Rusbult's Investment Model

Rusbult's Investment Model of Relationships

Rusbult et al.'s (2001) investment model is an extension of social exchange theory, which suggests that people in relationships constantly analyse the cost and benefits of a relationship. Rusbult explores how satisfaction, comparisons with alternatives and investment levels affect commitment rather than focusing on the cost and benefit analysis in social exchange theory.

The most critical factor of Rusbult’s (1980, 1983) theory is people's investment in relationships, affecting commitment and the stability of a relationship.

According to Rusbult (1980):

Rusbult also divided investments into intrinsic and extrinsic categories. The intrinsic category refers to things we put directly into a relationship, such as money and time. In contrast, extrinsic investments result from relationships and are formed due to the association with current behaviours in relationships, such as happy memories and shared friends.

Rusbult's Investment Model of Commitment

According to Rusbult (1980, 1983), couples maintain levels of commitment in relationships for three reasons:

1. Satisfaction: How well the relationship satisfies the person's needs and wants.

2. Comparison with alternatives: How other relationships compare to the current one, and how well they could fulfil needs in comparison (especially if the current one does not fulfil needs well).

3. Investment size: How much a person has put into a relationship overall.

Fig. 2 - Couples commit to the relationships due to satisfaction, comparison and investment.

These reasons link to commitment and stability in relationships.

How can we distinguish between Rusbult's Investment Model and Social Exchange Theory?

Rusbult's investment model is an extension of social exchange theory, which suggests that people in relationships are constantly undergoing an analysis of the cost and benefits of them being in that relationship, including their level of investment (time, effort. money etc.) and comparison to other past or potential partners.

Rusbult explores how satisfaction, comparisons with alternatives and investment levels affect commitment, rather than focusing on the cost and benefit analysis in social exchange theory. Social exchange theory concentrates more on how people seek to minimise costs and maximise rewards.

Investment Model Examples: Research

There are a few prominent studies concerning Rusbult’s Investment Model as examples of real-world application of relationship investment models.

Le and Agnew (2003)

Le and Agnew (2003) conducted a meta-analysis of 52 studies with 11,582 total participants and discovered that satisfaction, comparison with alternatives, and investment greatly contributed to commitment.

Commitment levels were significantly associated and predicted whether someone would remain in the relationship overall.

Impett, Beals, and Peplau (2002)

Over 18 months, Impett, Beals, and Peplau (2002) conducted a longitudinal study of 3,627 married couples (husbands aged 17 to 79 years and wives aged 17 to 77 years).

They found that there was a strong correlation between stability and commitment. Spouse satisfaction, the investment they put into the relationship, and potential alternatives were predictors of their levels of commitment to the relationship.

Fig. 3 - Spouse satisfaction is an important factor in a committed relationship.

Rhatigan and Axsom (2006)

Rhatigan and Axsom (2006) studied a group of shelter-based battered women and their reasons for staying with their partners. They were interested in why they decided to stay committed to abusive relationships and investigated it using the parameters set out by Rusbult's investment model.

Bui, Peplau, and Hill (1996)

Using multiple regression analyses, Bui, Peplau, and Hill (1996) studied 167 heterosexual couples over 15 years (1972-1987).

They found that rewards and costs greatly influenced satisfaction, whilst the availability of alternatives, investment, and satisfaction influenced commitment, supporting Rusbult’s theory. Again, they found that Rusbult's model fits quite well with the data (using path analyses), and associations were similar for men and women.

Evaluation of Rusbult's Investment Model

Understanding the weaknesses and strengths of Rusbult’s investment model is important. Like all theories on human behaviour, we must establish how robust the knowledge behind the theory is.

Weaknesses

Weaknesses include correlational research and reductionism.

• Rusbult’s investment model suggests that investment equals commitment. However, this is a correlation as we cannot accurately predict or quantify investment since it differs from person to person. The model cannot prove causation.

• Goodfriend and Agnew (2008) argued that there are few empirical analyses of investments and their predictive power of state or fate of relationships. They suggested that the investment model is oversimplified. Partners may stay in a relationship to see plans realised despite not ‘investing’ in such plans in the present moment.

Strengths

Strengths include research support, self-report techniques, and an explanation for staying in abusive relationships. They also include cross-cultural applications and enrichment of social exchange theory.

• As we have seen, research from Le and Agnew (2003), Bui, Peplau, & Hill (1996), Rhatigan and Axsom (2006), and Impett, Beals, and Peplau (2002) support Rusbult’s model.

• Although self-report techniques in studies of Rusbult’s model have real-world validity and applications, the nature of this data collection is that they are subjective but unreliable. Therefore, whilst Rusbult’s model is not remarkably scientific, it has many real-world applications.

• Rusbult’s investment model explains why someone would stay in an abusive relationship, showing that it has real-world validity. If someone has invested much in their relationships, such as time, money, or children, they may stay despite the present costs outweighing the benefits.

• Le and Agnew (2003) found in a meta-analysis of 52 studies that the investment model is valid in individualist and collectivist cultures. Associations between commitment and bases vary minimally depending on demographic factors (such as ethnicity). It has also been proven to explain commitment in different cultural subgroups, such as the LGBTQIA+ community.
• The investment model explains why people stay in relationships despite unbalanced rewards and costs, which social exchange theory fails to do.