It matters what we think about evolution. In many situations, nothing matters more. My wife, Connie, just spent the past several hours browsing Internet news and blogs on the Jamie Lynn Spears fiasco. She files this guest post:

Jamie Lynn Spears (16-year-old sibling of Britney) for three years has played the smart, good-girl lead on Nickelodeon's popular tweens television show, Zoey 101. On December 18, she (and her mom) announced to the world that she was pregnant -- about 3 months pregnant.

Now many parents are faced with not only having to help their tween (and even pre-tween) girls deal with their grief and anger that their idol has fallen, but also helping them come through this ordeal better prepared to face the intimacy challenges that they themselves will surely face.

Here is where an understanding of our evolved quadrune brain can be of enormous help.

Chapters 8 through 10 of Thank God for Evolution! (a pdf of which can be downloaded for free here) is a great way to quickly absorb not only the science but also the parenting implications of the profound insights born of evolutionary psychology and evolutionary brain science.

For this blog post, we offer a color version of the 2-part illustration that appears on page 135, along with its caption:

OUR QUADRUNE BRAIN. Our deepest, oldest brain components (and behavioral drives) reflect our ancient reptilian heritage -- what might be called, our Lizard Legacy. Next, and wrapping around the reptilian core, is our paleomammalian brain, the limbic system, which is the seat of emotions -- our Furry Li'l Mammal. Superimposed on these two structures is our newer, neomammalian brain: our neocortex, which is our incessantly talkative Monkey Mind. Last to evolve is the section of neocortex at our forehead. With a left side and a right side, these are our frontal lobes -- the seat of our sense of purpose, our Higher Porpoise.

Okay, so what does this have to do with Zoey (er, Jamie Lynn Spears)? Everything!

Briefly, Jamie Lynn Spears got pregnant because the powerful instincts for sex that are embedded in the Lizard Legacy part of our brain, and which are awakened by the surge of hormones that mark puberty, got the best of her better judgment — that is, her Higher Porpoise.

And let's give her the benefit of the doubt. Let's assume that she really was committed, deeply committed, to acting in accordance with her values regarding intimacy — whether those values might have been outright sexual abstinence or perhaps sexual responsibility, i.e., commitment to use contraceptives and STD protection every time.

When her Furry Li'l Mammal's enormous desire for romance and nurturing touch teamed up with her (or maybe just his) Lizard Legacy's compelling desire for copulation, it is no surprise that Jamie Lynn's commitments succumbed to lapses in judgment for a very simple reason: the frontal lobes of the human brain do not fully develop until our early twenties!

That is why all teens — be they from conservative families or from liberal families — absolutely require support systems that, in effect, can serve as their external frontal lobes. This, from the 17 October 2004 issue of The New York Times:

Teenagers in stressful situations . . . are not going to act like adults. Their brains can't handle it. . . . "This is why kids who are good kids, who know right from wrong, sometimes do stupid things," says Dr. David Fassler, a psychiatrist in Burlington, Vt., and a spokesman for the American Psychiatric Association on this issue [whether to ban the death penalty for murderers under the age of 18]. "They act on impulse."

How, then, do most teenagers survive adolescence without harming themselves or winding up in jail? Good parenting is one reason, Baird says. "The people around you are like an external frontal cortex," she says.

If you've never heard that parents and other adults responsible for teens must serve as a stand-in for the as-yet under-developed executive function of their brains (their frontal lobes, prefrontal cortex, or "Higher Porpoise"), it is because until very recently scientists were clueless about one crucial fact of brain development. Before 2004, scientists assumed that the human brain was fully developed by around the time of puberty. Teens made bad choices because they held the wrong values, lacked experience, or were subject to harmful social influences of peers. But in 2004, scientists announced the discovery of this alarming fact: the part of the human brain that is absolutely crucial for staying out of trouble does not mature until our early twenties!

This, from page 159 of Thank God for Evolution!:

From an "unintelligent design" perspective, one could argue that God blundered by arranging for the human body to develop its secondary sexual characteristics a full decade before the frontal lobes (Higher Porpoise) of the human brain become fully operative.

Hence, it really does matter what we think about evolution. In this situation, perhaps nothing matters more.

Conservative parents and guardians of teens will respond to the news of our evolved brains in a variety of ways that suit their values and traditions. Liberal parents and guardians will do likewise. But both groups will be well served to step up to the plate on this matter right now.

Evolution can no longer be ignored by either group.

Jamie Lynn, please hear this: Breakthroughs can emerge from breakdowns. By the time your baby is born and you step up to the responsibilities of parenthood, I hope parents everywhere are breathing a sigh of relief that, thanks to you, they are now equipped with far better insights and tools for safely guiding their own teens through this challenging life transition. And that my dear, will be a great gift to the world.

Note: In 2005, the U.S. Supreme Court, cited the 2004 scientific research on frontal lobes in teens in ruling that youths under 18 who committed crimes could not be sentenced to the death penalty.