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Kashfia Rahman: How risk-taking changes a teenager's brain
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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.
Kashfia Rahman - Psychology researcher
Kashfia Rahman studies psychology, cognitive science and global health policy at Harvard University. Full bio
Kashfia Rahman studies psychology, cognitive science and global health policy at Harvard University. Full bio
Double-click the English transcript below to play the video.
00:12
Have you ever tried
to understand a teenager?
to understand a teenager?
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It's exhausting, right?
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You must be puzzled by the fact
that some teens do well in school,
that some teens do well in school,
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lead clubs and teams
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and volunteer in their communities,
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but they eat Tide Pods
for an online challenge,
for an online challenge,
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speed and text while driving,
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binge drink and experiment
with illicit drugs.
with illicit drugs.
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How can so many teens
be so smart, skilled and responsible --
be so smart, skilled and responsible --
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and careless risk-takers at the same time?
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When I was 16,
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while frequently observing
my peers in person
my peers in person
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as well as on social media,
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I began to wonder why so many teens
took such crazy risks.
took such crazy risks.
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It seems like getting a certificate
from DARE class in the fifth grade
from DARE class in the fifth grade
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can't stop them.
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(Laughter)
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What was even more alarming to me
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was that the more they exposed
themselves to these harmful risks,
themselves to these harmful risks,
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the easier it became for them
to continue taking risks.
to continue taking risks.
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Now this confused me,
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but it also made me incredibly curious.
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So, as someone with a name
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that literally means
"to explore knowledge,"
"to explore knowledge,"
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I started searching
for a scientific explanation.
for a scientific explanation.
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Now, it's no secret
that teens ages 13 to 18
that teens ages 13 to 18
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are more prone to risk-taking
than children or adults,
than children or adults,
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but what makes them so daring?
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Do they suddenly become reckless,
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or is this just a natural phase
that they're going through?
that they're going through?
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Well neuroscientists
have already found evidence
have already found evidence
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that the teen brain
is still in the process of maturation --
is still in the process of maturation --
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and that this makes them
exceptionally poor at decision-making,
exceptionally poor at decision-making,
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causing them to fall prey
to risky behaviors.
to risky behaviors.
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But in that case,
if the maturing brain is to blame,
if the maturing brain is to blame,
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then why are teens
more vulnerable than children,
more vulnerable than children,
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even though their brains
are more developed than those of children?
are more developed than those of children?
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Also, not all teens in the world
take risks at the same level.
take risks at the same level.
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Are there some other underlying
or unintentional causes
or unintentional causes
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driving them to risk-taking?
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Well, this is exactly
what I decided to research.
what I decided to research.
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So, I founded my research
on the basis of a psychological process
on the basis of a psychological process
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known as "habituation,"
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or simply what we refer to
as "getting used to it."
as "getting used to it."
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Habituation explains how our brains
adapt to some behaviors,
adapt to some behaviors,
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like lying, with repeated exposures.
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And this concept inspired me
to design a project
to design a project
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to determine if the same principle
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could be applied to the relentless
rise of risk-taking in teenagers.
rise of risk-taking in teenagers.
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So I predicted that
habituation to risk-taking
habituation to risk-taking
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may have the potential to change
the already-vulnerable teenage brain
the already-vulnerable teenage brain
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by blunting or even eradicating
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the negative emotions
associated with risk,
associated with risk,
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like fear or guilt.
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I also thought because they
would feel less fearful and guilty,
would feel less fearful and guilty,
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this desensitization would lead them
to even more risk-taking.
to even more risk-taking.
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In short, I wanted to conduct
a research study
a research study
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to answer one big question:
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Why do teens keep making
outrageous choices
outrageous choices
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that are harmful
to their health and well-being?
to their health and well-being?
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But there was one big obstacle in my way.
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To investigate this problem,
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I needed teenagers to experiment on,
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laboratories and devices
to measure their brain activity,
to measure their brain activity,
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and teachers or professors to supervise me
and guide me along the way.
and guide me along the way.
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I needed resources.
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But, you see, I attended
a high school in South Dakota
a high school in South Dakota
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with limited opportunity
for scientific exploration.
for scientific exploration.
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My school had athletics,
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band, choir, debate and other clubs,
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but there were no STEM programs
or research mentors.
or research mentors.
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And the notion of high schoolers
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doing research or participating
in a science fair was completely foreign.
in a science fair was completely foreign.
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Simply put, I didn't exactly
have the ingredients
have the ingredients
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to make a chef-worthy dish.
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And these obstacles were frustrating,
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but I was also a stubborn teenager.
