Yes. Specifically, I'm always struck by the idea that someone offering me $100 right now, before I let them out of my sight, is more likely to deliver. If it were between me leaving and them mailing (or wiring) $100 later that day (or so they say) vs. $150 next week, clearly I'll take the $150.

But Yvain talks about the reward at time t vs the larger one at time t+1 becoming more tempting only as you get sufficiently close to t - so, if this has been measured in real people, some researchers must have avoided the obvious "we'll get back to you" credibility problem (I didn't follow cites looking for details, however).