When my oldest child started preschool, I worried. I did not worry about whether #1 would learn science, letters, or numbers. I worried about friendships. Early childhood is a key period for developing the social skills required for lifelong friendships…and so I worried. A lot. If you think this fear was less when my second child started preschool, it was not. I worried again. Friendships are important for health and happiness throughout life – and knowing this, I couldn’t help but worry. Let’s begin with a discussion of why and how peer friendship are important in early childhood and end with a discussion of how parents can support their child in developing successful friendships.
Developmentally, young children can now walk around by themselves and have greater control over who they spend time with in social settings. Between 12 and 18-months of age, children begin to prefer spending time and interacting with some children more than others, waving at them more, smiling at them more, and engaging in more positive interactions (i.e., laughing at their potty jokes).  Around a year-and-a-half, children are more likely to initiate play with some children compared to others; moreover, children are more active and contribute more to play with their preferred peers compared to non-preferred peers.  Three and 4 year olds can make and maintain friendships and most children report at least one friendship. By the time children are 3-7 years old, the end of early childhood and the beginning of childhood, many children report having a “best friend” – and this best friendships is stable for at least a few months of time.
By the time a child is 2, he or she will have a growing arsenal of social skills including engaging in cooperative problem solving, taking turns during play, and learning and imitating just by watching a peer. These skills will continue to develop, as children gain more complex cooperation, pretend play, turn taking, and emotion sharing skills. Turns out that even in early childhood, friends bring out the best in us, with young children exhibiting these social skills more frequently with a friend than with an acquaintance. 
Of course, it’s not all sunshine and roses when it comes to early childhood friendships. Sure, children are more likely to cooperate and take turns with their friends, but they are also more likely to experience conflict. Partially, this is because friends spend more time with each other than nonfriends, but it is also true that the more complex play (and still developing social skills) means that there is bound to be more conflict. Remember, conflict isn’t a bad thing. Having conflict means that preschool children get a chance to learn how to resolve conflicts.
So how do preschoolers deal with conflict with a peer? It depends on if it is a friend or not. With a nonfriend, kids are most likely to talk to the other child or ignore the problem (e.g., quit thinking about it, walk away, or talk to somebody else). With a friend, children are most likely to talk directly to their friend. Are you reading this and freaking out because your child solves conflict in a more…direct…way?[a] Relax – your kid is normal for struggling to solve conflict with words. In fact, it doesn’t matter if it is a friend or not, preschoolers respond to peer conflict by yelling, kicking, or hitting about 10% of the time. Sometimes kids just get frustrated, and they are still learning to regulate that into appropriate ways.
Friendships are both the product of good social skills and an opportunity to continue to develop social skills. How do children select their friends in early childhood? For young children, proximity is the name of the game. Children form friendships with other children who they spend time with, either because they are neighbors or attend daycare or preschool together, or because their parents and the other child’s parents are close friends and so their children naturally spend a lot of time together. [b] Aside from proximity, young children are more likely to be friends with same-aged friends (this is because we separate children so much by age – if friends are from school or daycare, they are naturally going to be limited to a narrow age range) and sex. That is, boys with boys and girls with girls. This doesn’t mean that cross-sex friendships don’t exist, but they tend to be more fragile and to become more rare as children age (note that in adolescence, cross-sex friendships become more common again). Less is known about cross-race friendships in preschool, although in later ages, race and ethnicity will become factors in friendships.
So what do parents have to do with this process of friend making and social skill development? Evidence suggests parents and caregivers can be very influential. Most of the research has focused only on parents, so I will focus on that. First, children who have balanced, loving, positive interactions with their parents are inclined to interact with other children more willingly and to expect (and create) positive, balanced, reciprocal peer relationships. Specifically, infants who have a secure attachment with a parent (one that is based on trust and responsiveness) tend to be more confident, enthusiastic, emotionally positive – all things that make it easier for a child to attract peers to be friends. Indeed, children with a secure attachment have higher peer social skills, higher quality friendships, and are more popular with peers in preschool.
On the other side of the coin, children who have a rejecting or hostile relationships with their parents (called insecure attachment) are hypothesized to be hostile themselves and react to peers in a hostile and aggressive way. Turns out, there is some evidence for this. Toddlers and infants who were insecure attached tend to be more aggressive, whiny, or socially withdrawn.
The relationship between the parent and infant can influence early childhood peer relationships, but it’s not like you only have to have a good relationship in infancy and then you are good to go (Later kiddo! Mom worked really hard for your first 12 months and now I am out!). Throughout early childhood, children who have moms who are warm, discuss emotions, and use positive verbalizations are simultaneously more popular with peers.  The same is true for child-father relationships. 
Beyond the quality of the parent-child relationship, there are two ways parents and caregivers can help a child succeed in peer relationships in early childhood. First, parents (and caregivers) are gatekeepers – they have to provide opportunities for their children to spend time with peers. Parents who arrange and oversee opportunities with peers tend to have children who are more positive and social with peers, have more socially skilled peer interactions (assuming the parents aren’t overbearing). In other words, parents who provide lots of positive opportunities for their preschooler to play with other children have preschoolers who know how to play well with other children.  Practice, it turns out, makes progress in social skill development.
The second factor is appropriate coaching child behaviorally and emotionally. For instance, skilled caregivers will make suggestions about what to say, who to approach and who not, and how to appropriately play. Skilled caregivers also help explain what is an appropriate emotional reaction and how to deal with it.  Imagine a 3 year old arriving at a playground with her nanny. The nanny may help the child approach a group of other children in the sandbox (“Say hi to the other children!”) and may help the child cope with stress (“Oh he can take a turn with that truck. No need to cry. Why don’t you trade trucks for a few minutes and then trade them back?”). These coaching efforts develop skills that a child can use later (i.e., how to approach a group or how to share) even when there is not a parent or caregiver around.
Let me point out something that may not be obvious though: successful coaching means letting the child try and make mistakes. You will not be present at some point and your child will have to do it all on his or her own. Your job is to set them up for success. A child can be over coached and micromanaged in peer interactions, and that isn’t helpful. Failure is just as important. Your kid has to figure it out, your job is to nudge him or her along successfully – enough nudging to generate success, but enough flexibility to allow the child to make mistakes. This doesn’t mean you can’t talk about mistakes and offer suggestions for next time. But keep it simple, short, and wait until your child is unemotional.
Making friendships and developing social skills is critical in early childhood. As a parent, you can help by being warm, empathetic, talking about emotions, and helping your child develop social skills. Providing opportunity and coaching to your child, while giving them sufficient independence, can set them up for success for a lifetime of rich friendships well beyond early childhood. You’ll still worry. But you’ll know you are doing what is best for them.
[b] Remember parents, you can pick your friends, but you can’t pick your friend’s kids.
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