Before the investment model, commitment research mostly asked how much people loved each other. Here is how the field moved to a three-part, testable framework instead.
The Old Framing: Satisfaction as a Stand-In
Earlier relationship research leaned heavily on satisfaction as a proxy for commitment, effectively assuming happier relationships were the stable ones. That framing struggled with an obvious counterexample: some clearly unhappy relationships persisted for years, while some satisfying ones ended quickly.
1980: Rusbult Splits Commitment Into Three Parts
Caryl Rusbult's founding study tested whether satisfaction alone predicted who stayed together. It didn't — quality of alternatives and investment size each added independent predictive power on top of it. That was the shift: commitment became three testable, separate inputs instead of one feeling.
1983: Proving the Bases Actually Move
A single snapshot couldn't show whether satisfaction, alternatives, and investment were stable traits or shifting states. Rusbult's 1983 follow-up tracked real couples over time and found all three genuinely move month to month — treating commitment as dynamic rather than fixed.
2003: The Meta-Analysis That Settled It
Le and Agnew's 2003 meta-analysis pooled 52 studies and over 11,000 participants. All three predictors held up across genders, cultures, and relationship types, making the investment model one of the most consistently replicated frameworks in relationship science.
Why This History Still Matters
Each study closed a specific gap the previous one left open: does satisfaction alone explain staying (no), do the bases actually shift over time (yes), and does the pattern hold outside the original sample (yes, broadly). That's what makes the three-way score more than a personality quiz.
Curious what your own three bases look like using this exact framework? Take the free Relationship Commitment Test and see the breakdown behind your score.
Frequently Asked Questions
What did commitment research look like before Rusbult's model?
Earlier work leaned heavily on satisfaction as a stand-in for commitment, effectively assuming happier relationships were more stable ones. That framing struggled to explain why some clearly unhappy relationships persisted for years.
What changed with the 1980 investment model?
Rusbult's original study found satisfaction alone did not predict who stayed together, quality of alternatives and investment size each added independent predictive power on top of it, splitting commitment into three testable, separate inputs for the first time.
How did the 1983 study build on that?
It followed real couples over time rather than taking a single snapshot, and found all three bases genuinely move month to month, treating commitment as a dynamic state rather than a fixed trait someone simply has or lacks.
How settled is the model today?
Very. Le and Agnew's 2003 meta-analysis pooled 52 studies and over 11,000 participants and confirmed all three predictors generalize across genders, cultures, and relationship types, making it one of the most consistently replicated frameworks in the field.