The University of Notre Dame's Science of Generosity Initiative has performed many experiements investigating generosity as a character trait. One study showed that there are some genetic predispositions that influence one's tendency to give. In addition, one researcher found that "talking with children about giving raises the probability of their giving by 18.5 percent over not talking to them about it."
Introduce your children to social issues, such as poverty or clean water, that are important to you and read books together about the issue. There are many children's books on social issues - just search the internet for the topic of interest to you. Consider spending one day without using your tap water or miss one meal to teach your children what life is like in other countries / communities.
During family mealtimes include discussions of how you choose to spend your money. If you give to charities, let your children know - and tell them how happy it makes you to be able to help others. If the charity is local, consider visiting with your children so they can better understand how money is being used.
Consider choosing a social issue or charity for the family to help. Brainstorm together, thinking of ways your family can help. Children are so creative - but consider the following.
This is a great opportunity for children to develop initiative, creativity, responsibility, and persistence as well as generosity - depending upon the project chosen.
Think of other ways besides money by which you can impact the lives of others, such as the following.
When you see your child being generous - specifcally praise the behavior. "I so enjoyed seeing you share your new game with your brother."
Don't provide rewards when children demonstrate generosity. Their sense of well being is their reward.
People have varied opinions regarding the desirability of giving children an allowance, but providing children with a small amount of money allows you to teach them financial principles, including generosity.
Consider providing your child with three "banks" or jars or envelopes. Show him that every time he earns or receives money, he should divide the money into three portions - one for him to be able to use, one for him to save for sornething (teaching delayed gratification), and one to be used to help others (teaching compassion and generosity).