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And as the daughter
of Bangladeshi immigrants
of Bangladeshi immigrants
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and one of just a handful
of Muslim students
of Muslim students
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in my high school in South Dakota,
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I often struggled to fit in.
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And I wanted to be someone
with something to contribute to society,
with something to contribute to society,
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not just be deemed
the scarf-wearing brown girl
the scarf-wearing brown girl
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who was an anomaly
in my homogenous hometown.
in my homogenous hometown.
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I hoped that by doing this research,
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I could establish this
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and how valuable scientific exploration
could be for kids like me
could be for kids like me
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who didn't necessarily
find their niche elsewhere.
find their niche elsewhere.
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So with limited research opportunities,
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inventiveness allowed me to overcome
seemingly impossible obstacles.
seemingly impossible obstacles.
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I became more creative in working
with a variety of methodologies,
with a variety of methodologies,
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materials and subjects.
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I transformed my unassuming school library
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into a laboratory
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and my peers into lab rats.
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(Laughter)
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My enthusiastic geography teacher,
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who also happens to be
my school's football coach,
my school's football coach,
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ended up as my cheerleader,
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becoming my mentor
to sign necessary paperwork.
to sign necessary paperwork.
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And when it became logistically impossible
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to use a laboratory
electroencephalography,
electroencephalography,
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or EEG,
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which are those electrode devices
used to measure emotional responses,
used to measure emotional responses,
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I bought a portable EEG headset
with my own money,
with my own money,
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instead of buying the new iPhone X
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that a lot of kids my age
were saving up for.
were saving up for.
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So finally I started the research
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with 86 students,
ages 13 to 18, from my high school.
ages 13 to 18, from my high school.
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Using the computer cubicles
in my school library,
in my school library,
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I had them complete a computerized
decision-making simulation
decision-making simulation
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to measure their risk-taking behaviors
comparable to ones in the real world,
comparable to ones in the real world,
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like alcohol use, drug use and gambling.
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Wearing the EEG headset,
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the students completed the test
12 times over three days
12 times over three days
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to mimic repeated risk exposures.
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A control panel on the EEG headset
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measured their various
emotional responses:
emotional responses:
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like attention, interest,
excitement, frustration,
excitement, frustration,
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guilt, stress levels and relaxation.
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They also rated their emotions
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on well-validated
emotion-measuring scales.
emotion-measuring scales.
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This meant that I had measured
the process of habituation
the process of habituation
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and its effects on decision-making.
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And it took 29 days
to complete this research.
to complete this research.
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And with months of frantically
drafting proposals,
drafting proposals,
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meticulously computing data
in a caffeinated daze at 2am,
in a caffeinated daze at 2am,
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I was able to finalize my results.
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And the results showed
that habituation to risk-taking
that habituation to risk-taking
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could actually change a teen's brain
by altering their emotional levels,
by altering their emotional levels,
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causing greater risk-taking.
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The students' emotions
that were normally associated with risks,
that were normally associated with risks,
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like fear, stress, guilt and nervousness,
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as well as attention,
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were high when they were first
exposed to the risk simulator.
exposed to the risk simulator.
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This curbed their temptations
and enforced self-control,
and enforced self-control,
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which prevented them
from taking more risks.
from taking more risks.
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However, the more they were exposed
to the risks through the simulator,
to the risks through the simulator,
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the less fearful, guilty
and stressed they became.
and stressed they became.
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This caused a situation
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in which they were no longer able to feel
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the brain's natural
fear and caution instincts.
fear and caution instincts.
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And also, because they are teenagers
and their brains are still underdeveloped,
and their brains are still underdeveloped,
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they became more interested and excited
in thrill-seeking behaviors.
in thrill-seeking behaviors.
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So what were the consequences?
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They lacked self-control
for logical decision-making,
for logical decision-making,
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took greater risks
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and made more harmful choices.
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So the developing brain alone
isn't to blame.
isn't to blame.
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The process of habituation
also plays a key role in risk-taking
also plays a key role in risk-taking
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and risk escalation.
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Although a teen's willingness to seek risk
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is largely a result of the structural
and functional changes
and functional changes
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associated with their developing brains,
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the dangerous part
that my research was able to highlight
that my research was able to highlight
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was that a habituation to risks
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can actually physically
change a teen's brain
change a teen's brain
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and cause greater risk-taking.
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So it's the combination
of the immature teen brain
of the immature teen brain
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and the impact of habituation
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that is like a perfect storm
to create more damaging effects.
to create more damaging effects.
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And this research can help parents
and the general public
and the general public
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understand that teens aren't just
willfully ignoring warnings
willfully ignoring warnings
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or simply defying parents by engaging
in increasingly more dangerous behavior.
in increasingly more dangerous behavior.
