https://www.sciencedaily.com/releases/2018/11/181105105407.htm

These are the principal findings of a study published in the journal PLOS ONE by researchers from the Universitat Rovira i Virgili, the University of Barcelona, the University of Zaragoza and the Carlos III University of Madrid, who measured how a group of individuals acted in the face of a common threat.

To do so they designed a "lab-in-the-field" experiment involving more than 320 individuals divided into 54 groups of 6 people. The experiment was conducted as follows. A total of 240 euros was given to each group of individuals. Each member of the group was given a specific amount of money. In half of the groups the 240 euros were divided evenly into 40 euros for each member. In the other half, the money was distributed unevenly in quantities from 20 to 60 euros. Over the course of ten rounds, each person then had to contribute to a common fund in order to reach a specific goal, namely 120 euros to be used in an activity against climate change, in this case planting trees in Collserola. The participants were allowed to keep any money that was left over. At the start of the experiment, each participant knew how much money the other had and at the end of each round they could see how much money each person had contributed.