Specification: Theories of romantic relationships: Rusbult’s investment model of commitment, satisfaction, comparison with alternatives and investment

Rusbult’s Investment Model 

The Investment Model was proposed by Rusbult (1980) as a development of Social Exchange Theory (SET). The rationale for developing SET further was that many couples stay together despite the costs outweighing the rewards, so there must be other factors that keep them together. Rusbult's Investment Model attempts to explain what these other factors might be. 

According to Rusbult's, there are three major factors that lead to commitment in relationships: satisfaction level, comparison with alternatives and investment size. 

Commitment

Commitment, in terms of romantic relationships, refers to the partner’s desire to remain in a couple and reflects their intention to have a long-term future together. Rusbult believes that commitment acts as a maintenance factor in romantic relationships, even if the couple encounter difficulties in their partnership, given that they will not want to see their respective investments going to waste by breaking up. This means that a couple will attempt to work through their ‘rough patch’, to repair their relationship, given the commitment they have both made. 

Commitment can also be seen as a consequence of increasing dependence in a romantic relationship. For example, if a partner is relatively satisfied with their relationship, has no suitable alternatives which are more desirable and has investments in the partnership that they do not want to walk away from, dependence upon that relationship may be the result. 

Satisfaction

Satisfaction level is based upon the notion of comparison level as seen in Social Exchange Theory. Partners will have a higher level of satisfaction with their relationship if they receive more rewards (e.g. companionship, attention, emotional support) and incur fewer costs (e.g. arguments, time). To measure satisfaction, a partner must internally offset the perceived positivity from the relationship against any negativity, with an emergent result that feels gratifying to them personally. Satisfaction may be felt with equal domestic task sharing divisions in the household, compassionate interactions between both partners and through the meeting of sexual desires. 

Comparison with Alternatives 

Rusbult’s notion of comparison with alternatives also echoes the principle of the same name within Social Exchange Theory. Comparison with alternatives is a judgement that is made by one, or both, of the partners in a romantic relationship concerning whether or not they could receive greater satisfaction by terminating the current partnership. Partners tend to be committed to a relationship if, when asking themselves: 'Is there a better alternative to satisfy my needs?', the answer is ‘no’. Alternatives can also include the individual staying on their own and not engaging in romantic relationships at all. 

Investment in Romantic Relationships

For Rusbult, the most important factor that maintains commitment to a relationship is investment. Investment refers to the number of resources, both tangible, like money or possessions, and intangible, such as happy memories together, that people will lose if they leave the relationship. 

The model proposes two types of investment: intrinsic and extrinsic. Intrinsic investment comprises the things partners put directly into the romantic relationship, such as effort, money, possessions and selfdisclosure. Extrinsic investment refers to the things that are brought to people's life through the relationships, such as children, friends and shared memories. Because both intrinsic and extrinsic investments can potentially be lost if relationships end, Rusbult et al. (2011) concluded that the bigger the investment, the more likely people are to stay in the relationship. Therefore, it is the investment size that influences commitment to relationships, rather than just the level of satisfaction or existence of potential alternatives. 

Research Examining the Investment Model

There are numerous research studies supporting the Investment Model. Impett, Beals and Peplau (2002) conducted a longitudinal study using a large sample of 3,627 married couples over an 18-month period. The age range of the participants was 17-79 years old for the males and 17-77 for the females. Results indicated that satisfaction, comparison with alternatives and investment were all important factors in determining commitment to a marriage, supporting Rusbult’s ideas. They found that stability of the marital relationships positively correlated with commitment shown by the partners which remained an accurate predictor when measured again 18-months later. 

Rhahgan and Axsom (2006) interviewed a group of females who were resident in a women’s refuge and asked them why they had remained in an abusive relationship. They found that three factors identified by Rusbult et al. - satisfaction, comparison with alternatives and investment - featured in participants' decision to stay with their partner. The highest level of commitment was shown by those women who felt that their investment in the relationship was high and their economic alternatives i.e. financial, were poor. 

Le and Agnew (2003) 

Aim: To investigate Rusbult’s Investment Model of Relationships. 

Method: A meta-analysis was conducted of 53 studies comprising 60 independent samples and 11,582 participants in total spanning from the late 1970s until the late 1990s. Data from five countries were represented (UK, USA, Israel, Taiwan and the Netherlands) and the division of male and female participants was 54% and 46% respectively. Each piece of research included in the meta-analysis had explored the main components of Rusbult’s Investment Theory: satisfaction, comparison with alternatives, investment and their impact on commitment to the relationship. 

