Unmasking the Flaws of Triplet-Triplet Attraction Effect Measures: Via Mathematical Analysis and Agent-Level Simulations

The ‘attraction effect’ or ‘asymmetric dominance effect’ is a widely studied phenomenon in decision-making, challenging the principle of regularity in rational choice theory. It posits that the introduction of a third option, similar but inferior to one of the available options in a binary choice set, increases the choice share of the dominating option. While the standard attraction effect is pervasive, recent studies have found inconsistent results. Some researchers attribute these inconsistencies to boundary conditions that constrain the effect, suggesting that studies failing to meet these criteria unsurprisingly report inconsistent effects. This paper aims to clarify the presence, strength, and direction of the attraction effect through two approaches: first, by analyzing contemporary metrics for measuring context effects and demonstrating their susceptibility to false positives and negatives; and second, by examining the boundary condition of strong prior trade-off—a biased preference for one choice in the baseline set—and its impact on metric vulnerability.