When asked why, many say, "I don't have enough money to spare." But it's telling that the working poor manage to give.
And the rich? What about America's 400 billionaires? I'll report on them in next week's column.
Finally, Brooks says one thing stands out as the biggest predictor of whether someone will be charitable: "their religious participation." Religious people are more likely to give to charity, and when they give, they give more money -- four times as much.
But doesn't that giving just stay within the religion?
"No," says Brooks, "Religious Americans are more likely to give to every kind of cause and charity, including explicitly nonreligious charities. Religious people give more blood; religious people give more to homeless people on the street."
And what happened in our little test? Well, even though people in Sioux Falls make, on average, half as much money as people in San Francisco, and even though the San Francisco location was much busier -- three times as many people were within reach of the bucket -- by the end of the second day, the Sioux Falls bucket held twice as much money.
Another myth bites the dust.