A certain kind of society tends to produce a certain kind of person. More precisely, it discourages the development certain human capacities and fosters the development of others. Aristotle, Rousseau, Marx and Dewey were the philosophers who were most illuminating on this. They argued that the postures required by successful functioning in a market economy tend to insinuate themselves into those areas of social intercourse which take place outside of the realm of the market proper. The result, they claimed, was that the arena for potentially altruistic and sympathetic behavior shrinks over time as society is gradually transformed into a huge marketplace. (Later on I want to call in question the very concept of altruism.)
That study on blood donation was riveting. Capitalism is held to be the highest and most natural form of society because it "allows" us to behave in way that supposedly rewards behavior of rational and enlightened self-interest made in a free society. The author makes a compelling case for showing that this isn't really borne out by the way people behave when faced with a market economy. It actually limits our range of behavior and not in a way that benefits society.
I have to get ready to go out, I hope others will chime in too.