Syllabus Edition

First teaching 2025

First exams 2027

Rusbult's Investment Model (AQA A Level Psychology): Revision Note

Exam code: 7182

Claire Neeson

Written by: Claire Neeson

Reviewed by: Cara Head

Updated on

The key features of 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 and more rewards, means that profit guaranteed

    • Comparison Level with alternatives (CLalt), which involves one of the partners wondering whether they should pursue a new relationship with someone else or stay in the current relationship

  • Investment size is also crucial (see below)

  • When all three of the 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

Investment

  • 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)

  • 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

  • Commitment describes the extent to which a couple is resolved to remain together and endure the challenges and hardships that arise in their relationship

  • If a couple is committed to the relationship, it does not necessarily mean that they are in love with 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 committed (even though this may, at times, be unpleasant or involve hard work)

  • 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

Examiner Tips and Tricks

 It is vital that you can distinguish between all three of the ‘economic’ theories of relationships: 

  • SET

  • Equity Theory

  • Rusbult’s Investment Model

The theories share some similarities, but they are all distinct,t and examiners often report that students tend to confuse details of one theory with another or simply ‘lump them in together’. It would be a good idea to create a chart or table of each theory, highlighting the similarities and (more importantly) the differences between them.

Rusbult’s Investment Model = satisfaction/investment/commitment

Research which investigates Rusbult’s Investment Model

  • Le & Agnew (2003) – a meta-analysis of 52 studies comprising a total of 11,000 participants from five countries

    • It was 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 survivors of domestic abuse 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

Limitations

  • It is difficult to separate the key components of RIM; e.g., intrinsic and extrinsic investments may overlap or be difficult 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

Issues & Debates

  • RIM has been used to explain why people remain in abusive relationships, such as in Rusbult & Martz (1995)

    • While this has real-world application, it is also socially sensitive, as it could be misused to justify or normalise staying in harmful situations, especially when commitment is based on high investment and lack of alternatives

    • Psychologists must consider the ethical implications of applying RIM in such contexts

Worked Example

Here is an example of a question you might be asked on this topic which includes AO1 and AO3.

AO1: You need to demonstrate knowledge and understanding of key concepts, ideas, theories and research.

AO3: You need to analyse and evaluate key concepts, ideas, theories and research.

Q. Outline Rusbult’s Investment Model. Explain one limitation of this model as a theory of romantic relationships.

[6 marks]

AO1 = 3 marks, AO3 = 3 marks

Model answer:

AO1: Outline Rusbult's model:

  • Rusbult’s Investment Model suggests that commitment in a relationship depends on three factors: satisfaction, comparison with alternatives (CLalt), and investment

  • Satisfaction is how rewarding the relationship feels, CLalt is whether better options exist, and investment refers to what each partner has put in (e.g., time, emotions, possessions). High satisfaction and investment, plus few alternatives, lead to stronger commitment [3 marks]

AO3: Explain one limitation of the model:

  • A limitation of the model is that it may be socially sensitive. E.g., Rusbult & Martz (1995) found that women in abusive relationships were more likely to stay if they had high investment and few alternatives

  • While this supports the theory, it raises ethical concerns, as it may unintentionally justify remaining in harmful situations. Therefore, the model may oversimplify complex decisions and lack practical guidance in such cases [3 marks]

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Claire Neeson

Author: Claire Neeson

Expertise: Psychology Content Creator

Claire has been teaching for 34 years, in the UK and overseas. She has taught GCSE, A-level and IB Psychology which has been a lot of fun and extremely exhausting! Claire is now a freelance Psychology teacher and content creator, producing textbooks, revision notes and (hopefully) exciting and interactive teaching materials for use in the classroom and for exam prep. Her passion (apart from Psychology of course) is roller skating and when she is not working (or watching 'Coronation Street') she can be found busting some impressive moves on her local roller rink.

Cara Head

Reviewer: Cara Head

Expertise: Biology & Psychology Content Creator

Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding