Your baby's every interaction is teaching her about relationships. Babies are biologically hardwired to engage with other people and take something away from the experience. There are milestones you should look for as signs that your child is on her way to being a great friend.
At six weeks your baby will beam at you. Within 72 hours of being born, mirror neurons in the brain prompt infants to mimic the facial expressions they see. By six to eight weeks babies have developed the combination of visual acuity and brain development to give a true "I know you smile." Social smiles are your baby's response to the world around him. Make sure you're giving him reason to grin by blowing raspberries and breaking out go-goo noises.
At three months your baby adores your face. Evolution may have programmed him to love gazing at you because you're the key to the care he needs to survive. Babies also know faces are social. Studies have shown that when babies look at pictures they often reach out as if to say "Why aren't you talking to me." They expect a voice to come with a face. Make sure you're making all kinds of faces at your baby - eyebrows up, lips puckered. Once your baby has mastered your face, he'll realize that other people have eyes and noses too.
At six months your baby is anxious around new people. Wariness indicates cognitive growth and can last until a baby is a year old. Your baby can now distinguish grandma from your friend. It also means he grasps permanence, the concept that you exist even when she can't see you. When your baby is around new people, give him a chance to warm up. If you're going on a date night, pay the sitter to come a little earlier so that she can break the ice with your baby.
At twelve months your baby hands you the car keys. The potential motive behind your toddler bringing you random items from around the house is something like "I want you to know that I find this interesting. Can you tell me what these are?" As babies get more mobile, count on them to do a lot of this. Recognize that these moments are your baby's first attempts at conversation. Say, "Oh you found my house keys. Can we put them in the lock?" This response boosts your baby's vocabulary and teaches her that what's important to her is important to you.
At eighteen months your baby will offer comfort. At this stage, kids not only notice when others are in distress, they also have the desire to help. Show compassion. When you cuddle and soothe your toddler, you're teaching him how to respond to someone else's sadness. Don't be surprised if he soon notices when you're bummed out and offers you a smooch.
For more information on milestones for your baby and other parenting tips, click here.