VALUES, EMPATHY, AND FAIRNESS ACROSS SOCIAL BARRIERS
The Development of Adolescent
Stephanie Burnett and Sarah-Jayne Blakemore
University College London, Institute of Cognitive Neuroscience, London, United Kingdom
Adolescence has long been considered a turbulent time; beginning with large changes in
hormonal levels and consequent bodily changes, as well as changes in behavior. Recently,
neuroscience studies have contributed to this picture of turbulence. We now know that
the brain undergoes profound transformation during the teenage years. This paper
focuses on how the social brain—the network of brain regions involved in understanding
other people and self-awareness—develops during adolescence.
Key words: adolescence; social brain; development
Adolescence is deﬁned in humans as the
period of psychological and social transition
between childhood and adulthood. The begin-
ning of adolescence, around the onset of pu-
berty, is characterized by dramatic changes in
hormone levels and, as a result, in physical ap-
pearance. This period of life is also character-
ized by the continued development of social
abilities and behavior as well as neuroanatom-
ical maturation within regions of the brain in-
volved in social cognition.1Recent advances in
cognitive neuroscience are allowing us to begin
to probe the links between unfolding adoles-
cent social cognition and its physical basis in
Milestones in Social Ability
from Birth to Adulthood
Human social preferences are apparent at a
very early age. At only a few weeks after birth,
infants direct more smiles toward their care-
giver and other humans than at inanimate ob-
jects, indicating that they differentiate between
Address for correspondence: Sarah-Jayne Blakemore, UCL Institute
of Cognitive Neuroscience, 17 Queen Square, London WC1N 3AR, UK.
Voice: 0044 20 7679 1131. email@example.com
social and nonsocial beings. From around 1
year, infants deliberately engage and redirect
the attention of their caregiver by pointing or
vocalizing. By about 2.5 years, children im-
plement complex social tactics, such as teas-
ing, lying, and saving face (bravado).2Over the
next few years, individuals learn to use these
social tactics ﬂexibly in different social situa-
tions. For example, children aged 5 or 6 can
use deception to protect other people’s feelings
(telling “white” lies) in contrast to younger chil-
dren who mainly use deception for self-serving
reasons (e.g., to avoid punishment). A grow-
ing understanding of the self-conscious emo-
tions (such as embarrassment, guilt, and pride)
at around the same age indicates that chil-
dren are beginning to explicitly take other peo-
ple’s feelings into account in their emotional
reactions to situations.3By middle childhood,
concepts of fairness and justice show through
in an emerging tendency to share resources
The understanding of how social abilities de-
velop during late childhood and adolescence is
much less complete. Although social psychol-
ogy research on adolescence has been fruitful
since the 1970s,5research into adolescent so-
cial cognitive development, that is, the compo-
nent mental processes that underlie complex
social behaviors, is comparatively younger.6–9
However, accumulating evidence points to the
Values, Empathy, and Fairness across Social Barriers: Ann. N.Y. Acad. Sci. 1167: 51–56 (2009).
doi: 10.1111/j.1749-6632.2009.04509.x c
2009 New York Academy of Sciences.
Annals of the New York Academy of Sciences
continuing development of the ability to read
emotion in faces and of proﬁciency in taking
on other emotional perspectives (stepping into
someone else’s shoes).1
Another important social ability, the abil-
ity to sometimes decide to ignore what others
think you should do (resisting peer inﬂuence),
unfolds during the adolescent years. Steinberg
and Monahan conducted a large study in which
3600 male and female children, adolescents,
and adults completed a questionnaire asking
how likely they would be to do a variety of good,
bad, or neutral actions based on whether other
people were doing the same. It was found that
self-reported resistance to peer inﬂuence (RPI)
increased steadily between the middle and late
teens (ages 14 to 18).10 Another study was con-
ducted by Gardner and Steinberg to look at
the effects of developing RPI on risk-taking be-
havior. A laboratory study was conducted in
which adolescents (aged 13–16), youths (aged
18–22), and adults (24+) played a car-driving
video game either alone or with two friends
present.11 It was found that in the presence of
friends the adolescents (and to a lesser extent
the youths) took many more risks while driving,
for example, failing to stop at a yellow trafﬁc
light. Levels of risk taking did not increase for
adult participants if their friends were watch-
ing, and when adolescents were playing alone
they showed the same level of risk taking as
did adults. Recently, it has been shown that
this laboratory game has parallels in real life.
