“It is widely acknowledged that age plays a role in the development of judgment and moral sophistication” (D.B. at para 62). Chronological age is therefore an important personal attribute, but it is only one factor in assessing developmental maturity (I.M. at para 152). There is potential for error where the judge infers, based solely on a youth’s proximity to adulthood, that their developmental maturity is adult-like. Doing so would improperly reverse the presumption of diminished moral blameworthiness and violate the young person’s constitutional rights under s. 7 of the Charter.

A young person’s social context, including their community, lived experiences, and exposure to trauma, can profoundly shape their life trajectory. Understanding that context helps situate their decisions and may reveal increased vulnerability, diminished judgment, or reduced moral capacity for decision-making (I.M. at para 166). Social context evidence is therefore relevant to the factual inquiry into the young person’s developmental age and may indeed be “critical” (I.M. at para 179 and S.B. at para 50). This aligns with s. 3(1)(c)(iv) of the YCJA, which explicitly states that measures taken against young persons should respect “ethnic, cultural and linguistic differences and respond to the needs of aboriginal young persons […]”.

In S.B., the Court considered the young offender’s difficult upbringing: the loss of a cousin to gun violence, the realities of growing up as a Black youth in a crime-ridden neighbourhood, and his experiences with and perceptions of the police in his community (para 54). This social context evidence was found in an enhanced pre-sentence report (EPSR), also known as Impact of Race and Culture Assessment (IRCA). See the NJI’s Sentencing Black Offenders Self-Study Course for more information on these reports.

Evidence of cognitive or emotional limitations – including behavioural disorders and mental health concerns – can indicate heightened vulnerability, reduced maturity, and a diminished ability to exercise independent judgment or make rational, informed decisions at the time of the offence. A young person with cognitive impairments may have difficulty anticipating the consequences of their actions or fully understanding the harm caused, highlighting their diminished capacity for moral decision-making (I.M. at para 155).

In I.M., the young offender displayed impulsivity and poor emotional regulation, both of which pointed to an underdeveloped level of adult moral judgment. His peer delinquency, lapses in supervision, and low academic performance further reflected social susceptibility, environmental instability, and limited cognitive development (I.M. at para 207).

For some young persons, gang affiliation can act as a “refuge-seeking response to social dislocation or a lack of family stability, physical protection, or emotional or financial support” (I.M. at para 166).  

In S.B., the young offender’s early exposure to older gang members, followed by deeper gang involvement, provided context for assessing his life circumstances and for situating his behaviour within his level of maturity and capacity for independent judgment (para 53). 

Impulsiveness or bravado may signal lower maturity, whereas deliberate planning may indicate more advanced moral and cognitive development, including greater critical thinking and understanding of the consequences of their actions (I.M. at para 147).

In S.B., the young offender played a “clear leadership role” in the commission of the offence. His conduct was deliberate and measured, demonstrating self-control and independence. He issued careful and detailed instructions to his co-accused, also youths of similar age, in planning the murder using two cellphones (paras 54 and 56).

The young person’s post-offence conduct can shed light on their maturity, moral sophistication, and capacity for independent judgement, but must be approached with caution. Behaviours such as evading police, destroying evidence, or mitigating the harm may, in some cases, reflect planning and moral judgment. In other cases, the same actions may simply be impulsive reactions rooted in fear or panic rather than adult‑like reasoning. Post‑offence conduct must therefore be assessed in its full context to avoid overinterpretation (I.M. at paras 148–149).

In I.M., in the days following the offence, the young offender recounted his crime to a schoolmate and exhibited the victim’s bloodied clothes. This behaviour was considered “imprudent in the extreme”, showing “bravado consonant with the impulsivity of an adolescent and stood in contrast to the capacity for moral judgment that one would expect from an adult” (para 202).

In S.B., the young offender’s post-offence conduct showed that he maintained a firm leadership role in the cover‑up of the offence: he assisted his co‑accused in concealing the murder and went so far as to express an intention to kill a co‑accused and that co‑accused’s mother and sister (para 57).

Conduct influenced by adults or older criminal actors may reflect the young person’s immature susceptibility, including a reduced capacity to measure consequences carefully, consistent with adolescent risk-taking and limited independent judgment.

In I.M., the young offender sent a text to an adult co-conspirator suggesting he viewed the crime as a stepping stone to future criminal activity (para 201). This demonstrated that he was susceptible to social pressure from adults and failed to measure consequences as someone with adult maturity. 

In S.B., the Court noted a lack of influence of adults or older peers (para 56).

Depending on the case, conduct in pre-trial detention can shed light on the young offender’s developmental stage at the time of the offence. A genuine evolution of the young person’s behaviour over time, such as signs of growth, progress, or a shift consistent with moving towards adulthood, may suggest a lesser degree of maturity at the time of the offence. Conversely, consistently immature behaviour may indicate stalled development on the part of the young person (I.M. at para 158).

In S.B., the young offender continued to engage in antisocial conduct during pre‑trial custody. He was described as effectively “running the unit” and acting as a “skilled behind‑the‑scenes manipulator.” This indicated that there had been no positive change since the offence and suggested that his participation in the murder did not stem from immaturity or limited insight (paras 49 and 57).