Socialization refers to the process of developing social and emotional skills across the lifespan and is a process through generations. In this process, people develop beliefs (1) behaviours (2), values (3) and norms (4) that are appropriate in society. It is essential for healthy social development (e.g. forming positive relationships).

Socialization has three functions:

• It regulates behaviour (e.g. morality).
• It promotes personal growth (e.g. motivation to work hard)
• It promotes social order (e.g. socialized adults communicate what they have learned to their own children).

Vygotsky states that the sociocultural context influences development. He emphasizes the importance of social interaction (i.e. all development goes through social interaction) and he states that the elementary mental functions (e.g. memory; sensation) become higher mental functions as a result of social interaction. This would mean that all cognitive skills have social origin.

The zone of proximal development focuses on the role of joint involvement episodes where the caregivers make use of scaffolding techniques. The social learning theory (i.e. Bandura) states that learning occurs through observation (i.e. social models). There are several factors influencing observation:

• Attention (i.e. factors influencing the amount of attention paid to the model)
• Retention (i.e. factors influencing the cognitive organization of observation in memory).
• Reproduction (i.e. factors influencing the ability to reproduce behaviour).
• Motivation (i.e. factors influencing the motivation to reproduce behaviour).

Bandura demonstrated that there is a strong person-environment interaction. This means that a child’s predisposition is strongly influenced by the environment. For example, a more aggressive child will become the most aggressive when that child is exposed to aggression but not when this child is exposed to positive models.

The social information processing theory states that there are different steps in social interaction:

1. Encoding
   This refers to the encoding of social cues and goals in memory.
2. Interpretation
   This refers to the attribution of intent.
3. Response search
   This refers to searching for a response (i.e. unconscious, fast process).
4. Response decision
   This refers to evaluating the response based on goals, expected results and self-efficacy.
5. Enactment
   This refers to enacting the response.

Each stage of the theory can be a target for an intervention (e.g. treating interpretation bias). All stages are also influenced by one’s mental state. Joint attention (1), emotion regulation (2), inhibitory control (3), imitation (4), causal understanding (5) and language (6) are emotional, cognitive and behavioural skills involved in harmonious peer interactions. In preschool, there is consolidation of these social skills and they are applied in the context of a group. The capacity for prosocial behaviour increases in childhood.

Empathy refers to being able to understand other’s feelings and one’s own feeling in the same situation. It is age-related as it improves with development and is mostly a learned skill through modelling (1), affectively oriented discipline (2) and sensitive parenting (3). Empathy is demonstrated in reacting to other’s distress and empathetic behaviour is already shown at a very young age. It is the root of prosocial behaviour (e.g. altruism). However, there is no consensus regarding the definition of empathy. The definitions of empathy vary in their reference to the sharing of another’s emotional state (1), the explicit understanding of another’s emotional state (2) and the prosocial behaviour that is the result of empathy (3).

Empathetic responses are automatic and there are different empathetic responses:

• Affective responses
  This refers to an affective response that is more appropriate to someone else’s situation than to one’s own situation.
• Cognitive response
  This refers to intellectually taking the role or perspective of another person, decoding and labelling emotions.

The cognitive aspect of empathy is the same as theory of mind (i.e. perspective-taking). According to Hoffman, there are different stages in the development of empathy.

Parenting behaviour which includes the provision of clear rules and principles (1), empathetic caregiving (2), attributing prosocial qualities to the child (3) and modelling by the parent (4) are more likely to lead to prosocial behaviour in the child. There are several predictors of prosocial behaviour:

• Altruism.
• Empathy.
• Moral development.
• Genetic factors.
• Parenting behaviour
• Cultural context

There are two types of relationships:

1. Vertical relationship (e.g. student and teacher)
   This is a hierarchical power difference and it is asymmetric. The main function is security, protection and guidance.
2. Horizontal relationship (e.g. peers)
   This is a relationship with the same power level and the relationship is symmetrical. The main function is cognitive, emotional and social skills learning.