The Association of British Insurers reported in
2008 that teenagers are three times more likely
to have a fatal crash when driving with peers
compared to when driving alone.12
The onset of adolescence also marks a
change in patterns of social behavior. Teenagers
begin to enjoy the company of their friends
more and to spend more time with them (and
consequently less time with their families). Dur-
ing the time spent together, teenagers begin
to share their worries, secrets, and ambitions
more than they did as children. A more fully
integrated social identity emerges, with partici-
pation in relationships at different levels—from
intimate friendships and romantic attachments,
to semiﬂexible cliques of less than 10 members,
to large crowds of individuals who share distinct
fashions and interests but are not necessarily all
individually acquainted.13 At the end of ado-
lescence, an individual is expected to emerge
as a socially capable adult.
Brain Development during
Until relatively recently, it was widely held
that the brain was anatomically mature early in
life. A small number of studies published in the
late 1960s and 1970s, using post-mortem brain
samples,14,15 suggested that the brain contin-
ues to develop during adolescence. However,
it was generally assumed that changes in so-
cial behavior during the teens were a result of
hormones, social experience, and the chang-
ing social environment. These factors are un-
doubtedly important. However, neuroanatom-
ical development, which occurs throughout the
teenaged years, may also play a role.
Results from large magnetic resonance imag-
ing (MRI) studies looking at brain development
across the lifespan indicate that brain regions
involved in social cognition undergo protracted
development throughout adolescence.16–19 In
the frontal and parietal lobes, gray matter in-
creases in volume during childhood, reaching
its peak at around puberty onset. This is fol-
lowed by gray matter thinning during the re-
mainder of adolescence. This is in contrast to
basic sensory regions of the brain in which peak
gray matter volume is attained during child-
hood (for reviews, see refs. 1 and 20). It has
been suggested that the regional increases in
gray matter volume up to and around puberty
are a result of synaptic proliferation (synapto-
genesis) and that subsequent gray matter thin-
ning reﬂects the elimination or “pruning” of
synapses, as has been observed in post-mortem
brain samples.15,21,22 These changes would be
expected to result in more ﬁnely tuned neu-
ral circuits, which will respond optimally to the
Burnett & Blakemore: Adolescent Social Cognition
task in hand. Among the brain regions that
undergo these changes in gray matter volume
during the adolescent years is the prefrontal
cortex, a region involved in higher cognitive
abilities, including social cognition and the
planned control of behavior. This suggests that
the high-level abilities subsumed by these late-
maturing regions may continue to develop dur-
ing the adolescent years.
Another major neuroanatomical change that
has been observed using MRI is a linear in-
crease in white matter volume, which occurs
across the brain throughout childhood and ado-
lescence (and, indeed, into the 20s). This in-
crease in white matter volume is thought to
reﬂect ongoing maturation of neuronal axons,
for example, myelination and/or increasing ax-
onal caliber.14,23,20 These processes might be
expected to result in faster and more efﬁcient
Functional Imaging of the
Adolescent Social Brain
In the past decade, cognitive neuroscientists
have used functional MRI (fMRI) to investi-
gate brain activity during social cognition tasks
in adolescent participants. These studies have
revealed consistent differences in brain activity
between adolescents and adults.
In one of these fMRI studies, 18 adolescent
volunteers and 10 adults were scanned as they
read sentences describing situations in which
social or “basic” emotions would be felt.24 So-
cial emotions, such as embarrassment or guilt,
are emotions that require the consideration of
other people’s beliefs, feelings, or desires (their
“mental states”). For example, embarrassment
is felt when you believe that someone judges
your actions as foolish, and guilt is experienced
when you become aware that someone is suffer-
ing because of your actions. In contrast, basic
or “gut” emotions, such as pure disgust or pure
fear, are all about you—and your immediate vis-
ceral reactions. Basic emotions do not require
you to think about other people’s mental states.
In this study, components of the so-called “men-
talizing system,” comprising anterior rostral
medial prefrontal cortex (arMPFC), the pos-
terior superior temporal sulcus at the temporo-
parietal junction (pSTS/TPJ), and the ante-
rior temporal lobe (ATL), showed greater ac-
tivity in social relative to basic emotions in both
age groups (see Fig. 1, top).25,26 However, when
activity was compared between age groups, it
was found that adolescents activated arMPFC,
a brain region involved in mental state rep-
resentation,25 more strongly than did adults
for social relative basic emotions (see Fig. 1,
bottom). In contrast, adults activated left ATL
more strongly than did adolescents in this con-
trast. ATL is a brain region thought to store
social-emotional semantic information.27
Another important aspect of social cogni-
tion is the ability to understand yourself .28 This
allows you to work out how other people see
you and perhaps adjust your behavior depend-
ing on the social situation you are in. In a
recent fMRI study of self-knowledge, 12 chil-
dren (aged 10) and 12 adults underwent brain
scanning while they judged whether a series of
statements, such as “I like to read just for fun,”
applied to them.29 In another experiment, 19
teenagers and 11 adults were scanned in fMRI
as they tried to work out what they would do
in different situations (e.g., “If you were bored
on a Friday night, would you ﬁnd out what was
on at the cinema?”).30 In both experiments,
the older children and adolescents activated
arMPFC more strongly than the adults, a sim-
ilar result to that in the social emotion study.
