Rustbult's investment model

• Rusbult’s (2011) investment model


  investment theory is another development of social exchange theory

  • suggests that when deciding to continue a relationship, we don’t just consider current level of satisfaction, but also potential alternative relationships and how much we have already invested into the existing relationship.
  • Commitment = (Satisfaction level + Investment) - Alternatives
• investment size


  what distinguishes investments from rewards/costs is that  once invested in a relationship, they cannot easily be recovered in a break up or may be difficult to divide.
• intrinsic investment 


  resources put directly into the relationship such as emotional work, time spent, and self disclosures
• extrinsic investment


  resources that used to be outside of the relationship but become more strongly connected to the relationship over time such as shared friendships, a shared home, activities, memories, and material possessions.
• commitment


  increased by the amount of investment a person has made. The person feels locked into the relationship as ending it would mean sacrificing those resources
• Rusbult

  • questionnaire study of male and female ppts in heterosexual relationships
  • Findings: costs + benefits applied less at the start of the relationship, but were considered more as the relationship developed
  • Also costs + benefits were considered against alternatives who became less attractive over time as commitment developed, and as satisfaction increased, so did commitment.
  • evidence for this model as findings indicated that as relationships developed increased investment size resulted in greater commitment and a reduction in the perception of the quality of the alternatives.
• Lee and Agnew’s (2003)

  • meta-analysis of studies relating to similar investment models found that satisfaction, comparison with alternatives and investment were all strong indicators of commitment to a relationship. This importance was the same across cultures, genders, and also applied to homosexual relationships.
• (strength/weakness)

  • Many of the studies relating to investment in relationship rely on self-report technique. Whilst this would be perceived as a less reliable and overly-subjective method in other areas, when looking at the amount an individual feels they are committed to a relationship, their own opinion and the value that they place on behaviors and attributes is more relevant than objective observations.
• real-life applications

  • it can help explain why partners suffering abuse continue to stay in abusive relationships – although satisfaction may be very low, investment size (for example, children) may be very high, and they may lack alternative potential partners, so it is better at explaining many relationships than SET or Equity theory.