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The biggest hurdle they're facing
is their habituation to risks:
is their habituation to risks:
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all the physical, detectable
and emotional functional changes
and emotional functional changes
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that drive and control and influence
their over-the-top risk-taking.
their over-the-top risk-taking.
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So yes, we need policies
that provide safer environments
that provide safer environments
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and limit exposures to high risks,
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but we also need policies
that reflect this insight.
that reflect this insight.
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These results are
a wake-up call for teens, too.
a wake-up call for teens, too.
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It shows them that the natural
and necessary fear and guilt
and necessary fear and guilt
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that protect them from unsafe situations
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actually become numb when they
repeatedly choose risky behaviors.
repeatedly choose risky behaviors.
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So with this hope to share my findings
with fellow teenagers and scientists,
with fellow teenagers and scientists,
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I took my research
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to the Intel International
Science and Engineering Fair, or ISEF,
Science and Engineering Fair, or ISEF,
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a culmination of over 1,800 students
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from 75 countries,
regions and territories,
regions and territories,
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who showcase their cutting-edge
research and inventions.
research and inventions.
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It's like the Olympics of science fair.
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(Laughter)
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There, I was able to present my research
to experts in neuroscience and psychology
to experts in neuroscience and psychology
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and garner valuable feedback.
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But perhaps the most
memorable moment of the week
memorable moment of the week
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was when the booming speakers
suddenly uttered my name
suddenly uttered my name
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during the awards ceremony.
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I was in such disbelief
that I questioned myself:
that I questioned myself:
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Was this just another "La La Land" blunder
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like at the Oscars?
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(Laughter)
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Luckily, it wasn't.
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I really had won first place
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in the category "Behavioral
and Social Sciences."
and Social Sciences."
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(Applause)
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Needless to say,
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I was not only thrilled
to have this recognition,
to have this recognition,
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but also the whole experience
of science fair that validated my efforts
of science fair that validated my efforts
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keeps my curiosity alive
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and strengthens my creativity,
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perseverance and imagination.
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This still image of me
experimenting in my school library
experimenting in my school library
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may seem ordinary,
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but to me, it represents
a sort of inspiration.
a sort of inspiration.
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It reminds me that this process
taught me to take risks.
taught me to take risks.
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And I know that might sound
incredibly ironic.
incredibly ironic.
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But I took risks realizing
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that unforeseen opportunities
often come from risk-taking --
often come from risk-taking --
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not the hazardous,
negative type that I studied,
negative type that I studied,
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but the good ones,
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the positive risks.
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The more risks I took,
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the more capable I felt of withstanding
my unconventional circumstances,
my unconventional circumstances,
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leading to more tolerance,
resilience and patience
resilience and patience
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for completing my project.
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And these lessons
have led me to new ideas
have led me to new ideas
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like: Is the opposite
of negative risk-taking also true?
of negative risk-taking also true?
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Can positive risk-taking
escalate with repeated exposures?
escalate with repeated exposures?
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Does positive action
build positive brain functioning?
build positive brain functioning?
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I think I just might have
my next research idea.
my next research idea.
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(Applause)
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ABOUT THE SPEAKER
Kashfia Rahman - Psychology researcherKashfia Rahman studies psychology, cognitive science and global health policy at Harvard University.
Why you should listen
The daughter of Bangladeshi immigrants, Kashfia Rahman grew up as a minority in a homogenous community in Brookings, South Dakota. When she was in high school, she noticed her peers frequently succumbing to risky behaviors as well as the ruthless burdens of stress and peer pressure. Working directly on peers at her school, she dedicated research to studying the neuroscientific and psychological processes underlying these behaviors, and how the environment plays a role in emotion-processing and cognitive functioning in teens. With the hopes of raising awareness to minimize the potential for engaging in harmful behaviors, she took her research to the Intel International Science and Engineering Fair, a culmination of 1,800 students from over 75 countries sometimes described as the "Olympics of science fairs." For her research projects, she was awarded first place in her category as well as was recognized by the National Institutes on Drug Abuse and the American Psychological Association.
Rahman is also a Google Science Fair finalist and a Regeneron Science Talent Search Scholar. Featured in the National Geographic documentary Science Fair for her dedication to science research, Rahman is passionate about sharing her pathway to research and strives to expand the platform for marginalized and disempowered voices. She is also interested in bridging the gender and racial gap in the field of STEM and in advocating for healthy environments to improve teens' behavioral and mental health.
Kashfia Rahman | Speaker | TED.com