Fair Cake-Cutting in Practice

TL;DR

This study empirically evaluates envy-free and proportional cake-cutting procedures, finding envy-free methods like Selfridge-Conway to be fairer and more preferred, despite susceptibility to manipulation, and highlighting learning effects in repeated interactions.

Contribution

The paper provides experimental evidence supporting the practical effectiveness of envy-free cake-cutting procedures, especially Selfridge-Conway, in real-life fairness and manipulation contexts.

Findings

Envy-free procedures are perceived as fairer than proportional ones.

Repeated interactions lead to learning opponents' preferences and reduced envy.

Manipulation occurs frequently but does not undermine perceived fairness.

Abstract

Using a lab experiment, we investigate the real-life performance of envy-free and proportional cake-cutting procedures with respect to fairness and preference manipulation. We find that envy-free procedures, in particular Selfridge-Conway, are fairer and also are perceived as fairer than their proportional counterparts, despite the fact that agents very often manipulate them. Our results support the practical use of the celebrated Selfridge-Conway procedure, and more generally, of envy-free cake-cutting mechanisms. We also find that subjects learn their opponents' preferences after repeated interaction and use this knowledge to improve their allocated share of the cake. Learning reduces truth-telling behavior, but also reduces envy.