The economic theory of public goods makes a very clear prediction. The prediction is that if the benefits of some action go to strangers, not to yourself, then you won't do that action. Economists have run dozens of experiments testing out this prediction. A typical "public goods game" is quite simple. Everyone in the experiment is given, say, $5 each, which is theirs to take home if they like. The experimenter tells everyone that if they donate their money to the common pool, all the money in the pool will then be doubled. The money in the pool will then be divided equally among all players, whether they contributed to the pool or not. That's the whole game