Thomas Hobbes’s social contract may seem a long way from the fraught issue of how unpaid water charges will be handled. Yet, it’s right at the heart of the dilemma facing us. When groups try to organise their lives collectively, the first job is to agree a social contract: what contribution is needed from each member to make the group work effectively? This contribution inevitably involves a sacrifice with no immediate benefit to the individual. But it is made on the assumption that it will increase the benefit to the whole group and, in time, to each individual.

I’m going to describe a series of classic psychological experiments by behavioural economists on how a social contract works, and what destroys it. The results are stark. They lay bare the long-term risks of the wrong decision about unpaid water charges. Perhaps even more importantly, they also reveal the long- term political and civic benefits of getting it right.

Experiments

Here’s how the experiments worked. Participants were divided into multiple groups. In each group, each person was given the same amount of money and was given a choice. They could either keep the money for themselves, or make a contribution to a common pot that the experimenter would then double and distribute to be shared by the group. So there was an incentive to contribute to the common good. Of course, somebody who contributed could only benefit if everybody else did the same. That was the risk. So the whole process depended on trust and co-operation.

We know from many previous studies that, in any group, there are usually many people who are initially willing to co-operate. There is also a sizable minority of people who will only co-operate as long as they are assured that others also will. And, of course, there are always some people who are tempted not to co-operate at all.

In the first round of the experiment, most people contributed substantially, giving between 40-60 per cent of their money to the common pot. Although each contribution was anonymous, as soon as the pot was counted, it became clear to those that had contributed a lot that others had contributed less or not at all.

But here’s the really interesting twist. After a few rounds, some groups were given the option of imposing sanctions on those who had not co-operated. Other groups were not given this option. And here’s what happened.

In the groups where people were not given the option of imposing sanctions, in the subsequent rounds, group contributions dropped quickly and significantly. By the last round, three-quarters of the group were contributing nothing and the remaining quarter next to nothing. Effectively, group co-operation had collapsed.

In contrast, in the groups where those who refused to contribute were sanctioned, everybody contributed substantially more in the subsequent rounds. In fact, people contributed between two and four times more than in the of group where there were no sanctions. Even those who had initially not co-operated increased their contribution by between 50-60 per cent. Round after round, average contributions of between 50-95 per cent were maintained. Moreover, when the group was given the chance to agree on a common standard, the group contribution reached almost 100 per cent – a microcosm of what a well functioning, co-operative generous society should look like.

Unfairness rankles

These experiments were replicated with many groups, many times, with the same findings. The first lesson is clear. People will not passively accept a situation where others are not contributing fairly or at all, while continuing to reap the benefits. Unfairness rankles deeply with people. Nobody wants to be a sucker.

In the experiments, when the participants were asked how they felt about those who refuse to contribute, they scored six on a seven-point anger scale. Understandably, those who contributed a lot expressed the most anger. But, even those who had contributed relatively little were also angry with those who had refused to contribute at all.

What these experiments showed is that people are more than willing to sanction those who do not co-operate in a group, even when it brings no personal benefit to themselves, or actually costs them something. So if they are not doing it to further their own interests, why are they doing it? Because people appear to be instinctively motivated to protect others in the group against what they see as the kind of rank unfairness that destroys group solidarity. Interestingly, MRI studies of people engaged in sanctioning unfairness show increased activity in the pleasure centre of the brain. In other words, the brain works in such a way that maintaining social order and the rules of fairness is its own reward.

People are motivated to create good societies for all kinds of positive reasons. But as Nobel laureate Daniel Kahneman observes: “Altruistic punishment could be the glue that holds societies together.”

The implications for the issue of water charges hardly need to be spelt out. If Irish politicians want to build the kind of high-trust society where civic co-operation is high, and people are willing to contribute generously to the common good, then the right, although politically troublesome option, is for unpaid water charges to be pursued. There appears to be little appetite to do that in any political party. The only other, but deeply imperfect, option is to refund those who did pay. If that does not happen, there probably won’t be noisy protests on the streets. But, as these careful behavioural experiments show, the damage will be silent and insidious: the further disintegration of an already low public trust in politics and political parties in Ireland. In an increasingly politically unpredictable world, that is a big price to pay. Cui bono?

Dr Maureen Gaffney is a psychologist and author of Flourishing (Penguin)