Puberty refers to a set of biological changes involved in reaching physical and sexual maturity. This is universal. Adolescence refers to the life course between beginning puberty and adult status. It roughly contains the ages 10-18. In this stage, young people are preparing to take on the roles and responsibilities of adulthood in their culture. It is culturally constructed as the length (1), content (2) and daily experiences (3) differ across cultures. It is typically characterized by:

• Conflicts with parents.
• Mood disruptions.
• Risk behaviour.

It is debated whether this is a period of ‘storm and stress’ as this may depend on culture and individual characteristics. It may be context dependent how one experiences this period although it is more likely during this period that people experience storm and stress. Recapitulation states that the development of each individual re-enacts the evolutionary development of the human species as a whole. Adolescence was seen as reflecting a time of evolutionary turmoil and this was used as an explanation why adolescence is characterized by storm and stress.

Emerging adulthood refers to the life course between beginning puberty and having adult status. This roughly contains the ages 18-25. It is characterized by:

• Identity exploration.
• Instability
• Focus on the self.
• Feeling in-between.
• Possibilities.

These characteristics are not unique to emerging adults as it occurs in childhood already and become more abstract during adolescence. However, it becomes more future-oriented (e.g. focus on future job; future partner) during emerging adulthood. People in this stage explore various possibilities in love and work and move towards making enduring choices. Emerging adults focus on themselves to develop knowledge, skills and self-understanding needed for adult life. Emerging adulthood is culturally dependent. Youth refers to both adolescence and emerging adulthood.

The family (1), peer (2), school (3) and social media context (4) are important during adolescence and emerging adulthood. The authoritative parenting style is ideal for adolescence as it is very democratic. This is because adolescents are good at regulating themselves and have a desire for increasing autonomy. This parent style balances allowing autonomy to develop capacities and requiring the child to use this autonomy appropriately.

The family context is a complex system which consists of complex interactions characterized by reciprocal effects between parents and children. It is a transactional model. The parent-adolescence conflict increases during adolescence, especially from the age of 11-12 to 15-16. This is because:

• There is an increased capability of abstract thinking in adolescence. This makes it more difficult for parents to find good arguments.
• There is a new degree of autonomy and there is conflict regarding boundaries (e.g. curfew).
• There are topics which are difficult to talk about (e.g. sexuality) and this makes communication unclear.

However, during adolescence, there is also a lot of agreement on topics (1), love (2) and respect (3).

In adolescence, the self-conceptions are different from childhood because of cognitive development. It becomes more trait-like and less concrete (e.g. “I am outgoing”). This is because of more abstract and complex thinking. Identity refers to one’s perception of their capacity and characteristics and how this fit into the opportunities available to them. The self-conception depends on individualistic or collectivistic cultures as it is defined by social relationships in a collectivistic culture. The cognitive capacity of self-reflection (e.g. “who am I?”) makes identity possible. There are many explorations (e.g. trying a new hobby) and this eventually leads to commitment.

The ideal self refers to the person the adolescent would like to be. The feared self refers to the person the adolescent imagines it is possible to become but dreads becoming. The false self refers to a self that adolescents present to others while realizing that it does not represent what they are actually thinking and feeling. A discrepancy between the actual and ideal self can lead to problems but can work as a motivator.

Adolescents are able to engage in frequent self-reflection because they are often by themselves. Their moods tend to be lower when they are alone but their moods tend to rise after a period of being alone. The time alone may be used for self-reflection and mood management. It can thus be constructive as long as the adolescent is not alone too often.

Social loneliness refers to the perception of lacking a sufficient number of social contacts and relationships. Emotional loneliness refers to the perception of lacking closeness and intimacy in social relationships. Both types of loneliness are more common in adolescence and emerging adulthood and especially emerging adulthood may be lonely due to the increases in independence without companionship (e.g. a partner).

Erikson’s theory states that every life phase is characterized by a crisis (i.e. healthy development or unhealthy development). According to this theory, the main crisis in adolescence is identity vs. identity confusion. The key areas where identity are formed are love, work and ideology. Identity is relevant throughout development but is most prominent in adolescence.

