What if everything you’ve been told about infant sleep is rooted in a century-old theory that dismissed love as unscientific? Are “cry-it-out” techniques really helping families, or just fueling a billion-dollar parenting industry built on exhaustion and guilt?
In this eye-opening episode of The Science Chick Report, the first of a special two-part series, Dr. Kathleen Kendall-Tackett takes a clear, evidence-based look at the world of sleep training, challenging both the parenting industry and the pediatric establishment. She traces its origins to the behaviorist movement of the 1920s, which urged parents not to comfort or emotionally engage with their babies in the name of “science.”
Dr. Kendall-Tackett contrasts this outdated view with attachment theory and evolutionary biology, showing that responsive caregiving is not spoiling—it is essential for survival and healthy development. Through a critical review of multiple studies, she asks whether sleep training truly helps babies sleep better or simply teaches them to stop signaling distress.
If you are a new parent, healthcare provider, or anyone who has ever been told to let a baby “cry it out,” this episode will empower you to question conventional wisdom and make informed, compassionate choices for your family.
In This Episode:
(00:00) Introduction: why sleep training needs a second look
(01:06) The business of baby sleep and the modern parenting dilemma
(02:13) Pediatricians and the promotion of cry it out
(03:23) Historical and theoretical foundations: Behaviorism
(05:30) Parenting without emotion: lessons from John B. Watson
(06:32) The rise of attachment theory after World War II
(08:31) Why infant crying is evolutionary, not manipulative
(10:37) What the latest research really says about cry it out
(12:55) Do babies really sleep better or just cry less?
(15:34) When cry it out backfires: findings from Canada and beyond
(18:20) Why ignoring babies raises cortisol and risks brain development
(21:10) The hidden costs of “successful” sleep training
(23:02) What studies from China and Australia reveal about sleep and maternal mood
(26:17) The two-way relationship between maternal depression and infant sleep
(28:22) Final reflections: toward a more responsive approach
Notable Quotes:
(01:17) “Infants crying at night is probably one of the hardest things to deal with when you're dealing with a newborn.” – Dr. Kathleen Kendall-Tackett
(11:38) “Excessive crying is associated with maternal depression, anxiety, and parental exhaustion, but it also can possibly disrupt attachment and increase the risk of abuse.” – Dr. Kathleen Kendall-Tackett
(22:31) “These poor little mute babies, still distressed, but they've learned not to signal.” – Dr. Kathleen Kendall-Tackett
Resource and Links
The Science Chick Report
The Science Chick Report
Dr. Kathleen Kendall-Tackett
Mentioned
Breaking the Silence" by Mariette Hartley
Bathory & Thomas Paulus (2017) – Pediatric Sleep Recommendations
Wolke (2017) – Infant Crying and Parental Sensitivity
Build & Invoke (2020) – Cry It Out in First-Time Mothers
Davis & Kramer (2021) – Ecological Critique of Cry It Out
Middlemiss et al. (New Zealand Study) – Cortisol Synchrony in Sleep Training
Sapolsky (1996, Science) – Cortisol and Brain Health
Chinese Meta-Analysis (2020) – Infant Sleep Interventions
Australian Cohort Study – Maternal Depression and Infant Sleep