The Pseudoscience Hiding in Your Child’s Daycare
The Daycare Debate: What Science Actually Says About Your Child’s Brain
The Two Sides of the Story
On one side: Commentators warn that daycare harms children’s developing brains.
- Mikhaila Fuller (daughter of Jordan Peterson) told 1.3 million podcast followers that daycare affects children in "pretty nasty ways" and warns against "traumatizing" kids
- Erica Komisar, a psychoanalyst, claimed on Diary of a CEO that daycare causes "pathological defenses" from separation "trauma"
- She stated: "It’s so bad for their brain… and it’s been known to increase aggression"
On the other side: Major institutions call daycare essential for development and society.
- The European Commission says preschool "lays the foundations for later success in life"
- The World Bank claims it helps "countries be more productive" in the global economy
- Governments worldwide spend billions on daycare as an "investment in future workforce members"
- Politicians from Obama to Biden have claimed massive returns: $7 for every $1 spent, reduced crime, better graduation rates, stronger families
The Stress Hormone Controversy
What Critics Say About Cortisol
Important: Cortisol is often called "the stress hormone," but that’s only half the story.
The claim: Daycare skeptics point to studies showing children in daycare have:
- Higher cortisol levels in saliva
- Cortisol that rises throughout the day (instead of falling like normal)
What the Science Actually Shows
Cortisol isn’t a villain—it’s essential for life. Without it, you would die. Here’s what you need to know:
- Normal pattern: Cortisol peaks when you wake up, then declines through the day
- Short spikes happen from exercise, socializing, and excitement—not just stress
- Chronically stressed people can actually have lower cortisol, not higher
- Daycare cortisol spikes could mean stress—OR excitement from novelty and social complexity
The measurement problem: Cortisol can change 10x in a single day. Results vary by:
- Age
- Time since eating
- Recent exercise
- Day-to-day natural variation
Key Takeaway: Current studies may be too small and noisy to detect a real signal. We simply don’t have reliable enough data to draw firm conclusions.
The Brain Development Claims
Komisar’s Amygdala Theory
On Diary of a CEO, Komisar claimed:
- Separation stress makes the amygdala (emotion center) "become active precociously"
- It then "shrivels up and burns out" from managing stress too early
- This supposedly causes chronic anxiety, depression, and ADHD
The Reality Check
| Claim | Evidence Status |
|---|---|
| Amygdala activates early from daycare stress | No research exists |
| Amygdala "shrivels and burns out" | Pure speculation |
| Smaller amygdala = caused by trauma | Unknown—could be born that way |
| This causes anxiety/depression/ADHD | No causal evidence |
Bottom line: Komisar is a mainstream commentator (Wall Street Journal, Good Morning America), but her specific brain claims have zero scientific backing.
The "Miracle Cure" Claims
What Politicians Promise
- Obama (2013): "$7 return for every $1 spent"—higher than roads, comparable to clean water in developing nations
- Hillary Clinton: "Evidence is overwhelming" for economic development
- Joe Biden: Universal pre-K for "best-educated workforce in the world"
- Bill de Blasio: Creates "a more fair and just society"
- UK Government: Helps babies "achieve better in school" and "future success on the labour market"
What the Best Studies Actually Show
The Perry & Abecedarian Projects (1960s-70s):
- Intensive programs for very disadvantaged Black children in segregated America
- Included free healthcare + home visits—not just daycare
- Small samples (~100 kids each)
- Imperfect statistics by modern standards
- Showed higher earnings, lower arrest rates decades later
Modern Large-Scale Studies (1990s-2000s):
- Academic boost: Small gains in literacy/numeracy at preschool age
- Fade-out: Benefits disappear within a few years of elementary school
- Social skills: Mixed—some studies show better cooperation, others show more behavioral problems
- Clearest winners: Children from disadvantaged backgrounds (poverty, low parental education, instability)
The Tennessee RCT (Rare Randomized Trial):
- Standardized statewide preschool
- Followed kids through high school
- Same pattern: Helped disadvantaged kids initially, effects washed out over time
Critical Distinction: Perry/Abecedarian were intensive, multi-service interventions for extremely deprived children. Universal daycare today is a totally different thing. Extrapolating those results is "audacious" at best.
Why This Debate Matters
The Hidden Cost of Fear-Mongering
When we raise the bar for "good enough" parenting:
- Fewer children are born — South Korea (intensive tutoring culture) has 0.8 children per woman—world’s lowest
- Parents feel needless guilt — Couples delay parenthood until one can stay home, or feel guilty using daycare
- Wrong priorities — Families stress over "perfect" preschool choice instead of what actually works for them
The Honest Scientific Consensus
After decades of research: If daycare had large, lasting impacts—positive OR negative—we would know by now. On a population level, any effects are too small to be obvious.
Summary
- Cortisol data is real but meaning is unclear—could be stress, could be excitement
- Brain damage claims (amygdala "burnout") are pure speculation with zero evidence
- Miracle benefit claims ($7 return, crime reduction) come from tiny, outdated studies of intensive programs—not regular daycare
- Modern evidence shows small, temporary academic gains that fade out by elementary school
- Disadvantaged children benefit most, but effects still don’t persist long-term
- Observational studies can’t prove causation—families choosing daycare differ in many ways
- Best randomized trial (Tennessee) confirms: fade-out is real
- Parents should choose what works for their family without guilt or fear
FAQ
1. Does daycare cause permanent brain damage?
No. Claims about amygdala "shriveling" or permanent trauma have zero scientific evidence. They are speculative theories not supported by any research.
2. Is it true that daycare raises stress hormones?
Yes, but… Cortisol levels are higher in daycare children and rise through the day. However, cortisol isn’t "bad"—it’s essential for life. The rise could reflect excitement and stimulation, not distress. We can’t tell the difference from cortisol alone.
3. Will my child do better in life if they go to preschool?
Maybe slightly, temporarily. Studies show small academic boosts at school entry, but these typically fade within a few years. The clearest benefits are for children facing poverty or family instability.
4. Are the famous "$7 return on investment" claims true?
Not for regular daycare. That number comes from two 1960s-70s studies (Perry/Abecedarian) of intensive, multi-year programs with healthcare and home visits for extremely disadvantaged children. Regular universal pre-K hasn’t shown those returns.
5. Should I feel guilty about using daycare?
Absolutely not. The science shows no large, lasting harms for typical children. Families should make choices based on their values, finances, and circumstances—not fear-based claims from either side of the political debate.