How risk-taking changes a teenager's brain

Why do teenagers sometimes make outrageous, risky choices? Do they suddenly become reckless, or are they just going through a natural phase? To find out, Kashfia Rahman -- winner of the Intel International Science and Engineering Fair (and a Harvard freshman) -- designed and conducted an experiment to test how high school students respond to and get used to risk, and how it changes their still-developing brains. What she discovered about risk and decision-making could change how we think about why teens do what they do.

Have you ever tried
to understand a teenager?

It's exhausting, right?

You must be puzzled by the fact
that some teens do well in school,

lead clubs and teams

and volunteer in their communities,

but they eat Tide Pods
for an online challenge,

speed and text while driving,

binge drink and experiment
with illicit drugs.

How can so many teens
be so smart, skilled and responsible --

and careless risk-takers at the same time?

When I was 16,

while frequently observing
my peers in person

as well as on social media,

I began to wonder why so many teens
took such crazy risks.

It seems like getting a certificate
from DARE class in the fifth grade

can't stop them.

(Laughter)

What was even more alarming to me

was that the more they exposed
themselves to these harmful risks,

the easier it became for them
to continue taking risks.

Now this confused me,

but it also made me incredibly curious.

So, as someone with a name

that literally means
"to explore knowledge,"

I started searching
for a scientific explanation.

Now, it's no secret
that teens ages 13 to 18

are more prone to risk-taking
than children or adults,

but what makes them so daring?

Do they suddenly become reckless,

or is this just a natural phase
that they're going through?

Well neuroscientists
have already found evidence

that the teen brain
is still in the process of maturation --

and that this makes them
exceptionally poor at decision-making,

causing them to fall prey
to risky behaviors.

But in that case,
if the maturing brain is to blame,

then why are teens
more vulnerable than children,

even though their brains
are more developed than those of children?

Also, not all teens in the world
take risks at the same level.

Are there some other underlying
or unintentional causes

driving them to risk-taking?

Well, this is exactly
what I decided to research.

So, I founded my research
on the basis of a psychological process

known as "habituation,"

or simply what we refer to
as "getting used to it."

Habituation explains how our brains
adapt to some behaviors,

like lying, with repeated exposures.

And this concept inspired me
to design a project

to determine if the same principle

could be applied to the relentless
rise of risk-taking in teenagers.

So I predicted that
habituation to risk-taking

may have the potential to change
the already-vulnerable teenage brain

by blunting or even eradicating

the negative emotions
associated with risk,

like fear or guilt.

I also thought because they
would feel less fearful and guilty,

this desensitization would lead them
to even more risk-taking.

In short, I wanted to conduct
a research study

to answer one big question:

Why do teens keep making
outrageous choices

that are harmful
to their health and well-being?

But there was one big obstacle in my way.

To investigate this problem,

I needed teenagers to experiment on,

laboratories and devices
to measure their brain activity,

and teachers or professors to supervise me
and guide me along the way.

I needed resources.

But, you see, I attended
a high school in South Dakota

with limited opportunity
for scientific exploration.

My school had athletics,

band, choir, debate and other clubs,

but there were no STEM programs
or research mentors.

And the notion of high schoolers

doing research or participating
in a science fair was completely foreign.

Simply put, I didn't exactly
have the ingredients

to make a chef-worthy dish.

And these obstacles were frustrating,

but I was also a stubborn teenager.

And as the daughter
of Bangladeshi immigrants

and one of just a handful
of Muslim students

in my high school in South Dakota,

I often struggled to fit in.

And I wanted to be someone
with something to contribute to society,

not just be deemed
the scarf-wearing brown girl

who was an anomaly
in my homogenous hometown.

I hoped that by doing this research,

I could establish this

and how valuable scientific exploration
could be for kids like me

who didn't necessarily
find their niche elsewhere.

So with limited research opportunities,

inventiveness allowed me to overcome
seemingly impossible obstacles.

I became more creative in working
with a variety of methodologies,

materials and subjects.

I transformed my unassuming school library

into a laboratory

and my peers into lab rats.

(Laughter)

My enthusiastic geography teacher,

who also happens to be
my school's football coach,

ended up as my cheerleader,

becoming my mentor
to sign necessary paperwork.

And when it became logistically impossible

to use a laboratory
electroencephalography,

or EEG,

which are those electrode devices
used to measure emotional responses,

I bought a portable EEG headset
with my own money,

instead of buying the new iPhone X

that a lot of kids my age
were saving up for.

