.Footnote 2

Results

As can be seen in Table 1, the results of correlation analyses showed that spontaneous self-affirmation positively correlated to relationship satisfaction, commitment, intimacy, positive problem-solving, age, number of children, and financial status and negatively correlated to withdrawal, attachment anxiety, attachment avoidance, and education.

Examining the results of the regression analyses (see Tables 2 and 3),Footnote 3 in the first step, age was negatively associated with relationship satisfaction (B = − 0.04, SE = 0.01, β = − 0.22, p < .001) and intimacy (B = − 0.02, SE = 0.01, β = − 0.19, p = .001), while financial status was positively associated with relationship satisfaction (B = 0.49, SE = 0.14, β = 0.19, p = .001) and negatively with conflict frequency (B = − 0.23, SE = 0.08, β = − 0.16, p = .003). That is, while older participants reported less relationship satisfaction and intimacy, participants with higher financial status reported higher relationship satisfaction and lower conflict frequency.

Table 2 Results of the hierarchical regression analyses predicting relationship satisfaction, commitment, intimacy, and conflict frequency
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Table 3 Results of the hierarchical regression analyses predicting conflict resolution styles
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In the second step, supporting our predictions, spontaneous self-affirmation was positively linked to relationship satisfaction (B = 0.40, SE = 0.08, β = 0.27, p < .001, H1a), intimacy (B = 0.25, SE = 0.06, β = 0.22, p < .001, H1b), relationship commitment (B = 0.21, SE = 0.06, β = 0.19, p < .001, H1c), and constructive conflict resolution style of positive problem-solving (B = 0.13, SE = 0.04, β = 0.19, p = .001, H1e). That is, participants who tend to spontaneously self-affirm reported having a more satisfying and intimate relationship, being more committed to their relationship, and using more constructive styles in conflicting situations. Spontaneous self-affirmation was not associated with conflict frequency (B = 0.00, SE = 0.04, β = 0.00, p = .995, H1d) and destructive conflict resolution styles (H1f) of conflict engagement (B = − 0.09, SE = 0.04, β = − 0.14, p = .013), withdrawal (B = − 0.10, SE = 0.04, β = − 0.14, p = .015), and compliance (B = − 0.05, SE = 0.04, β = − 0.07, p = .192).

In the third step, attachment anxiety was negatively associated with relationship satisfaction (B = − 0.22, SE = 0.07, β = − 0.14, p = .001) and positively associated with conflict frequency (B = 0.20, SE = 0.04, β = 0.23, p < .001) and destructive conflict resolution styles of conflict engagement (B = 0.23, SE = 0.03, β = 0.34, p < .001), withdrawal (B = 0.18, SE = 0.04, β = 0.24, p < .001) and compliance (B = 0.23, SE = 0.04, β = 0.30, p < .001). Attachment avoidance, on the other hand, was negatively related to relationship satisfaction (B = − 0.93, SE = 0.08, β = − 0.53, p < .001), commitment (B = − 0.73, SE = 0.06, β = − 0.56, p < .001), intimacy (B = − 0.85, SE = 0.06, β = − 0.63, p < .001 ), and constructive resolution style of positive problem-solving (B = − 0.30, SE = 0.04, β = − 0.38, p < .001) and positively with conflict frequency (B = 0.33, SE = 0.05, β = 0.34, p < .001 ) and destructive conflict resolution styles of conflict engagement (B = 0.20, SE = 0.04, β = 0.26, p < .001), withdrawal (B = 0.25, SE = 0.05, β = 0.29, p < .001) and compliance (B = 0.16, SE = 0.05, β = 0.18, p = .001).

Finally, in the third step, to explore our research question, we examined the unique association of spontaneous self-affirmation with indices of relationship functioning after controlling for its overlap with attachment anxiety and avoidance. Results indicated that spontaneous self-affirmation was only positively associated with relationship satisfaction (B = 0.21, SE = 0.06, β = 0.14, p = .001) after controlling for attachment anxiety and avoidance (see Supplement Table 2 for the overview of hypotheses and research questions). Finally, the results of the regression analyses without demographic covariates generated a similar pattern of results (see Supplement Table 3a and 3b).

Discussion

This study aimed to investigate the association between spontaneous self-affirmation and indices of relationship functioning. It was hypothesized that increased spontaneous self-affirmation in response to stressful events would be related to better-functioning relationships.

