Let's start by choosing a better word than tattling. Tattling has such negative connotations that the word doesn't accurately reflect what a child may be trying to tell us. Instead of tattling, let's call it telling.
There are many reasons why a child may tell us about another's behaviour. A very young child (2.5 to 4) is most likely frustrated and asking us for help in a difficult social situation. At this age, children are still learning their language and often need an adult's help in conflict resolution.
An older child may be showing leadership by reporting that another is not following the classroom or household rules or she may be checking if the rules have been changed. All parents and teachers allow for a certain amount of negotiation and some older children will constantly check to see if a rule has been bent or changed. They are not usually trying to get the other child in trouble. Rather, they are asking for clarification in a situation that seems to go against their understanding of fairness and justice.
Older children also tell in a show of responsibility. "Tommy is drawing in his math book. I told him not to but he won't stop!" There is an enormous sense of community in this kind of telling. The rules are clear to this child and she did try to do something about it. This kind of telling indicates that a child may be ready for more responsibility. Instead of condeming the child for tattling, the adult in this situation could help the child figure out the next step. Helping the older child to project future consequences by posing some carefully worded questions is far more helpful than sending her away with a quick "Go back to work and mind your own business! "
Then there is the telling that is the product of an adult always stepping in to "solve" a disagreement. "She's looking at me!" or "He stepped on my backpack!" At moments like this, it behooves the adult to remove themselves from the conflict expressing confidence in the child's ability to take care of herself. By settling every conflict, adults inadvertently make matter worse and take away opportunities for children to learn how to resolve their own conflicts. In the case of sibling rivalry, adults need to be very careful that they are not showing the children how profitable it can be to fight ( Dreikurs, 1964).
Often, we are told that a child tells just to seek attention. While I don't totally disagree with this statement, I do think it needs to be fleshed out. Of course a child tells to get our attention. If they could sort out the situation by themselves, they wouldn't need to solicit our help/attention. If a three year old comes to me and says "Tommy's touching my work." that child is really telling me that she doesn't know what to do next (short of clobbering Tommy). She must have my attention in order to move forward in her acquisition of the language of social disagreement. The older child must have my attention because something has disturbed her sense of fairness and justice. It is our job as facilitators and parents not to arbitrate but to help them find peaceful ways to develop diplomacy and respect for each other (Dreikurs, 1964).
If we view telling from the perspective of natural and logical consequences, keeping child development firmly in our minds, we can much more effectively assist children to move from telling all the time toward developing the skills needed to deal with conflict.
Dreikurs, R. and Soltz, V. (1964). Children: the challenge. Markham, Ont.: Fitzhenry & Whiteside.