While peer relationships in early life are horizontal relationships, in adolescence they also fulfil the function of vertical relationships. Mixed-age peer interaction refers to interactions among children who differ in age by a year or more. The asymmetry in this interaction could help children acquire certain social competencies. The presence of younger peers may foster the development of compassion (1), caregiving (2), prosocial inclinations (3), assertiveness (4) and leadership skills (5). This does not have the same influence as sibling contact as sibling status is determined by birth order and peer status is more flexible.

There are several developmental trends for peer interactions:

1. Infancy
   There is interest in other infants at three months of age but interactive behaviour does not occur until 1.5 years. There are many unreciprocated approaches.
2. Toddlerhood
   There are more frequent and complex interactions. There is the start of reciprocal play and the start of turn-taking.
3. Preschool years
   There is more symbolic play and verbal skills for communication develop. There is an increasing capacity for group play.
4. Childhood
   There is a substantial increase in the capacity to read other’s minds and children become selective in choosing their play partners (e.g. seeking out same-minded; same-sex partners). Peer groups begin to form important parts of life.
5. Adolescence
   There is increasing interest in other-sex relationships and the peer group becomes a reference group for a sense of identity. The definition of peers changes from shared outside activities to shared mindsets and attitudes.

Contingent peer interactions (i.e. contingent responsiveness) refers to an interaction that resembles turn-taking and can be observed at six months of age. Infants are better at this when a toy is not present. Most conflict between peers in young children regards the possession of toys or violation of personal space and the conflicts are characterized by communicative gestures and signs of social influence. In toddlerhood, preferences for playmates and same-sex peers develop. Stable individual differences in aggression and externalizing problems emerge during toddlerhood.

An infant’s ability to engage successfully in interaction with peers requires several skills:

• Joint attention (e.g. pointing)
• Emotion regulation
• Inhibitory control
• Imitation (i.e. harmonize with the peer)
• Causal understanding (i.e. understanding of peer as active and intentional agent)
• Language

Deficits in either of these skills could hinder adjustment to peers in group settings and impair peer relationships. Causal understanding is associated with intentional communication (1), referencing (2), aggression (3) and prosocial behaviour (4).

There are different types of interaction in early childhood:

• Conversation
  This refers to talking to a peer and competence is greatest when one can rely on script knowledge.
• Cooperation
  This refers to cooperating activities and the degree of cooperativeness or competitiveness is affected by gender (1), culture (2), attachment status (3) and whether the peer is a friend (4).
• Helpfulness, sympathy and kindness (i.e. prosocial behaviour)
  The capacities for this increase over childhood and gender differences in prosocial behaviour depend on the social context.
• Conflict and aggression
  The overall frequency of conflict remains stable throughout childhood though the focus changes (i.e. on resources or social issues).

There are four types of play:

1. Non-social play
   This refers to solitary play without paying attention to others.
2. Parallel play
   This refers to solitary play next to somebody with occasional attention to the other child.
3. Associative play
   This refers to children playing the same game and they ask each other questions but they are not working together.
4. Cooperative play
   The refers to play where children work together with one another, following rules and guidelines.

Passive, constructive solitary play (e.g. build tower of blocks) is positively associated with emotional adjustment and social competencies among kindergarten girls but not boys. Children whose play was more complex are more outgoing (1), pro-socially inclined (2), less aggressive (3) and less withdrawn (4). The cognitive complexity of a child’s play is an important predictor of future social competencies with peers.

