DOI: 10.5061/dryad.5qfttdz2t
title: Timing uncertainty in collective risk dilemmas encourages group reciprocation and polarization

description: Social dilemmas are often shaped by actions involving uncertain returns
 only achievable in the future, such as climate action or voluntary
 vaccination. In this context, uncertainty may produce non-trivial effects.
 Here, we assess experimentally — through a collective risk dilemma — the
 effect of timing uncertainty, i.e. how uncertainty about when a target
 needs to be reached affects the participants’ behaviours. We show that
 timing uncertainty prompts not only early generosity but also polarised
 outcomes, where participants’ total contributions are distributed
 unevenly. Furthermore, analysing participants’ behaviour under timing
 uncertainty reveals an increase in reciprocal strategies. A data-driven
 game-theoretical model captures the self-organizing dynamics underpinning
 these behavioural patterns. Timing uncertainty thus casts a shadow on the
 future that leads participants to respond early, while reciprocal
 strategies appear to be important for group success. Yet, the same
 uncertainty also leads to inequity and polarisation, necessitating the
 inclusion of new incentives handling these societal issues. 
description: The data was collected through behavioral economic experiments
 performed in a laboratory. Participants remain anonymous throughout the
 experiment and interact with other through a tablet computer. The
 experiment was divided into a control and 2 treatments. The control
 (treatment 1 - NU) uses a similar setting to Milinski et al. 2008, where
 participants play a collective risk dilemma (CRD) with 90% of risk and 10
 rounds. Participants interact in groups of 6 subjects to which they are
 randomly assigned before the experiment starts. Jointly they are required
 to contribute to a public account from their endowment (40 EMUs) to
 achieve a total of 120 EMUs by the end of the experiment. If they achieve
 or surpass this value, participants keep in their account whatever was not
 contributed, otherwise their final payoff will be 0 EMUs with 90% of
 probability. The 2 treatments test two levels of timing
 uncertainty. In treatment 2 (LU) the setting remains the same, but the
 total number of rounds is uncertain. Participants know that the game has
 at least 8 rounds, on average 10 and that after round 7 there is 1/3 of
 chances that the experiment will end in the next round. In this way, at
 the end of round 8 (and all other rounds that may follow) a virtual dice
 with 6 faces is thrown and if the results is either 1 or 2 the experiment
 ends. Treatment 3 (HU) has the same design, with a
 change in the variation of the distribution that defines the duration of
 the experiment. In this treatment the experiment takes at least 6 rounds
 and after round 5 there is 1/5 chances that the experiment will end in the
 next round. In this case, at the end of round 6 (and all the other rounds
 that may follow) a virtual dice with 10 faces is thrown and, if the result
 is 1 or 2 the experiment ends.
description: Please refer to the file "Readme.md" for information on
 the meaning of each feature (column) in the dataset.