Why do we treat teenagers like ticking time bombs? For decades, the dominant story about young people has been that their underdeveloped brains make them impulsive and irrational—leaving adults no choice but to control them or shield them from consequences.

Developmental psychologist David Yeager challenges this “neurobiological incompetence” model. Keep reading to learn how the model misses the mark and leads us astray.

The Neurobiological Incompetence Model

Conventional wisdom in Western culture says that young people are basically impulsive, bad at thinking for themselves, and unable to make good choices. According to developmental psychologist David Yeager, this “neurobiological incompetence model” is flawed and leads to ineffective ways of relating to adolescents.

In his 2024 book 10 to 25, Yeager explains that the model rests on 20th-century scientific findings that the adolescent brain lacks a fully developed prefrontal cortex (the part of the brain that governs decision-making). Studies have also shown that the limbic system (the brain’s seat of emotion) is more active in young people than in adults. These findings have led to the idea that young people can’t control themselves, so they need adults to tell them what to do. In other words, we assume that young people are neurobiologically incompetent—their brains don’t yet work as well as adults’ do, so they can’t behave properly.

(Shortform note: By calling this the “neurobiological incompetence model” Yeager points out how we’ve medicalized young people’s development by treating their normal human experiences as medical conditions. He traces the origin of this to a sloppy interpretation of the ancient Greek allegory where a charioteer (reason) has to control wild horses (passions). We tend to interpret this as an explanation of young people’s emotionality. But Plato, who created the allegory, didn’t seem to intend this. Rather, the allegory was about his notion of the human soul as a three-part composite striving toward truth, goodness, and beauty—one good horse, one bad horse, and one charioteer trying to coordinate them.)

Incompetence-Based Mentoring Approaches

Yeager is a developmental psychology professor at UT Austin who earned his PhD from Stanford’s School of Education. Before entering academia, he taught middle school. In his book 10 to 25, he identifies two main schools of thought based on the view that young people are neurobiologically incompetent:

• Authoritarian mentorship assumes that, since young people are incompetent, they need to be managed with a firm, uncompromising hand. This approach enforces strict expectations of performance without giving much support in return.
• Permissive mentorship assumes that, since young people are incompetent, they need to be protected from hardship. This approach gives lots of support while lowering standards so that no one experiences too much stress or pressure.

(Shortform note: Yeager’s terms are “enforcer” and “protector,” but we’ve swapped them out to align with those commonly used in psychology—”authoritarian parent” and “permissive parent.” These two approaches aren’t the full picture, either. In Grit, Angela Duckworth (a colleague of Yeager’s) lays out four styles—authoritarian, permissive, neglectful, and authoritative—and contrasts them along two axes: demanding/undemanding and supportive/unsupportive. Duckworth writes that the best style is authoritative, which mixes discipline with emotional support. She says that parents who use this style raise children who get better grades, are more confident, and have better mental health.)

According to Yeager, both authoritarian and permissive mentorship styles fall short, but for different reasons:

• The authoritarian approach fails because it treats young people disrespectfully, which tends to cause rebellion, frustration, or other unproductive behaviors. Research on nagging illustrates this effect: When parents simply tell their kids what to do and expect obedience, it triggers hormone reactions in their children that make them upset with their parents and more likely to disobey.
• The permissive approach fails for the opposite reason: It gives young people too much leeway, which teaches them that they don’t have to respect the teacher or mentor and that they don’t have to try to earn recognition. In other words, too many unearned gold stars create kids who are a bit spoiled. Yeager saw this firsthand when he worked at an orphanage. Because the kids had been through a lot of hardship, he treated them leniently. But, because of this, they learned to walk all over him, knowing he’d clean up after their messes and wouldn’t hold them accountable.

(Shortform note: The two failed mentorship styles Yeager mentions also reflect the history of parenting styles, which weren’t formalized before the turn of the 20th century. Then, John B. Watson’s book Psychological Care of Infant and Child taught the authoritarian style we recognize today—with strict rules such as ”children should be seen and not heard” and a heavy emphasis on obedience without explanation. Not until the 1960s, with Benjamin Spock’s Baby and Child Care, did more parents swing toward a permissive style. Later, we saw the rise of helicopter parenting, another distinct style in which parents are overinvolved in their children’s lives. Some argue that both permissive and authoritarian parents can be helicopter parents.)

Learn More About the Model & Its Alternatives

In 20 to 25, Yeager argues that the neurobiological incompetence model fails because it misunderstands what actually drives young people. To discover the approach he recommends instead, check out the book and Shortform’s guide to it.