 13. Personality in Adolescence  309
though they gradually increase toward age 
50. Developmental patterns for altruism and 
compliance seem to follow this pattern, with 
more outspoken sex differences for altruism 
(with females consistently higher), already 
present during puberty. Neuroticism showed 
opposite developmental patterns for boys 
and girls before age 20, with a steeply in -
creasing pattern for neuroticism in girls and 
a decreasing pattern for boys, showing the 
largest difference between genders between 
ages 16 and 25. Neuroticism scores of fe -
males start to decrease after age 16 and fur -
ther decrease at a faster rate after their 30s. 
Males age 20 show the lowest neuroticism 
scores, followed by a slow increasing to sta -
ble levels, with an additional decrease after 
age 50. Anxiety followed the general pattern 
described for neuroticism, but depression in 
boys, although lower than for girls, showed 
an increase midpuberty, followed by an ad -
ditional increasing pattern between ages 20 
and 30, leveling off after age 55. For extra -
version, there is a decrease from ages 10 to 
15, with an outspoken sex difference at age 
15, with boys lower than girls. This pattern 
remains largely unchanged until 50 years of 
age, followed by a diminishing of sex differ -
ences. The pattern for assertiveness follows 
the general pattern for extraversion, where -
as activity level shows a sharper decreasing 
trend in puberty, with sex differences dimin -
ishing after age 25. Finally, openness shows 
a decreasing trend for females from ages 10 
to 20, whereas the decrease for boys seems to 
occur earlier in adolescence, with a faster in -
crease into young adulthood. Sex differences 
are reversed in puberty, with boys initially 
scoring slightly lower than girls, and show -
ing an outspoken sex difference at age 25, 
lasting until age 55, with males obtaining 
higher levels. Females showed higher scores 
on aesthetics across all age groups, with the 
largest differences between ages 10 and 20, 
but also after age 50. For openness to ideas, 
large sex differences were manifested from 
midpuberty onwards, with males higher 
than females.
De Bolle and colleagues (2015) used a dif -
ferent data source: Rather than self-  reports 
by adolescents, they examined ratings of 
adolescents by informants (e.g., a 16-year-
old adolescent described by an adult) from 
23 different cultures ( N = 4,850) from around the globe. Despite the different data 
source and sample, they largely confirmed 
Soto et al.’s (2011) findings, with some no -
table exceptions for conscientiousness. Girls 
between ages 12 and 17 scored consistently 
higher in conscientiousness than did boys in 
De Bolle et al.’s (2015) study. This finding, in 
association with their higher scores on open -
ness, has been suggested as an explanation 
for girls’ higher achievement, especially in 
secondary education (De Fruyt, Van Leeu -
wen, De Bolle, & De Clercq, 2008; Voyer & 
Voyer, 2014). De Bolle et al.’s work (2015) 
showed that by the end of adolescence, indi -
viduals in various cultures increasingly con -
verge toward adult sex difference patterns in 
terms of both direction and magnitude.
These developmental patterns describe 
the normative personality trajectories that 
people on average tend to follow, with vari -
ous possibilities for unique developmental 
trajectories (for a more detailed empirical 
account, see, e.g., Schwaba & Bleidorn, 
2018). Overall, these normative trends ob -
served in adolescence suggest that, after the 
dip in midadolescence, personality develop -
ment moves in the direction of greater matu -
rity. The rate of change, however, seems to 
be especially pronounced in childhood and 
adolescence, although there are cultural dif -
ferences in the rate of personality develop -
ment for some personality traits. It has been 
suggested and demonstrated that social in -
vestments, such as moving earlier into adult 
work roles, may serve as an accelerator of 
these changes (Bleidorn et al., 2013). Yet 
several other studies have shown that other 
apparent accelerator factors, such as becom -
ing a parent, do not necessarily affect per -
sonality in the direction of greater maturity 
(Bleidorn et al., 2016; Bleidorn & Denissen, 
Chapter 14, this volume; Van Scheppingen, 
Denissen, Chung, Tambs, & Bleidorn, 2018; 
Van Scheppingen et al., 2016). Thus, future 
studies need to investigate further the mech -
anisms behind these rate fluctuations.
Personality and  Consequential  Outcomes
The considerable interest in personality as -
sessment and development in adolescence 
has also been driven by research on the va -
lidity of traits to shape and explain conse -