The results of their research suggest that Americans’ attitudes toward giving have changed, regardless how much money they have. There is some research suggesting that poor people—those would actually stand to benefit from charity themselves—are more likely to donate money (overall, wealthy Americans still contribute most of the country’s charitable dollars). An analysis by the Chronicle of Philanthropy found that wealthier Americans gave less of their income to charity during the Recession, while the poor gave more. Those who earned $200,000 or more gave nearly 5 percent less to charity in 2012 compared to 2006, while those who made less than $100,000 increased their giving by 5 percent between those same two years, the report found. The poorest Americans—those earning $25,000 or less—increased their giving the most, by 17 percent over the same period. This study, while revealing, is limited to data gleaned from tax records in which charitable donations were listed as itemized deductions, something wealthier individuals are more likely to do, Meer says. That means that, while interesting, the sample is hardly representative of the entire country.

Even so, a more recent survey from sociologists at the University of Notre Dame echoes these findings. In their book, American Generosity: Who Gives and Why, they asked nearly 2,000 people about their views and habits regarding charitable giving. They found that Americans living below the poverty line were slightly more likely than others to give more than 10 percent of their income to charity. But as Meer’s new research shows, even a person’s income or wealth can’t explain all of the decline in charitable giving during the Great Recession. There is another possible explanation, and that is growing cynicism. Fewer Americans feel that their volunteer work and donations actually make a difference in their communities.

Though Meer’s research provides no concrete answers to why this shift is happening, it helps to highlight what motivates people to give in the first place. It was long assumed that people donated money to charity out of pure altruism, meaning that donors wanted to contribute to the public good and expected nothing in return. Then in 1990, research by economist James Andreoni coined the term “impure altruism,” also known as “warm-glow giving.” In his study, Andreoni linked motivations for charitable giving to more selfish origins, such as social pressure, sympathy, guilt, or the desire to earn prestige and respect. More recently, neuroscientists have discovered that acts of charity give humans pleasure, activating two parts of the brain: the ventral tegmental area in the midbrain that gets satisfaction from sex, drugs, and food, and the subgenual area of the brain, which is stimulated in response to cute babies and romantic partners.