Together, these studies collectively suggest that
adolescents use brain regions for social cogni-
tion differently than do adults, in a variety of
situations that require social understanding.
There are a number of plausible explana-
tions for these developmental differences in
functional activity within social brain regions.
One possible explanation has to do with neu-
roanatomical development. It could be the case
that adolescents activate these developing so-
cial brain regions more strongly than adults
because the less efﬁcient neural circuits need
Annals of the New York Academy of Sciences
Figure 1. Main effect of social versus basic emotion in adult (
) and adolescent (
) groups: anterior
rostral medial prefrontal cortex (arMPFC) is signiﬁcantly active in both. Graph (
) shows the negative
correlation between age and activity in arMPFC to social versus basic emotion at the coordinate for which
there was a signiﬁcant group by emotion interaction (see Burnett
more oxygen and energy to power them. This
might mean that adolescents can do just as well
as adults in certain tasks requiring social un-
derstanding, but that parts of their brain re-
quire more energy to do so. Another possibil-
ity is that adolescents are actually using differ-
ent cognitive strategies to approach social tasks.
Perhaps teenagers are still “working out” social
situations as a result of accumulating experi-
ence or developing social skills. This may mean
that they require more effortful, online, so-
cial cognitive processing. With age, processing
may become less effortful, more automatic, and
perhaps more reliant on stored social knowl-
edge. An unexplored implication of this could
be that the period of life when arMPFC and
other social brain regions are still developing—
the teens and early 20s—might be a period of
Burnett & Blakemore: Adolescent Social Cognition
particular open mindedness to new ideas and
different types of people.
Social and Nonsocial Intelligence
At this point, it is worthwhile considering
that real-life social behavior relies on many
component processes that are not speciﬁcally
social. These are the cool, forward-thinking
processes known as the “executive functions”
that allow you to exert control over your be-
havior and plan ahead. There is evidence that
some of these executive functions are still ma-
turing during the teenaged years,31 and this
may aid the development of adult social be-
havior. For example, social situations will run
more smoothly if you can regulate your imme-
diate emotional reactions (e.g., remaining calm
when somebody says something to make you
feel angry), focus on the task in hand (e.g., com-
forting a friend) by resisting temptations (e.g.,
to ask a nosy question), or keep track of several
contingent facts at once (e.g., “If he just said
this, when she said that yesterday, what she re-
ally meant was...”). These abilities, which are
useful in both social and nonsocial situations,
develop throughout the teens. At the same time,
parts of the prefrontal cortex that enable these
executive abilities continue to mature.
Conclusions and Implications
There are many factors responsible for the
complex changes in social behavior and self-
awareness that take place during the teenaged
years. Hormones, genes, and the psychoso-
cial impact of the physical changes of puberty
undoubtedly contribute, as do an individual’s
steadily accumulating experiences with differ-
ent people and social situations. And although
science has little to say on this issue, the day-to-
day decisions a teenager chooses to make must
surely alter the shape of social awareness and
behavior in the adult.
Recently, brain imaging experiments have
shown that these changes in social cognition
post puberty are also related to brain develop-
ment. In brain regions such as arMPFC, which
is involved in representing mental states, gray
and white matter continue to mature through-
out the teenaged years. These maturational
changes are thought to result in faster and more
efﬁcient brain circuits, which will respond more
appropriately to the tasks they perform. An-
other recent discovery is that activity during
social cognition tasks differs between adoles-
cence and adulthood. Speciﬁcally, adolescents
show greater activity within arMPFC than do
adults. Whether this means adolescents are ap-
proaching social situations using different cog-
nitive strategies, or whether it is a side effect of
anatomical brain development in the absence
of cognitive change, is not yet known.
Our research is funded by the Royal Soci-
ety and the Wellcome Trust. S.J.B. is a Royal
Society University Research Fellow. S.B. is
funded by the Wellcome Trust 4-year Ph.D.
program in neuroscience at University College
Conﬂicts of Interest
The authors declare no conﬂicts of interest.
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