9.3.3 Rusbult's Investment Model

• Rusbult’s Investment Model (RIM) is based on two of the principles of Social Exchange Theory (SET):
  • Satisfaction with the relationship based on the Comparison Level (CL) i.e. few costs, more rewards, in short: profit guaranteed
  • Comparison Level with alternatives (CLalt) which involves one of the partners wondering whether the ‘grass is greener on the other side’ i.e. should they pursue a new relationship with someone else or stay in the current relationship
  • Investment size (not a feature of SET and is explained in the next section)
• When all three of the above criteria are addressed, then commitment to the relationship will follow according to RIM (2011)
• RIM - like Social Exchange Theory and Equity Theory - is an economic theory of relationships but  it attempts to refine and expand on some aspects of SET

Figure 1: Rusbult’s Investment Model

• Investment in a relationship consists of how much - which refers to quality, not just quantity - each person has brought to the relationship  (investment size refers to the overall value of that investment)
• As all financial advisors will tell potential investors, investments can lose value as well as increase over time and this is particularly true of relationships: if the relationship ends, both partners are likely to lose out financially, emotionally, and materially
• There are two types of investment according to the model:
  • Intrinsic investment - this comprises everything that each individual has brought separately to the relationship: money, possessions, time, energy, episodes of self-disclosure
  • Extrinsic investment - this comprises everything that is a result of the relationship itself: children, joint possessions, friends, holidays, joint memories
• If both partners have substantially invested in the relationship (by investing materially and/or emotionally) then the relationship is likely to survive, even if satisfaction is low at times (this has some relevance to the cognitive bias of the sunk-cost fallacy)
• In short, RIM explains why some relationships can persist even when satisfaction levels are low and alternatives exist: Rusbult argues that this is due to commitment being more important overall than satisfaction in a relationship

• Commitment refers to how determined a couple is to stay together and to weather the ‘slings and arrows’ of relationship turbulence (apologies for the mixed metaphors)
• If a couple is committed to the relationship it does not necessarily mean that they are madly in love with (or even like!) each other but they have invested in the relationship and they want it to succeed 
• According to Rusbult, commitment helps to maintain a relationship e.g. a couple will attempt to work through a ‘rough patch’ to repair the relationship as both of them have made a commitment  (even though this may, at times be unpleasant or involve hard work)
• Some strategies that RIM suggests to maintain commitment include:
  • Sacrifice on both sides - this means that each partner is willing to put their other half first rather than pursuing selfish motivations
  • Positive illusions created - this involves an almost impossible idealisation of each other and an unwillingness to acknowledge that alternatives exist plus there is the tendency to view other people’s relationships as inferior to their own
  • Accommodation - this involves not engaging in petty point-scoring: the couple will do what they can to protect the relationship from harm
  • Forgiveness - even when this may be difficult e.g. if one of the partners has an affair for example

Commitment is not easy but it has long-term benefits.

Research which investigates Rusbult’s Investment Model

• Le & Agnew (2003) - a meta-analysis of 52 studies comprising a total of 11,000 participants from 5 countries which concluded that satisfaction, CLalt and investment size all predicted commitment
• Impett et al. (2002) - a longitudinal study of 3,627 married couples which found a significant positive correlation between satisfaction and commitment with investment size also predicting commitment
• Rusbult & Martz (1995) - interviews conducted with women living in a shelter for ‘battered’ women revealed that those who felt more invested in the relationship, who had fewer alternatives due to lack of money and who expressed greater satisfaction with the relationship were more likely to return to their abusive partner than women who reported different feelings and circumstances

Evaluation of Rusbult’s Investment Model

Strengths

• Research in this field such as Le & Agnew (2003) used a large sample and quantitative data which means that the findings are robust and able to withstand statistical analysis which in turn increases their reliability
• Recognising that commitment is a key factor linked to investment size explains why someone would stay in an abusive relationship

Weaknesses

• It is difficult to separate the key components of RIM e.g.  intrinsic and extrinsic investments may overlap or be difficult to to distinguish from each other
• The theory could be used to perpetuate abusive relationships by the abuser i.e. knowing that the abused partner is committed to the relationship and has few alternatives could grant power to the abusive partner