Pretend play refers to imaginative pretence where one actively experiments with social roles. There is a shared responsibility and the play revolves around solving a problem. Pretend play may be important in the development of communication skills (1), emotional understanding (2), social perspective-taking (3) and enhanced capacity for caring (4). The complexity of pretend play increases with level of language and pretend play fosters friendships. Pretend play may have three developmental functions:

• It may help children master ways of sharing meaning with peers.
• It provides opportunities for young children to learn to compromise (e.g. negotiation for roles)
• It permits children to display feelings that may bother them, allowing for emotional development

A peer group refers to a group that provides one with a sense of membership and formulates norms. In this group, children often discover the value of teamwork (1), develop a sense of loyalty (2) and develop commitment to shared goals (3). A clique refers to a small group of friends. A crowd refers to a larger, reputationally based peer group. It consists of cliques that share similar norms, interests and values. Identifying with a crowd can be harmful if the norms and values are harmful (e.g. positive of substance use). Cliques and crowds allow adolescents to try out new roles and express emerging values as they begin to forge an identity apart from their family. Group activity in children is characterized by friendships (1), gender segregation (2), dominance hierarchies (3) and peer acceptance and rejection (4).

Peer acceptance refers to which degree children are accepted by their peers and this is influenced by the social environment (e.g. the mother’s social network) and the child’s style of interaction. Children who are indirectly monitored by their parents during play (as compared to directly monitored) are liked better by peers. Peer acceptance is influenced by prosocial behaviour (1), aggressiveness (2), shyness (3), parenting style (4), temperamental characteristics (5) and cognitive skills (6).

Prosocial behaviour tends to be stable throughout childhood and is a key factor in gaining acceptance. The influence of aggression on peer rejection depends on the beliefs about the stability of aggressive behaviours in peers (e.g. entity beliefs). Sociometry refers to a method for the classification of peer acceptance. It asks children who they like and who they dislike and it is not the same as peer assessment.

There is a bi-directional relationship between peer relationships and children’s disorders. Variation in responsiveness to young peers may relate to general individual differences in emotionality and behavioural inhibition. There are three processes that are important for peer acceptance in the preschool years;

1. Emotionality and emotion regulation
   The experience of negative emotions and problems in regulating those have long-term consequences for peer relations. Negative emotionality and problems with emotion regulation interfere with social competence. This is associated with aggression (1), lack of prosocial skills (2) and shyness (3).
2. Social understanding
   This predicts competence in peer interactions. Problems in social understanding can be biases or deficits (e.g. deficit in theory of mind) and are associated with aggression and lack of prosocial skills.
3. Executive function
   This is associated with a lack of prosocial skills and aggressiveness.

There are several types of children:

1. Popular children
   They have more happy dispositions (1), are more physically attractive (2), have high levels of cooperation (3), have a willingness to share (4), have good leadership qualities (5) and have little aggression (6).
2. Neglected children
   These children are more shy and unassertive (1), show little antisocial behaviour (2), are rarely aggressive (3), withdraw in the face of others’ aggression (4), show a lot of solitary play (5) and avoid dyadic interaction (6).
3. Rejected children
   They show more disruptive and inappropriate behaviour (1), are often antisocial (2), are extremely active (3), have frequent attempts at social approaches (3), show much solitary play (4), have little cooperative play (5) and are unwilling to share (6).
4. Controversial children
   These children are liked by many but also disliked by many. They often display mixed behavioural profiles.
5. Average children
   These children are liked by some and disliked by some.

The average and popular status are stable in the short-term but not in the long-term. Rejection status tends to be more stable over time. This may be due to biases as the negative behaviour is attributed to stable causes and prosocial behaviour is attributed to dispositional causes. The opposite pattern occurs for liked children. Neglected children are not less socially skilled than average children.

There are two types of rejected children:

1. Aggressive rejected children
   They show more externalizing behaviour (e.g. hostility; lack of control; distractibility). These children have experience with more punitive, hostile and abusive family treatment. They tend to interpret others’ behaviour as hostile and favour retaliation and they rarely show prosocial behaviour.
2. Unaggressive rejected children (i.e. withdrawn-rejected children).
   They show more internalizing behaviour (e.g. fearfulness; anxiety; withdrawal). They display many unusual and immature behaviours and are insensitive to peer group expectations. They are quick to anger in response and prefer retaliation.

Changes in social status have behavioural implications (e.g. aggressive children that are accepted typically become less aggressive over time). Popularity and likability are not the same and likability is more adaptive for adolescents.

