Our online trust game was played by randomly assigned anonymous players who did not meet before playing. Player 1s were told that we would conduct 6 lotteries of $100. They were then told that we had allotted them 10 lottery tickets, and that they have the option to share some, none, or all of it with Player 2, who was also given 10 tickets at the outset. Then Player 1s were told that any sum shared will be tripled before giving it to Player 2, and that Player 2 will be given the same options–to return some, none, or all of it to Player 1.
Trust is measured as the amount Player 1 sends to Player 2. Since Player 2 has no incentive to return any of the money, Player 1 should pocket the 10 tickets and to pass none of them to Player 2. However, on average, both players give significantly above the equilibrium amounts, a finding that holds in an array of diverse contexts. In other words, trusting behavior on the part of Player 1 is not completely misplaced in Player 2 because Player 2 often reciprocates, thereby honoring the trust placed in them by behaving in a trustworthy manner.
Love and Carlin were examining the level of trust manifested by pairs of people who shared the same party affiliation (friendly partisans) and pairs who did not (rival partisans). Before bin Laden’s death, people showed almost twice as much trust in friendly partisans as rival partisans. That is, they shared roughly twice as many tickets with friendly partisans as with their rivals.
But after bin Laden’s death, there was no evidence of partisan bias. Participants who took part in the experiment at that point awarded far more tickets to rival partisans than did those who participated before bin Laden’s death. In fact, those who participated after his death awarded an equal number of tickets with friendly partisans and rivals alike. Love and Carlin note that this finding dovetails with the increase in trust that occurred after 9/11.
Here is a brief write-up of the experiment. This, combined with the results I discussed previously, suggests that the killing of bin Laden may have made Americans more suspicious of Muslims but less suspicious of each other.