Please Explain: Teenagers' Brains

Friday, December 02, 2011

In October, neuroscientists Sandra Aamodt and Sam Wang were on Please Explain to discuss how a young children’s brains develop. And this week they return to discuss the brains of adolescents and teenagers—from sleep problems, gender differences, behavior issues, learning disabilities, and hormones. They investigate myths about brain development and sort through the factors that matter—and those that don’t—in brain development from childhood to college. They’re the co-authors of Welcome to Your Child's Brain: How the Mind Grows from Conception to College.

How well do you know your child's brain? Take this quiz!


Sandra Aamodt and Sam Wang

Comments [15]

Sam Wang from Princeton, NJ

Steve Capra, iti is not an inference, but a factual observation. There is peer-reviewed literature that demonstrates that among boys who prefer stereotypically girl-like toys, about half turn out to be gay.

The probable reason for this is that there are hormone-driven mechanisms that set up both sex-specific toy preference, as well as sexual preference. If such mechanisms go in a different direction in early development, then both preferences can be switched.

Dec. 02 2011 07:23 PM
Sam Wang from Princeton, NJ

Sam Wang here. Some answers to these very good questions follow.

Amy from Manhattan: Sex hormones act on the brain at two very different times in development: before birth, and during puberty, which is often defined by breast development and first menstruation in girls, and muscle growth and voice deepening in boys. For both, there are other signs. Puberty usually occurs between ages 11 and 13.

What's interesting is that although we spent a lot of time talking about sex differences, the brain is undergoing much larger changes before puberty: between the ages of four and ten a tremendous amount of remodeling is going on.

Michele Viehl, you raise an interesting point. However, I disagree with you that Sandra and I have different views on gender differences. After all, we are discussing material that we co-researched and co-wrote. Perhaps you bring your own interpretations in listening to a male and female scientist.

Elizabeth from Queens, I am not sure what to say about contraception. However, since adolescents are more impulsive yet cognitively aware of consequences, probably they should have contraception handy, as opposed to going out and getting it.

Amanda from NY, NY, you are correct. Also, it is important to think of these differences as being mostly small, with the few exceptions that we mentioned, such as spatial rotation and toy preference. Also, it is likely that the differences can be shaped by experience. In addition to our book, Welcome To Your Child's Brain, Lise Eliot (also a neuroscientist, like us) writes about the latter possibility in her book Pink Brain, Blue Brain.

John Rock from Somerset, I think you did not understand our point. As we said on the air, and in our book too, brains are biological devices shaped by many generations of evolution. Brains develop starting from a genetic program, then receive (and seek out) events in the environment to develop. In any event, you'll find much to agree with in Welcome To Your Child's Brain.

Sigrid from NYC, the environment properly defined includes both social context and physical stimuli such as nutrition and stress. The recent study you cite is interesting, but note that the authors report the effect as being a subtle one.

Thanks to all for listening today.

Dec. 02 2011 03:38 PM
Steve Capra from New York

Your guests who just spoke on brain development were helpful. However, I take issue with their comments that half of the male children who prefer feminine-identified toys grow up to be gay. This implies that gay men self-identified overwhelmingly as feminine when they were children and, by extension, adults.

Could you asks your guests to expand on this inference?

Dec. 02 2011 03:26 PM
Amy from Manhattan

Your guests keep referring to "puberty". I know the ages vary per child, but what it this generally accepted age range referrred to as "puberty", and at what age does the hormone influx peak?

Dec. 02 2011 01:54 PM
elizabeth from Queens

What are the implications for what research shows about impulse control in adolescents, ESP boys, for sex education. Are these findings taken into consideration when people advocate giving adolescents contraception and expecting them to form meaningful sexual relationships?

Dec. 02 2011 01:54 PM
Michele Viehl

As a developmental psychologist, I'm intrigued by the pattern in this interview: Sam's vs Sandra's perspectives seem weighted. Sam seems almost biased toward gender differences. I wonder whether such male researcher bias is something Sandra has noticed among neuroscientists. One hopes neuroscientists are more objective than psychologists. Yet such a bias does remind me of the case of zoologists studying a particular bird:

For at least 100 years, this bird was cited as evidence of monogamy's evolutionary basis. But only in the late 20th century did field observers actually look inside those nests: they found these "mated for life" pairs all consisted of 2 females!!

We really need to do a MUCH better job staying on top of our cultural gender biases, if we're ever to untangle this nature-nurture debate re gender.

Dec. 02 2011 01:49 PM

Thanks for the heads up! We've fixed the link.

Dec. 02 2011 01:48 PM
Amanda from New York, NY

It's important to remember that the research that reflects gender differences in certain areas represents overall averages. This means that an individual man may be better than an individual women in an area where women tend to excel, and inversely as well, a woman may be better than an individual man, or even most men, in an area where men in general score higher.

Dec. 02 2011 01:46 PM
Batya from CT

Hi! The Teenage Brain quiz page is not working.

Dec. 02 2011 01:43 PM

Please ask the guests to speak to issue of teenagers' increased need for sleep. My 16 year old daughter says she feels like a "freak" because she can easily sleep 10-11 hour nights over a weekend but says her friends don't. she goes to bed before 10 pm on school nights but says her friends can stay up to midnight routinely. What are the facts?

Dec. 02 2011 01:42 PM
Pam Gockley

What happens in the development of antisocial p d brains, narcissist p d brains, etc? It seems to begin rather early.

Dec. 02 2011 01:42 PM

How can this research help those of us who are dealing with one of these "novelty seeking" post pubertal teenage boys who are putting themselves in increasing danger?

Dec. 02 2011 01:42 PM
john rock from Somerset

The idea that 'almost nothing is biologically determined in humans' is surely off base. Girls don't 'learn' to value their looks unless Cleopatra was in the same class 2500 years ago. We are animals, driven by instincts amassed from millenia of hunter gatherer evolution.

Dec. 02 2011 01:39 PM
Bernard from Bronx

Black girls generally have fewer problems with body image. Why is that?

Dec. 02 2011 01:37 PM
Sigrid from NYC

There's lots more than genes and culture, recent study found that girls exposed to soy early show less "feminine" behavior.;jsessionid=F5068E1CEEF2A5795F8645B4C1F5E81A?articleURI=info%3Adoi%2F10.1289%2Fehp.119-a525b

Dec. 02 2011 01:32 PM

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