Fair Cake-Cutting in Practice Maria Kyropouloua, Josu´eOrtegab, Erel Segal-Halevic aSchool of Computer Science and Electronic Engineering, University of Essex, UK. bQueen's Management School, Queen's University Belfast, UK. cDepartment of Computer Science, Ariel University, Israel. Abstract Using two lab experiments, we investigate the real-life performance of envy- free and proportional cake-cutting procedures with respect to fairness and preference manipulation. Although the observed subjects' strategic behavior eliminates the fairness guarantees of envy-free procedures, we nonetheless find that envy-free procedures are fairer than their proportional counterparts. 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 in- teraction and use this knowledge to improve their allocated share of the cake. Learning increases strategic behavior, but also reduces envy. Keywords: cake-cutting, Selfridge-Conway, cut-and-choose, envy, fairness, preference manipulation, experimentation and learning. JEL Codes: C71, C91, D63. Email addresses:
[email protected],
[email protected],
[email protected]. We acknowledge excellent research assistance by Andr´es Azqueta-Galvad´on, Wai Chung, Mingxian Jin, Alexander Sauer and Carlo Stern, and helpful comments from Uriel arXiv:1810.08243v3 [cs.GT] 14 Dec 2020 Feige, Herv´eMoulin and the anonymous referees of this journal and the 20th ACM confer- ence on Economics and Computation, where a preliminary version of this paper has been presented as an extended abstract. We thank Sarah Fox and Erin Goldfinch for proof-reading the paper.