Two moms are at the park watching their preschoolers play. One child hands a toy truck to his friend and says, “Here, you can play with it.” The other hangs on to his toy car for dear life. When his friend asks to share it, he stubbornly says, “No! It’s mine!” and jerks his hands away.

What accounts for such different reactions? Are genetics involved?

One could certainly argue that we see both selfishness and cooperation in all people including these preschoolers. The age old conundrum: are humans innately selfish or goodhearted is still debated around dinner tables. Selfishness and generosity wax and wane in all of us. In some more than others. There are times we cooperate for the common good and other times, not so much.

Over forty years ago, Richard Dawkins published his book, The Selfish Gene, asserting that yes, we are innately selfish. Efforts to understand this nature/nurture question are complicated. Answers are often sought through research with animals and even bacteria.  In more recent studies with identical twins, genetics do seem to be involved in sharing. In fact, a gene has been identified that is linked to altruistic behavior. The gene, AVPR1A, regulates a hormone in the brain associated with social behaviors like sharing. A variant of this gene is associated with increased selfishness. But remember, no behavior is completely caused by your DNA. Even Dawkins noted that genes do not live in isolation. Environment, learning, school, parenting and so much more, influence how behaviors are expressed. And certainly a transformed life can turn selfishness into altruism.

Altruism, or sharing, seems to be more influenced by environment. Positive reinforcement of sharing and altruistic behaviors help teach these traits to children. Generosity can be habit forming and learned. It engages the reward circuits of the brain and releases feel-good transmitters. And we know that generosity can grow as children mature and develop stronger ideas of morality and fairness.

If you want to encourage less selfishness, try these suggestions:

1) Encourage sharing and activities that benefit others. The more we talk about the importance of cooperation and sharing, the more we encourage it.

2) When someone shares, praise the behavior. This is how you reinforce children toward more cooperation. Praise a child or an adult’s behavior when it involves sharing, cooperation and generosity.

3) Talk about how people feel in order to teach empathy and sharing. Sharing brings on a good feeling, that warm glow as some call it. The feeling itself can be reinforcing.

4) Discuss consequences of behavior when a person is selfish. Ask questions like, how does the other person feel when you are selfish? Do others want to be around you? Will you be liked as a selfish person? Will this help your relationships and your job?

5) Model sharing and concern for others. Be generous and giving. Show others and be a light.