What causes the strength-is-weakness effect in coalition formation: Passive adoption or active selection of self-serving allocation rules?

In coalition formation, bargainers with many resources are often excluded from coalitions (the Strength‐is‐Weakness effect). Literature suggests this effect is driven by high‐resource bargainers using self‐serving allocation rules that backfire, as they prefer equity over equality (while low‐resource bargainers prefer the opposite). Four studies test 1) whether this is actually the case and 2) whether high‐resource bargainers solely consider equitable allocations or whether they consider both equity and equality but actively choose equity as an allocation rule. We find the Strength‐is‐Weakness effect even when equality rules are made salient, strengthening the idea that the high‐resource bargainers actively select equity as their framework for fairness to attempt to maximize their outcomes. The studies, also suggest an additional reason for the exclusion of high‐resource bargainers. We find that high‐resource bargainers are likely avoided because they are expected to bargain self‐servingly, making the low‐resource bargainers seek out each other.