Rank-order stability refers to the maintenance of the relative standing of individuals on a trait dimension within a population over time. Mean-level change refers to change in the average trait levels of a population over time. Individual difference in change refers to individual deviations from population mean-level patterns of change.

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 the fact that, on average, young adults increase in their absolute levels of agreeableness (1), emotional stability (2), conscientiousness (3) and social dominance (4). These aspects are related to being mature and thus maturing is associated with increases in these factors.

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 also not fit the maturity principle because they temporarily conform to deviant peer norms and experience difficulties in adjusting to increasingly mature expectations.

There seems to be an U-shaped change in the mean levels of most Big Five traits. There may be temporary mean-level decreases in conscientiousness (1), openness (2), extraversion (3) and emotional stability (4) in early adolescence and increases in late adolescence with the emotional stability aspect specifically holding true for girls.

Peers may play an important role in explaining individual differences in adolescents’ personality trait change (i.e. transactional model). 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 of co-development:

1. Convergence
   This occurs when dyad members become more similar over time.
2. Correlated change
   This occurs when the change trajectories of dyad members are correlated.
3. Time-lagged partner effects
   This occurs when one dyad member’s change is associated with the other’s previous trait level.

Personality trait change and personality trait 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).

Adolescents tend to become more stable in their ranking on personality trait dimensions and tend to achieve greater psychological maturity, either linearly or through the U-shape. Adolescents differ regarding their personality trait trajectories but the individual differences in change are not related to personality trajectories of their friends and siblings.

The 1-year rank order stability of Big Five traits increased substantially in early and middle adolescence. Rank-order stability levels do not increase further in late adolescence. This is mostly due to stability of environmental influences. This may be stability of social relationships (1), identity maturation (2) and decreasing brain development of areas associated with personality.

Throughout adolescence and early adulthood, boys and girls showed increasing agreeableness and girls showed increasing conscientiousness. There is a temporal decline in boys’ conscientiousness and girls’

Adolescents show increased attention and neural activation in response to peer acceptance. Feelings of relatedness with others and perceived acceptance during adolescence are associated with higher self-esteem (1), better adjustment in school (2) and greater self-worth (3). Peer rejection in adolescence is associated with school withdrawal (1), aggression (2) and mental health problems (3).

Social contexts are more salient to adolescents. This can lead to different decision-making abilities around peers (e.g. presence of peers increases risky decision making). Adolescents who feel rejected are more likely to engage in risky behaviour to fit in with the group.

Feedback from peers may reinforce behaviour. This may be due to overlapping neural circuitry for evaluating social and non-social rewards. The ventral striatum supports learning from varying amounts of positive social feedback from peers. The most reinforcing peers had a greater influence on social preferences. Choice behaviour (1), neural activity in the ventral striatum (2) and reaction times (3) may be hypersensitive to rewarding stimuli in adolescence. However, it is also possible that the functional connectivity changes and how neural activity guides expectations and behaviours rather than differences in reward-related learning signals.

Participants liked peers that gave them continuous positive social feedback more than those who rarely gave them positive social feedback. Participants liked peers who gave them frequent feedback more than those who rarely gave them positive feedback. There is no difference between the two in preference rating.

Higher learning rates to positive reinforcement reflect vigilance to reinforcement contingencies. This is indicated by a rapid change in behaviour when contingencies were reversed. Adolescents show lower positive learning rates compared to children and adults.

Adolescents showed greater activity in the supplementary motor cortex and in the putamen when receiving positive social reinforcement. Elevated activity within a motor circuit in adolescents when receiving positive social feedback is associated with speeding responses to cues of the least reinforcing peer.

Different amounts of positive social reinforcement enhanced learning in children and adults. However, all positive social reinforcement equally motivated adolescents (i.e. lower positive learning rate). They show elevated activity in response planning circuitry when they receive positive feedback, regardless of the expected outcome. This reiterates that adolescence is a period of unique sensitivity to peers. Adolescents may have an overall vigilance to peer approval. This demonstrates that peers can enhance adolescents’ risk-taking behaviour.

The lower positive learning rates for adolescents could occur if adolescents do not learn to discriminate between the cues that are associated with different amounts of positive social feedback. Alternatively, adolescents’ behaviour may not be captured by simple reinforcement learning.

Adolescents may also have a lower positive learning rate due to increased motivation toward that which is socially the least reinforcing. This may be as adolescents tend to engage in risky behaviour when they perceive themselves as less socially accepted.

There is elevated activity in the insula to social cues in adolescence. The insula

Intervention studies facilitate our understanding about which interventions are most effective in improving educational outcomes.

Theories of motivation regard the energization and direction of behaviour. Social-cognitive theories of motivation include theories focusing on achievement motives and needs (1), perceived ability and self-concept (2), perceived value for and interest in an activity (3), goals (4), attributions about success and failure (5), emotions (6) and potential future identities (7). Motivation refers to processes that are affective, behavioural and/or cognitive and energize and direct behaviour.

Student motivation is essential for learning. Motivated students learn more (1), persist longer (2), produce higher quality work (3) and score higher on tests (4). This is especially the case if they are motivated by relatively intrinsic as compared with extrinsic motivation. Declines in student motivation are a common problem and threaten educational equity. Schools do not seem to be enhancing or maintaining motivation to learn in school at a systematic level.

There are three dimensions of naturalness:

1. Natural treatments
   This refers to naturally occurring events to which the participant is exposed (e.g. curriculum).
2. Natural settings
   This refers to settings that are not established for the purposes of research.
3. Natural behaviour
   This refers to behaviour which occurs without experimental intervention (e.g. centralized exams).

A more natural intervention is more likely to generalize to other settings. There are several theories on motivation:

1. Achievement emotions theory
   This theory leads to interventions that hold that reducing worries about test-taking through expressive writing or enhancing happiness and well-being through personal improvement exercises can improve motivation and achievement.
2. Achievement goal theory
   This theory leads to interventions that encourage students to adopt mastery goals for learning and to value the process of learning as much as the product.
3. Attribution theory
   This theory leads to interventions that help students attribute academic struggles to lack of effort through individual and group activities.
4. Expectancy-value theory
   This theory leads to interventions that help students discover the relevance of academic material to their lives through writing exercises.
5. Goal setting theory
   This theory leads to interventions that help students set specific and realistic academic goals through direct instruction.
6. Implicit theories of intelligence
   This theory leads to interventions that help students realize they can become smarter by tackling challenges.
7. Interest theory
   This theory leads to interventions that excite and engage students in a topic through expressive writing and providing stimulating learning activities.
8. Need for achievement theory
   This theory leads to interventions that encourage students to strive for high achievement through direct instruction in understanding achievement-related emotions and cognitions and adopting higher standards and action strategies.
9. Possible selves theory
   This theory leads to interventions that help students draw connections between successful future selves and current school involvement through interactive activities and written reflections.
10. Self-affirmation theory
    This theory leads