Identification refers to relationships formed with others in which love for another person leads one to want to be like that person. Identity is formed after identifications (e.g. adolescents model themselves after others). The most important identifications are combined and integrated with individual characteristics.

Erikson’s identity status model consists of four identity statuses:

1. Achievement (i.e. exploration and commitment).
2. Foreclosure (i.e. no exploration but commitment).
3. Moratorium (i.e. exploration but no commitment).
4. Diffusion (i.e. no exploration and commitment).

Moratorium is often seen in adolescence and identity formation rarely concludes in adolescence. However, Erikson’s theory is narrow and outdated because of three reasons:

• It does not take different cultural contexts into account.
• It holds that identity is stable after commitment but this is not the case.
• It holds that striving for an independent identity is essential and desired while girls often put emphasis on relationships with others.
• There are no predictable stages culminating in identity achievement.

According to postmodernists, identity consists of diverse elements (1), is not consistent and not unified (2), is context-dependent (3) and develops and changes throughout life (4).

Ethnic identity is more salient when one is part of a minority. Adolescents who are part of an ethnic minority may become more aware of prejudices and stereotypes and having to confront these issues may make identity development more complex. Emerging adulthood may be especially important for developing ethnic identity because emerging adults often enter new contexts that may involve greater contact with people outside their ethnic group.

Self-esteem is also different from childhood. There is a stronger focus on physical appearance and this holds more for girls than for boys. In puberty, there often is weight-gain (e.g. breast development). Girls tend to evaluate oneself more negatively, partially due to the increases in weight-gain and this leads to girls typically having a lower self-esteem than that of boys.

Emotions are also different from childhood. There is an increased understanding and managing of heightened emotions. However, there are also more extreme emotions (e.g. extreme sadness) and more fluctuations. Next, in adolescence, there typically also is a decline of positive emotions. This is associated with environmental factors and biological changes. One task in adolescence is to deal with these emotions and manage it.

It is important to evaluate whether there is a trait or a state of personality. A trait holds across contexts and a state depends on the context. There are discussions about stability and change of personality characteristics. Reciprocal links between personality traits and social relationships exist which may indicate co-development of personality with social relationships.

Rank-order stability refers to the degree to which the relative ordering of individuals on a given trait is maintained over time. This is indexed by test-retest corelations. Mean-level change refers to absolute change in the individual’s level of a certain trait over time and this can be demonstrated using longitudinal studies.

The cumulative continuity principle of personality development refers to personality and temperament being moderately stable in preschool years and becoming increasingly stable until middle adulthood. The maturity principle of personality development refers to young adults increasing on absolute levels of agreeableness (1), emotional stability (2), conscientiousness (3) and social dominance (4). The disruption hypothesis states that adolescents tend to experience temporal dips in personality maturity as a result of biological, social and psychological transitions from childhood to adolescence.

Adolescents may not fit the maturity principle because they temporarily conform to deviant peer norms and experience difficulties in adjusting to increasingly mature expectations. There is an U-shaped change in the mean levels of most Big Five traits. Co-development refers to the tendency of group members to show interrelated development on a trait because of their social connectedness. There are several possible trajectories:

1. Convergence
   This refers to dyad members becoming more similar over time.
2. Correlated change
   This refers to change trajectories being correlated.
3. Time-lagged partner effects
   This refers to one person’s change being associated with the other’s previous trait level.

Co-development may result from social learning processes (1), conformity to social norms for behaviour and other personality expressions (2) or shared environmental experiences (3). People’s rank position tends to remain stable while there are mean-level changes. Rank-order becomes increasingly stable in early and middle adolescence but this does not increase further in late adolescence.

There is increasing agreeableness in boys and girls throughout adolescence and early adulthood. There is increasing conscientiousness for girls. There is a temporal decline in boys’ conscientiousness and girls’ emotional stability. The mean-level increases in conscientiousness may be driven by increases in self-regulation capacity and expectations regarding behaviour. The temporal dip may be explained by a temporary mismatch between external expectations and actual behaviour, affect and cognition.

The Big Five of personality is a data-driven taxonomy which holds that personality is static while it only accounts for 56% of normal personality traits. There may be a sixth trait or other traits which only express themselves in different cultures. It is not a theory.