Social sensitivity refers to the heightened attention, salience and emotion relegated to processing information concerning social evaluations and social standing in adolescence. Social sensitivity could intensify socioemotional processes (e.g. more attuned to instances of perceived social evaluation).

There are three types of patterns of brain development:

1. Age-linear patterns
   This refers to patterns which increase or decrease with age at a consistent pace.
2. Adolescent-specific patterns
   This refers to patterns which are specific to adolescence (e.g. strong increase in adolescence but stable in childhood or adulthood).
3. Adolescent-emergent patterns
   This refers to a rapid rate of change and a possible peak during adolescence that persists or partially resolves into adulthood.

Adolescent-emergent patterns imply developmentally mediated shifts that are constrained by maturational processes that solidify in early adulthood.

The socioaffective circuitry is critical for detection of salient information (1), assignment of hedonic, aversive or emotional value to that information (2), social cognition (3) and the use of that information to guide learning and behaviour (4). It includes the amygdala (1), striatum (2) and the medial prefrontal cortex (3).

The socioaffective circuitry may be especially important in adolescence as it develops. This may be because the prefrontal cortex continues to reach structural and functional maturity throughout adolescence. Next, the connections between subcortical and cortical structures continue to strengthen. The influx of hormones during puberty may sensitize functional properties of certain brain circuits and the still-maturing connections between subcortical and cortical brain regions may reduce the capacity to exert cognitive or emotional regulation, especially in emotionally salient contexts. This may lead to adolescent-specific engagement patterns. Sensitized socioaffective circuits which are not optimally regulated (i.e. due to an immature prefrontal cortex) could sharpen the detection of and response to salient cues during adolescence.

There are three general tasks to study the effect of social feedback:

• Photograph task
  In this task, adolescents saw the rating that ‘others’ (i.e. the researchers) gave to their own pictures.
• Chatroom tasks
  In this task, adolescents see whether a peer (i.e. the researcher) chose them or somebody else to chat about mutual interests.
• Cyberball task
  In this task, adolescents are tossing a virtual ball with two others and may or may not be excluded.

Adolescents show heightened positive and negative emotional responses in these paradigms. There is a greater drop in mood and a greater increase in anxiety after receiving negative social feedback in adolescents compared to adults. All adolescents show a heightened pupil response to rejection social feedback and this is more so in older adolescents. This predicts less connectedness. However, adolescents also experience a boost in positive affect when experiencing social acceptance from a desirable peer.

Adolescents engaged similar regions of the brain as children and adults when processing social feedback. However, adolescents’ activity increased with age within the striatum and subgenual anterior cingulate cortex (i.e. regions that support emotional valuation) while anticipating positive feedback. Adolescents recruited the medial prefrontal cortex more strongly than adults and make use of regulatory regions of the lateral prefrontal cortex less strongly while being excluded. Thus, adolescents engage socioaffective processes and reduce recruitment of regulatory circuitry while processing emotional qualities of social feedback.

Adolescents are hyperaware of others’ evaluations and feel they are under constant scrutiny by an imaginary audience. Adolescents report a greater day-to-day tendency to feel self-conscious and adolescents respond with a greater release of cortisol when under social scrutiny. Social evaluative situations, regardless of feedback, induce self-consciousness and engage stress systems of the body in adolescents.

Adolescents experience more embarrassment and have a heightened responding of the autonomic nervous system if they think that they are being watched. Adolescents’ social sensitivity includes subtle evaluative contexts. Adolescents engage the medial prefrontal cortex and this mainly emerges in adolescence. This may reflect or result in social evaluative situations being assigned a high degree of salience, emotional arousal and self-relevance.

Theory of mind matures throughout adolescence as adolescents perform worse than adults when theory of mind tasks are highly complex. The social brain refers to a subset of the socioaffective circuitry which supports theory of mind processes. It includes the medial prefrontal cortex (1), temporoparietal junction (2) and the superior temporal sulcus (3).

Adolescents have a more robust medial prefrontal cortex recruitment compared to adults in tasks that require to consider the thoughts and intentions of others. There is also a heightened task-based functional connectivity between brain regions important for social cognition in adolescents compared with adults.