Little kids like to help out. An easy way to engage a toddler in play is to start to work on something and make it look like you need help. Often, they will come over immediately and work to help you with whatever you are doing.
The psychologist Michael Tomasello has gotten interested in what makes young kids want to be helpful. There are three explanations that he addresses across two sets of studies.
One possibility is that children learn to be helpful, because they are rewarded for their helpful behavior. A second possibility is that children enjoy being helpful to others, and so they help others to experience that positive feeling. A third possibility is that children are motivated to want people who need to get help to get help, whether they provide that help or not.
In one study by Felix Warneken and Michael Tomasello, published in 2008 in Developmental Psychology, they gave young children (around 20 months of age) the opportunity to help an experimenter who dropped an object. For helping, some children were given a reward. Others were praised. A third group was not given a reward or praise. Then, children were given a chance to be helpful again. Children who received a reward were much less likely to help again than those who were praised or received no reward.
This finding suggests that children help because there is something about being helpful that they enjoy. When they are given a reward, it undermines this intrinsic enjoyment of being helpful.
A second study by Robert Hepach, Amrisha Vais and Michael Tomasello in the September, 2012 issue of Psychological Science explored exactly what it is that children enjoy. This study took advantage of the observation that when people are involved in a situation, the pupils of their eyes dilate. So, pupil size can be used as a measure of involvement.
In this study, the children were 22-month-olds. The children saw an adult sitting in a small model house sitting at a table. Then, they were taken outside the house and they looked in the window. The window was actually a computer monitor showing the adult trying to build a tower. At the end, they were trying to pick up a block that was out of reach. While they watched the monitor, their pupils were measured. In general, children's pupils dilate because they want to help the adult.
Now, the children were brought back into the house by their parents. Some children were allowed to help the adult (which they did). Some children watched as a second adult helped the first adult reach the block. A third group was held by their parents and not allowed to help.
Afterward, the children watched an unrelated video on the computer monitor and their pupils were measured again. The children who helped and the children who saw another adult help both had smaller pupils than the children who were not allowed to help. That is, the children who were not allowed to help were still concerned that the adult in the house needed help. The other two groups of children were content that the adult had been helped, whether or not they were the one who did the helping.
Putting all this together, then, young children seem to get enjoyment out of seeing others get help. When possible, they will try to help themselves, but it seems to be enough that someone helps. From these studies alone, it is not clear whether this desire to help is innate, or whether children learn this helpfulness from observing others in their first two years of life.
Of course, if you are the parent of a teenager, the real question is, "What happens to that intrinsic enjoyment of being helpful?"