The Ultimatum Game
Are people truly fair or are they afraid that their offer will get rejected?
The mode is at a 50-50 split, meaning many proposers are willing to share equally, but this could also reflect strategic behavior, i.e., trying to avoid getting their offer rejected.
In the dictator game, where the recipient has no power to reject the offer, the most common allocation is still 50-50, with the next most common offer at 0.
Contrary to the predictions of standard economic theory, it looks like people are far from selfish. Transfer amounts in the Dictator Game are significantly different from zero!