Unexplainable – “Diary of a Teenage Brain, Part 2” (December 10, 2025)

Vox | Hosts: Julia Longoria, Bird Pinkerton

Episode Overview

In this episode, the Unexplainable team dives deep into the Adolescent Brain Cognitive Development (ABCD) Study—a groundbreaking, decade-long research project tracking the brains and lives of over 11,000 American children from around age nine into young adulthood. Through a mix of interviews with researchers and a participant, the team explores what the study is uncovering about teenage risk-taking, substance use, and the very real limits and promises of trying to "understand" the teenage brain.

Key Discussion Points & Insights

1. The ABCD Study: “The Boyhood of Brain Studies”

• What is it?
  The ABCD study is a massive, decade-spanning project following almost 12,000 children as they grow up, using interviews, MRIs, behavioral tests, and biological sample collection to piece together how adolescent brains develop.
• Raul Gonzalez’s Role:
  Raul Gonzalez, a professor and principal investigator at the Florida International University (FIU) site, has dedicated over 10 years to the study, which was originally designed to identify risk factors for drug use and addiction.
• Comparison to film “Boyhood”
  "The ABCD study is the boyhood of adolescent brain studies. They've followed the same cohort of nearly 12,000 kids across the US for almost a decade." (Julia Longoria, 03:07)

2. How the Study Works—And Why It’s So Ambitious

• Multi-Site and Comprehensive:
  21 research sites, annual data collection including MRIs, behavioral tasks, questionnaires about home and social life, and even collections of hair, teeth, and urine samples.
  "We can get a really great understanding of who they are, what their life is like, from how their brain works to what's their family situation like, their personality, mental health assessments… also looking at brain shapes, neuroimaging data…." (Raul Gonzalez, 05:01)
• Unexpected Data:
  “We also collect baby teeth.” (Raul Gonzalez, 05:31)
  Used to track exposure to toxins.

3. The Evolving Focus—More Than Drugs

• Expanded Research Questions:
  While substance use was the primary driver, the study quickly expanded to cover sleep, screen time, physical activity, mental health, obesity, and more.
• Field Buy-In:
  "It's been a wonderful slippery slope." (Raul Gonzalez, 06:18)
  Researchers from across disciplines found the dataset so invaluable, they lobbied to add their own questions.

4. Getting Honest Answers From Teens—A Challenge

• Recruitment and Retention:
  The episode highlights the challenge of getting teens to consistently participate and respond candidly for a decade. As Julia Longoria waits in her car for a participant to arrive, she quips, "Still waiting," (09:07) illustrating the unpredictability of adolescent engagement.
• Interview with Briana (ABCD Participant):
  Briana, now 18, reflects on being a participant since age nine.
  • She’s in it, at first, because her mom signed her up; she later appreciates learning about her own brain and the incentives ("I remember one time I won like $35, which was a lot." – Briana, 15:25).
  • She describes the range of questions—from the innocuous (“how many times I use my phone?”) to the more personal (“Do you have a boyfriend?”) to substance use questions (“They asked me if I smoked once. And I was like, I’m nine.” – Briana, 16:39).

5. The Limits of Self-Report & How Science Fights Back

• Truthfulness of Answers:
  Raul Gonzalez acknowledges: "We have evidence that everybody is not telling us the truth. And that's not unique to this particular study..." (Raul Gonzalez, 18:15)
  • To compensate, the study uses hair toxicology—about 10% of participants who denied substance use tested positive for drugs.
    • “10% are liars.” (Julia Longoria, 19:03)
    • “Or they may be waiting to tell us the truth.” (Raul Gonzalez, 19:06)

6. Early Findings From the Study

• Risk Factors for Early Substance Use:
  The richest predictors so far are psychosocial and family variables—not brain scans.
  • "The psychosocial factors and the kind of family variables were better, or like more useful predictors of trying substances than the brain structure stuff." (Bird Pinkerton, 21:22)
  • “Not that the neuroimaging is meaningless… but its explanatory value… is not as strong…” (Raul Gonzalez, 21:35)
• Context for Early Substance Use:
  Raul clarifies that experimenting with substances does not doom a teen:
  • “Oh no, absolutely not. Most people have a full drink do not develop an alcohol use disorder.” (Raul Gonzalez, 22:19)

