Languages with obligatory future tense marking have higher future discount rates, across a host of behaviors. So far the paper seems solid and this observation is pretty amazing. In terms of obvious implications, this sure beats distance and color classification!
The obvious speculation is that future time marking increases the cognitive distance of future plans. It's immediately more interesting that many languages use future tense or future tense-like constructions for their subjunctive. If we put future discounting into procrastination equation terms, we could say that placing future acts into further away, less concrete categories is raising the delay, and/or lowering the expectancy.