So finally I started the research

with 86 students,
ages 13 to 18, from my high school.

Using the computer cubicles
in my school library,

I had them complete a computerized
decision-making simulation

to measure their risk-taking behaviors
comparable to ones in the real world,

like alcohol use, drug use and gambling.

Wearing the EEG headset,

the students completed the test
12 times over three days

to mimic repeated risk exposures.

A control panel on the EEG headset

measured their various
emotional responses:

like attention, interest,
excitement, frustration,

guilt, stress levels and relaxation.

They also rated their emotions

on well-validated
emotion-measuring scales.

This meant that I had measured
the process of habituation

and its effects on decision-making.

And it took 29 days
to complete this research.

And with months of frantically
drafting proposals,

meticulously computing data
in a caffeinated daze at 2am,

I was able to finalize my results.

And the results showed
that habituation to risk-taking

could actually change a teen's brain
by altering their emotional levels,

causing greater risk-taking.

The students' emotions
that were normally associated with risks,

like fear, stress, guilt and nervousness,

as well as attention,

were high when they were first
exposed to the risk simulator.

This curbed their temptations
and enforced self-control,

which prevented them
from taking more risks.

However, the more they were exposed
to the risks through the simulator,

the less fearful, guilty
and stressed they became.

This caused a situation

in which they were no longer able to feel

the brain's natural
fear and caution instincts.

And also, because they are teenagers
and their brains are still underdeveloped,

they became more interested and excited
in thrill-seeking behaviors.

So what were the consequences?

They lacked self-control
for logical decision-making,

took greater risks

and made more harmful choices.

So the developing brain alone
isn't to blame.

The process of habituation
also plays a key role in risk-taking

and risk escalation.

Although a teen's willingness to seek risk

is largely a result of the structural
and functional changes

associated with their developing brains,

the dangerous part
that my research was able to highlight

was that a habituation to risks

can actually physically
change a teen's brain

and cause greater risk-taking.

So it's the combination
of the immature teen brain

and the impact of habituation

that is like a perfect storm
to create more damaging effects.

And this research can help parents
and the general public

understand that teens aren't just
willfully ignoring warnings

or simply defying parents by engaging
in increasingly more dangerous behavior.

The biggest hurdle they're facing
is their habituation to risks:

all the physical, detectable
and emotional functional changes

that drive and control and influence
their over-the-top risk-taking.

So yes, we need policies
that provide safer environments

and limit exposures to high risks,

but we also need policies
that reflect this insight.

These results are
a wake-up call for teens, too.

It shows them that the natural
and necessary fear and guilt

that protect them from unsafe situations

actually become numb when they
repeatedly choose risky behaviors.

So with this hope to share my findings
with fellow teenagers and scientists,

I took my research

to the Intel International
Science and Engineering Fair, or ISEF,

a culmination of over 1,800 students

from 75 countries,
regions and territories,

who showcase their cutting-edge
research and inventions.

It's like the Olympics of science fair.

(Laughter)

There, I was able to present my research
to experts in neuroscience and psychology

and garner valuable feedback.

But perhaps the most
memorable moment of the week

was when the booming speakers
suddenly uttered my name

during the awards ceremony.

I was in such disbelief
that I questioned myself:

Was this just another "La La Land" blunder

like at the Oscars?

(Laughter)

Luckily, it wasn't.

I really had won first place

in the category "Behavioral
and Social Sciences."

(Applause)

Needless to say,

I was not only thrilled
to have this recognition,

but also the whole experience
of science fair that validated my efforts

keeps my curiosity alive

and strengthens my creativity,

perseverance and imagination.

This still image of me
experimenting in my school library

may seem ordinary,

but to me, it represents
a sort of inspiration.

It reminds me that this process
taught me to take risks.

And I know that might sound
incredibly ironic.

But I took risks realizing

that unforeseen opportunities
often come from risk-taking --

not the hazardous,
negative type that I studied,

but the good ones,

the positive risks.

The more risks I took,

the more capable I felt of withstanding
my unconventional circumstances,

leading to more tolerance,
resilience and patience

for completing my project.

And these lessons
have led me to new ideas

like: Is the opposite
of negative risk-taking also true?

Can positive risk-taking
escalate with repeated exposures?

Does positive action
build positive brain functioning?

I think I just might have
my next research idea.

(Applause)