When fairness is not enough: Study reveals why individuals may need to contribute more than their ‘fair share’ to the common good

A behavioural experiment led by researchers from the University of Warwick and University College London has revealed how poorer people are willing to contribute disproportionately more to the common good than the rich - but what people judge to be a ‘fair’ contribution overall may not be enough to solve collective problems.

The researchers recruited 240 participants to take part in a collective action game to investigate how inequalities, and different causes of inequalities, impact people's behaviour in a situation where individual interests conflict with group goals. The game is known as the ‘collective-risk social dilemma’ and is designed to represent the dynamics of international climate change negotiations.

Participants were randomly assigned to groups of four made up of two ‘richer’ individuals who were each given £20 and two ‘poorer’ individuals who were given £10. Groups were assigned to one of three treatments: in the merit treatment, participants’ wealth was determined by their performance in a task; in the luck treatment it was determined by a lottery; and in the uncertain treatment it was determined by either merit or luck (participants did not know which).

Players then had to decide how much of their fund to contribute towards a group target of £30 in 10 successive rounds. If they achieved the target together and had £30 in the group pot by the end of the 10th round, they were each able to take home any money they had leftover. But if the group failed to achieve the target, players faced the prospect of losing their remaining funds.

The researchers observed that what people judged to be a fair contribution was not enough to meet the target: if they acted according to what they thought was fair, they would fail as a group. The level of an individual’s wealth also influenced what they judged to be a fair contribution towards the group target, but the cause of their wealth did not.

When it came to contributions within the game, poorer individuals consistently contributed a higher proportion of their wealth (40.4% on average) than richer participants (37.5% on average), which further increased inequality within groups – particularly successful ones. This was true across all three treatments, indicating that the poor contributed disproportionately more regardless of the cause of wealth.

The researchers highlight that the findings are relevant to many real-world societal challenges, where what is judged to be a fair contribution at an individual level may ultimately be insufficient to overcome the problem.

Professor Daniel Sgroi said: “Many of society’s most pressing challenges, from combating climate change to dealing with pandemics, are collective action problems: situations in which individual and collective interests conflict with each other.”

“For example, since the Paris Agreement countries have outlined national targets to contribute to the reduction of global emissions, but they fall far short of the estimated 45% reduction required to limit global warming to 1.5°C. Similarly, individuals may face a dilemma about whether to alter their own behaviours to reduce emissions – weighing up the benefits to the common good with factors such as convenience and cost. Understanding which factors influence people’s willingness to make contributions is vital for the design of policies that support the attainment of collective goals.”

Read the full paper

‘When Fairness is Not Enough: The Disproportionate Contributions of the Poor in a Collective Action Problem’, by Eugene Malthouse, Charlie Pilgrim, Thomas Hills, and Daniel Sgroi is forthcoming in the Journal of Experimental Psychology. It is currently available as an Institute of Labor Economics discussion paper.

The paper is the first in a series that now involves more than 70 researchers across 37 countries. The series aims to explore the effect of different types of inequality in collective action problems.

Daniel Sgroi is Professor of Economics at Warwick. View his staff profile.