Every child’s temperament is unique. Some kids hit, bite, and don’t share toys; and some kids are naturally social, friendly and sensitive to others. No matter what a child’s natural tendencies, every child is capable of kindness.

There are lots of great ways to develop kids’ kindness, but the most important thing to know is what a child is developmentally ready for. You can’t expect a baby to know it’s unkind to repeatedly throw mom’s keys on the floor just to watch her pick them up. Children develop their capacity for empathy in stages. Here’s where to focus your effort at each stage:

Toddlers: Don’t tell them to be nice

Expecting empathy from a toddler is pointless. You can explain that it isn’t nice to grab a toy out of a friend’s hand, and Molly might not do it again if she thinks not grabbing is a family rule. But she certainly isn’t going to understand the key concept of being “nice.” Toddlers’ brains simply aren’t wired to understand another person’s point of view. That’s why the little stinker thinks you can’t see her when she hides under a tablecloth, even though her bottom is sticking out. Toddlers haven’t physically developed the brain wiring that allows them to see the world from another person’s perspective. If they can’t see you, they are sure you can’t see them. (This explains why Peekaboo is more fun with a toddler than a teen.)

So guide your toddler to kindness by giving concrete instructions. For example, you can’t tell a toddler to be nice. She has no idea what that means. At this stage, you can model kind actions by saying “this is how we are nice” anytime you are helping her to be kind.

4-7 year olds: Be kind and they’ll pass it on

As kids approach kindergarten they establish their personal identity. They finally discover we are separate people with distinct perspectives and feelings. You can confirm that a child has reached this stage when they want to play cooperative games with other children. For example, your child will create more complex imaginative play and say, “you be the teacher and I’ll be the student” once they begin to understand the world can be seen from a variety of roles.

Parents can make the biggest impact by modeling kindness during these early elementary school years. Just as young kids learn language by mimicking their parents’ speech, older kids learn how to behave towards other people through imitation. Let your kids observe you being kind and they will be kind too. And show them small kindnesses. Instead of jumping to clean up a glass of milk he accidentally spilled, give your son a hug and a little extra attention and say something sympathetic. I guarantee you’ll catch him trying to make his buddy feel better after he strikes out at T-ball.

8 and up: Kindness comes from practice

Once friends start to become as important as family, kids need the opportunity to practice being kind. There are lots of great tips for kids this age and this is a great stage to discuss charity projects and start volunteer activities. But the most surprising and effective way to develop kindness at this age is through books. Reading literary fiction teaches empathy. Stories that focus on characters and their relationships inspire readers to imagine the character’s intentions and thoughts. A series of studies by a social psychologist at The New School in New York City found that reading popular fiction, such as action books and other stories set in alternative universes have predictable characters and don’t develop empathy. But literary fiction improves a child’s ability to understand what others are thinking and feeling -- an essential component to developing kindness.

The best part about teaching our kids to be kind is that we get to be kind in the process and that feels good. Plus, you’re totally justified to curl up with a good book and call it parenting research!