Children who are aggressive but were not victimized experienced more adult aggression and conflict but were not necessarily victimized by adults. It is possible that children who are more aggressive are more often rejected by peers and this leads them to develop a friendship with more aggressive peers. This increases the risk of conduct disorder. However, peer rejection and early aggression could also independently increase the risk of conduct disorder.

The base rate of aggression within a peer group influences whether aggressive children are rejected (i.e. aggressive behaviour is evaluated in light of the social norms of the peer group). There is more conflict in aggressive peer groups and this may lead to more aggressive episodes (i.e. friendships facilitating aggression). One important method of decreasing aggression may be reducing the time spent with the deviant peer group. Association with deviant peers around 14 or 15 years of age has the biggest impact on criminal activity and substance use.

Peer rejection is predictive of antisocial behaviour and may be especially detrimental to children who already show maladaptive behaviour. Girls and reactive-aggressive children are most vulnerable to the consequences of peer rejection.

Neglected children also show more internalizing behaviour. When it comes to children’s status and their characteristics, there is an issue of causality. It is unclear whether children with more social characteristics become more popular or whether children who are excluded develop less competence. A bidirectional relationship is likely and this may be responsible for high stability in peer acceptance over time. The rejected children have the most stable peer status.

Friendship can be differentiated from popularity as not all popular children have good friends and not all low-accepted children are without a best friend. Friendships become more stable with age. There are several functions of friendship:

• Source of companionship and fun.
• Context of skill acquisition.
• Source of self-knowledge and knowledge about others
• Emotional support in face of stress.
• Forerunner of subsequent relationships (e.g. romantic).

Lonely children have more emotional problems (1), lag behind others in perspective-taking skills (2), are less altruistic (3), are less sociable (4), make fewer educational gains (5) and have lower levels of peer competence (6). Chronic loneliness predicts low social skills (1), depression (2), aggression (3) and suicidal ideation by age 15 (4). Lonely children are rejected and victimized by their peers more often leading to them getting rejected more often over time. However, the effect of being alone depends on the developmental stage (e.g. negative in middle childhood; positive in adolescence).

Anxious solitude refers to being alone due to anxiety and while it is not the same as solitude due to peer exclusion, it predicts peer exclusion. There may be intergenerational transmission of loneliness as loneliness is related to how parents socialize their children and resolve difficulties that arise during interactions with their peers. A controlling interaction style is associated with loneliness.

There is individual variation in the susceptibility to feeling lonely. People seek social connection for a sense of safety, meaning that adverse peer experiences early in life (e.g. victimization) lead to more loneliness, partially depending on one’s susceptibility to feel lonely.

Bullying has several characteristics:

• It takes place between peers of similar age.
• It takes place in an online or offline environment.
• It is characterized by an imbalance of power in the favour of the perpetrator.

There appears to be a decrease in bullying over time. This may be due to a decrease in self-report or due to the increase of assertiveness and social skills. Boys are victimized more often and the bully is often a same-sex peer. Early family experiences predict what role children take in bully-victim relationships (e.g. bully). Bullies do not necessarily have a poor theory of mind or social skills as they may need this to bully someone.

Bullying victimization is associated with loneliness over and above concurrent psychopathology, social isolation and genetic risk. Childhood bullying predicts loneliness in young adulthood even in the absence of ongoing victimization. Emotional maltreatment may disrupt the formation of secure attachments and this negatively shapes individuals’ perceptions of their relationships with others. Polyvictimization refers to the experience of multiple victimizations of different types and is a strong predictor of negative outcomes.

People who have been victimized in both childhood and adolescence were lonelier than people who were victimized in one of these time periods. Being bullied while seeing other peers have normal relationships could elicit a sense of injustice and perception of oneself as an outsider. This feeling could increase feelings of isolation and loneliness. Bullying may also increase loneliness through diminished self-esteem (1), social anxiety (2) and elevated sensitivity to social rejection (3). The effect of victimization on loneliness may vary according to the developmental stage in which it is experienced.