Let me end with a cautious note. Recently there have been some doubts raised about the external validity of dictator games, or the extent to which the results generated in these lab studies carry over to non-artificial or natural settings. For instance, Jeffrey Winking and Nicholas Mizer (2013) had a confederate approach an individual at a bus stop in Las Vegas, and “pretended to notice chips in his pocket, stopped briefly and claimed to the participant that he was late for a ride to the airport and asked the individual if he/she wanted the casino chips, which he did not have time to cash in,” and which were worth $20 (2013: 290). Ten feet away with his back turned to the participant was another confederate. The confederate with the chips would also add, “I don’t know, you can split it with that guy however you want” while pointing towards the second confederate (2013: 290). However, in stark contrast to the results earlier, here every single participant kept all $20 for themselves (2013: 291). Several writers have claimed that external validity might be limited because the laboratory results for dictator games could be heavily influenced by experimenter demand effects (Zizzo 2010, 2013, Winking and Mizer 2013.