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The Science of Generosity

Would you help this child?

I just finished reading Theodore Malloch's wonderful new book Being Generous (Templeton Press, 2009) that investigates the reasons for and results of generosity. The book draws on a variety of evidence to show that generosity is not only good for society, but good for the individual. Throughout this inspiring book, pithy and interesting one page biographies appear of well-known givers and their motivations for helping others. These range from Johann Sebastian Bach, John D. Rockefeller, and Mother Theresa to Bill and Melinda Gates.

Giving USA reports that in 2005, individuals in the US gave $199 billion dollars to charity. In the same year, 65 million Americans spent an average of 50 hours volunteering to help others. Using the average US hourly wage, this constitutes an additional charitable donation valued at $60 billion. While this pales in comparison to the federal deficit, $259 billion is a big chunk of change. Could science explain this extraordinary generosity?

My lab has been investigating the biological basis for generosity, focusing on the neuroactive hormone oxytocin. We were specifically interested in generosity, or "liberality in giving," rather than people simply giving small gifts to others. Many people have an urge to give just a bit, but we wanted to know why someone would ever give more than they had to. We used a task called the Ultimatum Game in which people are randomly and anonymously paired by computer in a large lab. After extensive instruction and without a speck of deception, people are endowed with a sum of money like $40 and then asked to propose a split of this money to the other person in their pair. No communication before or after the proposal is allowed. The receiver then decides if s/he wants to accept the proposal or reject it. If accepted, the money is paid privately to each person and the experiment ends. But, if the proposal is rejected, both individuals earn nothing.

How much would you offer as a split? In Western countries, offers less than 30% of the endowment are nearly always rejected. Why? Easy--it is simply unfair. We turned this question on its head: why would anyone offer more than one needs to have the offer accepted? We did this by having each person make decisions both as proposer and to identify their smallest acceptable offer as responder. Later, we randomized which role they would actually play and this determined their earnings. Generosity is the difference between what one offers and the smallest amount one is willing to accept.

I had a hunch that oxytocin, which I had already shown causes us to trust others as I discussed in a recent article in Scientific American would also make people generous. So, we infused 40IU oxytocin into half the participants using a nasal spray, and similarly administered salt water to the other half, without them knowing which one they had gotten. They then made decisions in the Ultimatum Game. In a 2007 publication, my team reported that oxytocin increased generosity by 80% compared to the placebo group.

This was a huge effect in an experiment where we tormented people by putting two teaspoons of liquid up their noses. The next question was why oxytocin caused generosity.

Giving to others is often prompted by understanding their perspective. How would you feel if you lost your house to a hurricane or fire, or found yourself homeless after looking for work for a year. We can image how awful these situations would be and this motivates us to help others. Shortly after the August 2005 hurricane Katrina disaster I asked my lab who had donated money to the relief efforts. Several students raised their hands and when I asked them why, most related highly emotional stories of suffering they had seen on TV. The stories were often so emotion-laden that their eyes teared up on the telling.

This gave me and my graduate student Jorge Barraza an idea to run an experiment that simulated this effect. We had participants watch one of two 100 second videos. Both videos feature a father with his four year old son. The son is bald from chemotherapy due to his terminal brain cancer. In the emotional video, the father discussion how it feels to know his son is dying. In the neutral video, the father and son are having a day at the zoo and cancer and death are not mentioned. You can see the video in an earlier PT Blog I wrote. I showed the emotional video recently to group of lawyers at a conference and one-third of them cried so much I had to stop my lecture. If it makes lawyers cry, you know that regular humans are really affected by it.

We drew blood before and after people watched one of the two videos and found that doing nothing more watching the emotional video produced a huge 157% spike in oxytocin levels. Oxytocin levels actually fell for those who watched the neutral video. We then asked people how they felt after seeing the videos. For the emotional video, the change in oxytocin was correlated with feelings of empathy (after we controlled for the distress people reported that correlated with the stress hormone cortisol). Oxytocin connects us to others and lets us understand their emotions.

The most amazing part was that after the videos people made decisions in the Ultimatum Game so we could see if empathic engagement would make people more generous towards another person in the lab. It did. Generosity towards another meant that the giver earned less money for his or her participation in this long and unpleasant experiment.

As participants were leaving the experiment, we also gave them a chance to donate some of their earnings to charity. One-third of the participants did so, averaging a six dollar donation (this was about one-quarter of the average earnings). Who donated? Those who were the most generous and most empathically engaged by the video.

It may very well be the case that those profiled in Being Generous release more oxytocin than others and this partially explains their generosity. Oxytocin connects us to others and social connections are a powerful way to increase one's own happiness. If you want to connect to others, being generous is a great start. You can follow Malloch in this--he is donating all book royalties to the charity portal Global Giving. If you would like to choose a project to donate to, go to You just might feel the joy of generosity.

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