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Joining a group diverts regret and responsibility away from the individual

Cite this dataset

El Zein, Marwa; Bahrami, Bahador (2020). Joining a group diverts regret and responsibility away from the individual [Dataset]. Dryad.


It has recently been proposed that a key motivation for joining groups is the protection from negative consequences of undesirable outcomes. To test this claim we investigated how experienced outcomes triggering loss and regret impacted people’s tendency to decide alone or join a group, and how decisions differed when voluntarily made alone vs in group. Replicated across two experiments, participants (N=125 and N=496) selected whether to play alone or contribute their vote to a group decision. Next, they chose between two lotteries with different probabilities of winning and losing. The higher the negative outcome, the more participants switched from deciding alone to with others.  When joining a group to choose the lottery, choices were less driven by outcome and regret anticipation. Moreover, negative outcomes experienced alone, not part of a group vote, led to worse subsequent choices than positive outcomes. These results suggest that the protective shield of the collective reduces the influence of negative emotions that may help individuals re-evaluate past choices.


The data was collected online on Amazon Mechanical Turk and Prolific. It was processed and analyzed using Matlab and R. 

Usage notes

Experiments 1 and 2 are included in the main text. Experiment 2b is an older version of Experiment 2: in this version, because of a an error in the experiment code, only half of the total of 48 lottery choices were shown to participants.

Description of the variables in the open data sheets:

Sub: subject number.

Age: subject’s age.

Gender: subject’s gender.

Proportion play alone: proportion of trials the subject chose to play alone.

Gamble resp: Choice of Lottery 1 (1) or Lottery 2 (0).

EV: Difference in expected value between Lottery 1 and Lottery 2.

AR: Difference in anticipated regret between Lottery 1 and Lottery 2.

Group resp/current condition: Choice to play alone (0) or as a group (1).

Experienced outcome: Obtained – Unobtained outcome from the previous round.

Previous condition: Previous round played alone (1) or in group (2).

Group status: Previous round in group majority (1) or minority (2). 0 corresponds to previous rounds played alone.


Wellcome Trust, Award: 204702

European Research Council, Award: 309865

European Research Council, Award: 819040