Juvenile Justice and Developmental Issues
This domain tests developmental science applied to culpability, competence and sentencing, where adolescent immaturity alters both legal standards and assessment strategy.
Culpability and sentencing
US Eighth Amendment cases: Roper v Simmons (2005) bars the death penalty for offences committed under 18; Graham v Florida (2010) bars life without parole for non-homicide offences; Miller v Alabama (2012) requires individualised consideration of youth before life without parole; Montgomery v Louisiana (2016) made Miller retroactive. Steinberg's dual-systems model describes heightened reward sensitivity alongside still-maturing self-regulation, which bears on culpability rather than factual guilt.
Age and responsibility
In England and Wales the age of criminal responsibility is 10, and doli incapax was abolished by the Crime and Disorder Act 1998 s34. Scotland raised the age to 12 under the Age of Criminal Responsibility (Scotland) Act 2019.
Competence and interrogation
Juvenile competence is assessed developmentally across understanding, appreciation, reasoning and choice, using tools such as the MacArthur Competence Assessment Tool - Criminal Adjudication or juvenile competence measures. Youths waive rights without appreciating long-term consequences and are over-represented in false confessions.
Worked example
A 13-year-old with a reading age of 8 waives rights and confesses after four hours. The court applies a totality-of-circumstances test weighing age, education, prior police contact, interrogation length and whether an appropriate adult was present; developmental immaturity can support suppression.
Traps
Equating callous behaviour with psychopathy; applying adult instruments without juvenile norms; assuming word-level understanding equals appreciation of consequences; and ignoring peer influence when assessing culpability.