Adolescent development is not only shaped by the mere passing of time and accumulating
experience, but it also depends on pubertal timing and the cascade of maturational
processes orchestrated by gonadal hormones. Although individual variability in puberty
onset confounds adolescent studies, it has not been efficiently controlled for. Here
we introduce ultrasonic bone age assessment to estimate biological maturity and disentangle
the independent effects of chronological and biological age on adolescent cognitive
abilities. Comparing cognitive performance of female participants with different skeletal
maturity we uncover the impact of biological age on both IQ and specific abilities.
We find that biological age has a selective effect on abilities: more mature individuals
within the same age group have higher working memory capacity and processing speed,
while those with higher chronological age have better verbal abilities, independently
of their maturity. Based on our findings, bone age is a promising biomarker of adolescent
maturity.
