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."