Results: It was found that satisfaction with the relationship, comparison with alternatives, and investment in the partnership all correlated significantly with commitment to that union. The strongest correlation coefficient of +0.68 was reported in the relationship between satisfaction and commitment, followed by the association between comparison with alternatives (-0.48) and then investment size and commitment (+0.46). Perhaps understandably, a lack of commitment to the relationship was a significant predictor of relationship breakdown. 

Conclusion: The results indicate support for Rusbult’s Investment Theory model of romantic relationships with individuals showing the highest level of commitment to a partnership choosing to remain in the relationship. On the other hand, partners with lower levels of commitment were more likely to leave. 

Evaluation of the Investment Model

There are potential methodological issues with studying the Investment Model. Some psychologists point out that most evidence for the Investment Model comes from interviews and questionnaires, which are known to be subjective and unreliable. However, other researchers argue that, because satisfaction, investment and commitment are subjective values and depend on people's perception, using self-report techniques is an appropriate way to test the Investment Model. Therefore, data obtained through self-report techniques may provide a more realistic picture of reasons for relationship satisfaction and how it is related to investment and commitment, therefore making Investment Model more valid.  

The Investment Model provides an explanation for why people stay in abusive relationships. According to the model, if a partner feels that the investment they made into relationships will be lost if they leave, they are more likely to stay in a relationship even when the costs are high (such as physical or emotional abuse) and rewards are few. Research into abusive relationships supports this idea. For example, Rusbult and Maltz (1995), in their study of 'battered' women, found that women were more likely to return to an abusive partner if they felt they had invested in the relationship and they did not have any appealing alternatives. This shows that the Investment Model can be applied to a wide range of relationships experiences that the SET and Equity Theory fail to explain, thus increasing the Investment Model’s application to everyday relationships.  

The majority of research into the Investment Model is correlational. This is a problem because psychologists are unable to conclude that investment causes commitment in relationships. This, therefore, limits the predictive validity of the model, as it would fail to predict which types of investment, and how much investment, is needed for a long-term commitment to a relationship to develop. Lack of predictive validity also makes the Investment Model less scientifically rigorous, as the ability to predict people's behaviour, in this case, whether or not they will stay committed to the relationship, is one of the main goals of psychology as a science. 

Extension Evaluation: Issues & Debates

Cultural bias doesn't seem to be an issue for the Investment Model. Le and Agnew’s (2003) metaanalysis of 52 studies found support for the Investment Model across individualist and collectivist cultures, such as in the USA (individualist culture) and in Taiwan (collectivist culture). Furthermore, the Investment Model, as an explanation of relationship maintenance, is also shown to be valid for different sub-groups, such as friendships, homosexual relationships, cohabiting couples, and so on. This suggests the universality of the Investment Model, making it applicable to wide range of relationships.  

The fact that the evidence for the Investment Model is found across cultures may suggest that the human need for investment and commitment to relationships developed through the process of natural selection to help people survive and reproduce. For example, parents who are committed to their relationship and invest in it will have a higher chance of ensuring their children's survival and therefore of passing on their genes. This means that the Investment Model supports the nature side of the nature-nurture debate. 

Possible Exam Questions

1. Define what is meant by investment in relation to Rusbult’s model of relationships. (2 marks)

2. Explain one difference between satisfaction and commitment in romantic relationships. (2 marks) 

3. A researcher is investigating reasons for why people stay in abusive relationships. He used semistructured interviews with victims of domestic abuse at the refuge centre, looking for a correlation between investment and commitment scores. 

a. Briefly outline one ethical issue the researcher should consider when conducting this study. (2 marks) 

b. Explain why Spearman’s rho would be a suitable inferential test to analyse the data collected by the researcher. (3 marks) 

c. Scientific research is subjected to peer review before being published in scientific journals. Describe the process of peer review. (4 marks) 

4. Describe what research has shown about the role of investment in romantic relationships. (4 marks)

5. Outline the investment model of relationships. Refer to research in your answer. (6 marks). 

6. Natasha has been married for ten years and has been increasingly unhappy in her marriage for the last few years. She often talks to her close friends about whether she should leave her husband, saying that he is becoming more and more controlling and emotionally abusive. However, she can't quite bring herself to leave him and makes excuses to avoid conversation with her husband about her unhappiness. 

Using your knowledge of the Investment Model, explain Natasha's reluctance to leave her marriage. (4 marks) 

7. Explain one strength and one limitation of the investment model of relationships. (6 marks) 

8. Discuss the Investment Model as an explanation of romantic relationships. (16 marks)