One of the most common objections to market-based societies is that they erode non-market motivations to doing good. Critics, with this objection, say that although markets can in some areas latch onto greed and turn it to society's benefit in some areas ("It is not from the benevolence of the butcher, the brewer, or the baker, that we can expect our dinner, but from their regard to their own interest") they can also pervert and corrupt existing motivations in domains where markets are inappropriate. Consider blood donations: many argue that if you start paying for blood donations then people will stop seeing them as a good deed but as a market activity, and lose their 'intrinsic motivation' to give blood. Overall you might get less blood, or less good blood than before, even though you're now spending money to get it. Back in 2012, Harvard communitarian political philosopher Michael Sandel (famous for his online lectures), wrote a hugely popular book What Money Can't Buy: The Moral Limits of Markets making roughly these arguments (read a wonderful review here).

These questions are discussed widely, but what's weird is they tend to be tackled mainly with a priori thought experiment arguments like mine about blood, above, and anecdotes, even though they are empirical questions. We can actually test whether you get less or worse blood when you pay for it! (You don't) We can test whether people are less pro-social when you add extra market institutions!

A new paper by Björn Bartling, Roberto Weber and Lan Yao, "Do Markets Erode Social Responsibility?", in the Quarterly Journal of Economics tries to do as much:

This paper studies whether concerns for social responsibility persist in repeated market interaction. We develop a laboratory product market, in which socially responsible behavior by firms and consumers involves incurring additional production costs to mitigate potential negative externalities imposed on individuals otherwise uninvolved with the market.

The data from Study 1, conducted in Switzerland, show, first, that there is a non-trivial share of socially responsible products supplied and demanded in all our market conditions, and that—importantly—the market share of the fair product is stable over time in all conditions.

Second, the socially responsible product, which costs more to produce, sells at a price premium that persists with market experience. In most cases, this price premium increases over time, suggesting that consumers’ willingness to pay for socially responsible products is not eliminated with repeated market interaction. Third, we show that individual-level market behavior is consistent with a preference for positive social impact, though such concerns are heterogeneous.

In other words: markets do not erode existing pro-social motivation; they complement it.