7. The Hope: A Roadmap for Intervention

• Looking for Actionable Patterns:
  By tracking kids across similar backgrounds—e.g., sleep habits, screen time, family life—the hope is to spot factors that can be changed or targeted with interventions.
  • “If the data showed that the kids who slept more tended to have fewer problems with alcohol, then maybe for kids with this kind of profile, getting more sleep could be an effective intervention.” (Bird Pinkerton, 23:45)
  • “That’s exactly right. And we can even go one step further…” (Raul Gonzalez, 24:12)

8. The Human Side—Parenting and Risk

• Raul as a Parent:
  Raul has a 16-year-old and, despite his expertise, shares the universal challenge of judging which risky behaviors are concerning and which are just “normal.”
  • “Oh, well, yes. I mean, I think I struggle like any parent, but boy, I sure want her to make plenty of mistakes while I’m still around. And I can still kind of catch her before she falls or… let her fall and experience natural consequences from mistakes and learn. Mistakes are opportunities to learn.” (Raul Gonzalez, 25:52)
  • “I cannot stop my daughter from engaging in risky behaviors. And then also, you know, why would I? Risk is an inherent part of the human condition.” (Raul Gonzalez, 26:12)
• Limits of Science for Individuals:
  Even as the study builds a “better roadmap,” Raul points out, “There's too much serendipity involved… These are things that can move the health of an entire population. But then applying some of these group-level findings to the individual… it may not work out exactly how it worked out in the paper for that one kid.” (Raul Gonzalez, 27:01-27:25)

Memorable Quotes

• “It was going to be the study that anybody would ever want to do, but nobody would ever have the resources to do.” – Raul Gonzalez (04:36)
• “Baby teeth are really cool because they're like the barks of a tree and they can tell us about exposure to all sorts of heavy metals and toxins from birth.” – Raul Gonzalez (05:35)
• “10% are liars.” – Julia Longoria (19:03)
  “Or they may be waiting to tell us the truth.” – Raul Gonzalez (19:06)
• “Most people who have a full drink do not develop an alcohol use disorder. The vast majority of people that smoke a joint or consume cannabis do not develop a cannabis use disorder.” – Raul Gonzalez (22:19)
• “Boy, I sure want her to make plenty of mistakes while I'm still around. And I can still kind of catch her before she falls... Mistakes are opportunities to learn.” – Raul Gonzalez (25:52)
• “Risk is an inherent part of the human condition. What I can do is try to mitigate the risks and hope that in the face of risk we can still get great outcomes.” – Raul Gonzalez (26:12)

Notable Timestamps

• 03:07: Julia introduces the ABCD as the “boyhood” of brain studies
• 05:01: Raul details the breadth of ABCD’s data collection
• 13:49: Briana describes how her mother signed her up for the study
• 15:25: Briana talks about memory games and the allure of $35 in prize money
• 16:39: Briana’s surprise at being asked about smoking at age 9
• 19:03: Raul admits that 10% of participants test positive for substances they deny using
• 21:22: Bird explains that psychosocial variables out-predict brain scans for substance experimentation
• 22:19: Raul reassures that trying substances is not a ticket to addiction
• 23:45: Bird and Raul discuss use of the data for actionable interventions
• 25:52: Raul on letting his teenage daughter make mistakes: “Mistakes are opportunities to learn.”

Conclusion

This episode offers a rare glimpse inside one of the most ambitious neuroscience experiments of our time, mixing scientific explanation with personal narrative. Through expert voices and first-hand experience, it reveals both the promise and the very real limitations of peering into teenage minds – reminding listeners that while large-scale data may light the way for public health, the “art of parenting” will always require not just data, but human judgment, patience, and humility.

Next in the series:
Stay tuned for the follow-up episode, which will focus on what we might learn from teens themselves.

For more about the ABCD study and findings, visit the study’s website (as mentioned by the hosts at 27:52).