The Science of Why Babies Cry More and What Parents Need to Know

You may have noticed that your baby sometimes seems calm and relaxed…and then goes through a ‘fussy’ phase, where they seem to cry no matter what you do. Do these fussy phases happen on a predictable schedule? Is it predictable for all babies…and for all parents? In this episode, we dive into the research behind the theory of the Wonder Weeks, as described in the books and app. This popular concept suggests that all babies experience predictable periods of fussiness in preparation for going through developmental ‘leaps,’ but the science behind it may be much more limited than you expect. We break down the available research, explain why babies might cry more at certain stages, and help parents understand the truth about these so-called Wonder Weeks.

What topics do we cover?

How Wonder Weeks became a popular theory
What actual research says about baby crying phases
Ways to support your baby during fussy times, whether or not Wonder Weeks apply

By the end, you’ll feel more informed about why babies cry and have a clearer idea of whether Wonder Weeks is a useful tool for understanding your baby’s needs.

If you’re expecting a baby or have a child under the age of one, you’re likely feeling a mix of excitement and overwhelm. The Right From The Start course is designed to give you the tools and confidence you need to navigate those early months with ease. Whether it’s sleep, feeding, play, or your baby’s development, this course offers evidence-based guidance that helps you understand your baby’s needs during key stages, including those fussy "Wonder Weeks" moments.

In the Right From The Start course, you’ll learn exactly how to support your baby during these challenging times, and how to create a secure, loving environment that nurtures their growth at every stage.

What you’ll get from Right From The Start:

Practical advice for sleep, feeding, and developmental milestones—especially during those Wonder Weeks!
Insights into how your baby’s brain develops, and what’s really going on during those early (and sometimes challenging) months.
Tools for managing routine activities like diapering, dressing, and communication, with strategies that align with your baby’s natural development.Beyond the knowledge, you’ll also gain access to a supportive community of parents who are navigating the same challenges, so you never have to feel alone.

Ready to get started? Click below to explore Right From The Start and prepare for a smoother, more empowered first year with your baby! Episodes Mentioned:

Books mentioned in this episode:

The Wonder Weeks by Dr. Frans Plooij and Hetty van de Rijt

Jump to Highlights: 00:03 Introduction to the Podcast and Wonder Weeks 02:19 Background on the Plooys and Their Research 05:43 Methodology and Findings of the Plooys' Study 10:20 Criticisms and Limitations of the Plooys' Study 20:11 Replication Studies and Their Findings 59:42 Conclusions and Implications References: Aldridge, J. Wayne, et al. "Neuronal coding of serial order: syntax of grooming in the neostriatum." Psychological Science 4.6 (1993): 391-395.

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Happiest Baby, Inc. (2024). Snoo smart sleeper bassinet. Author. Retrieved from: https://www.happiestbaby.com/products/snoo-smart-bassinet

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230: Do all babies have Wonder Weeks? Here’s what the research says

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