Dynamic Inconsistency and Group Decisions

My colleague Matt Jackson and my coauthor Leeat Yariv have two new papers on dynamic inconsistency and group decisions.

The theory paper is "Collective Dynamic Choice: The Necessity of Time Inconsistency" (unfortunately I found no direct link), the abstract reads:
"We study collective decisions by time-discounting individuals choosing a common consumption stream. We show that with any heterogeneity in time preferences, every Pareto efficient and non-dictatorial method of aggregating utility functions must be time inconsistent. We also show that decisions made via non-dictatorial voting methods are intransitive."

They also have an experimental paper "Present Bias and Collective Dynamic Choice in the Lab"
"We study collective decisions by time-discounting individuals choosing a common consumption stream. We show that with any heterogeneity in time preferences, utilitarian aggregation necessitates a present bias. In lab experiments three quarters of 'social planners' exhibited present biases, and less than two percent were time consistent. Roughly a third of subjects acted as if they were pure utilitarians, and the rest chose as if they also had varying degrees of distributional concerns."