Our findings provided supporting evidence for our predictions that spontaneous self-affirmation was associated with increased relationship satisfaction (H1a), intimacy (H1b), commitment (H1c), and constructive conflict resolution styles (H1e) after controlling for age, education, number of children, and financial status. That is, individuals who are more likely to self-affirm spontaneously, reported having more satisfying relationships, being more committed to their relationships, having more intimate relationships with their partners, and using more constructive communication patterns in response to conflicting interactions. These results fit with previous research indicating that spontaneous self-affirmation is beneficial for well-being (e.g., Jessop et al., 2022) and mental health (Harris et al., 2022). They are also consistent with previous studies indicating that experimentally manipulated self-affirmation benefits relationships via increasing adaptive responses such as positive other-directed feelings (Crocker et al., 2008), or decreasing defensive responses such as blaming the victim (Schumann, 2014). However, this is the first study showing that spontaneous self-affirmation is a potential individual difference variable that is beneficial for relationships. It might be that individuals who more spontaneously self-affirm are more likely to adaptively cope with relationship-based self-threats, which, in turn, reflects positively on their relationships. This might suggest that interventions encouraging individuals to spontaneously self-affirm in response to relationship-based threats might result in improved relationships. In line with this, a previous study (Schumann et al., 2021) indicated that teaching participants to reflect on important values in response to conflicting situations resulted in more constructive conflict coping and higher marital quality at one-year follow-up. Future research might also teach individuals to reflect on personal strengths and social relations in response to relationship-based threats. On the other hand, our results indicated that spontaneous self-affirmation was not associated with conflict frequency (H1d) and destructive conflict resolution styles (H1f). This might suggest that spontaneous self-affirmation benefits relationships by improving positive aspects (e.g., constructive conflict resolution) but not by decreasing negative aspects (e.g., destructive conflict resolution). However, this suggestion should be carefully investigated in future research.

Additionally, supporting our predictions, spontaneous self-affirmation was negatively related to attachment anxiety and avoidance. Negative evaluations of self and others are among the main characteristics of anxiously and avoidantly attached individuals respectively (Mikulincer & Shaver, 2007). Therefore, it is not surprising that there is a shared variance between spontaneous self-affirmation and attachment anxiety and avoidance. We further tested whether spontaneous self-affirmation was associated with relationship functioning over and above these two established predictors of relationship functioning. Consistent with previous research (Joel et al., 2020) attachment anxiety and/or avoidance were strongly related to indices of relationship functioning such that lower levels of attachment avoidance and anxiety were related to better functioning in relationships. After controlling for the attachment dimensions, spontaneous self-affirmation only had a unique variance with relationship satisfaction. This indicates that spontaneous self-affirmation is a potential resource for a satisfying relationship, but its shared variance with attachment is mostly responsible for its association with relationship functioning indicators.

When the results regarding demographic covariates are considered, older participants were found to have lower levels of relationship satisfaction and intimacy, and participants with higher financial status were found to have higher relationship satisfaction and lower conflict frequency in their relationships. These results are consistent with previous research (Kowal et al., 2021). However, contrary to previous research (Kowal et al., 2021), none of the other covariates were linked to indices of relationship functioning. Our results suggest that older ages and lower financial status might pose a risk to relationship functioning.

Limitations and future research directions

Our study provides promising findings for relationship research, but our cross-sectional design prevents us from making causal inferences about the association between spontaneous self-affirmation and relationship functioning. Even though previous research indicates that experimentally induced self-affirmation has positive effects on relationships (e.g., Schumann, 2014), our findings cannot rule out that having a good relationship results in greater spontaneous self-affirmation. Therefore, future longitudinal studies are needed to investigate the direction of the association between spontaneous self-affirmation and relationship functioning. For instance, conducting a daily diary study might be beneficial to clarify whether spontaneous self-affirmation predicts better functioning in relationships in the face of daily relationship threats. Furthermore, although spontaneous self-affirmation was measured with a reliable and valid scale developed by Harris et al. (2019), participants might not be able to recall occasions where they spontaneously self-affirmed. A daily diary study might also enable the measurement of spontaneous self-affirmation at different time points. This way, participants can provide more accurate information about whether they engage in spontaneous self-affirmation.

Additionally, some level of heteroscedasticity was observed in the regression models predicting satisfaction and intimacy. While Tabachnick and Fidell (2013) state that heteroscedasticity does not completely invalidate the analysis, they acknowledge it tends to weaken it. As this is the very first study testing these associations, future research will also be beneficial to confirm the generalizability of our findings. Additionally, heteroscedasticity might result from a third variable moderating the association between an independent variable and a dependent variable (Tabachnick & Fidell, 2013). Therefore, identifying factors that moderate the association of spontaneous self-affirmation with relationship satisfaction and intimacy will take this research a step further and establish the boundary conditions under which these associations are stronger. Related to this, in this study, we were motivated to explore whether spontaneous self-affirmation was uniquely associated with the indices of relationship functioning over and above attachment anxiety and avoidance. However, future research might also want to investigate potential different roles that attachment styles could play in the relationship between spontaneous self-affirmation and relationship functioning (e.g., whether or not it acts as a moderating variable). In addition, while there is no consensus on the indicators of relationship functioning (Vitek & Yeater, 2021), we operationally defined it using relationship satisfaction, commitment, intimacy, conflict frequency, and conflict resolution styles, drawing on previous studies (e.g., Mikulincer & Shaver, 2007; Vitek & Yeater, 2021). Nevertheless, future research is recommended to explore the associations between spontaneous self-affirmation and less commonly utilized indicators of relationship functioning.

In conclusion, this study extended previous research by showing that spontaneous self-affirmation is an individual difference variable associated with relationship functioning. It is important to reveal factors related to well-functioning relationships, and this study provides the first evidence showing that spontaneous self-affirmation is among these factors. Herewith we add both to the literature on self-affirmation and the literature on relationship functioning. This might indicate that interventions that encourage people to spontaneously self-affirm in response to relationship threats might benefit their relationships. However, more studies using different methods are needed to provide evidence for the predictive role of spontaneous self-affirmation on relationship functioning.