The Wonder Weeks

What are The Wonder Weeks?

Let’s start here. Have you ever woken up to the sound of your baby crying and thought, “That’s it. This week, I’m taking some action. This week we’re going to start teaching that baby some sleep skills.”

Then, sometime in the morning when your third cup of coffee starts to kick in, you find yourself second guessing the idea. Maybe you feel like things aren’t that bad yet, or you get into the, “I knew what I was getting into when I decided to have a baby,” mindset. Or maybe someone told you that this wasn’t really the right time, since your baby was just about to go through a big developmental milestone, and makes a reference to The Wonder Weeks.

If you’re not familiar with it, the husband-and-wife team of Frans Plloji, a behavioural scientist, and Hetty van de Rijt, an educational psychologist developed The Wonder Weeks

What are The Wonder Weeks?

The idea goes something like this. Starting at five weeks old and continuing through the 20-month mark, babies go through 10 mental development stages or “leaps”.

“Sunny weeks,” during which baby is typically happy and agreeable are followed by “stormy weeks,” during which baby’s fussy and inconsolable due to the neurological development. And then baby masters the new skill or developmental milestone during the “wonder week” and baby goes back to being “sunny” again.

Many parents absolutely swear by this book and its popular companion app. (The original book has sold over 2 million copies across 25 languages.) Some people even claim that it tracks their little one’s development to the day as opposed to the week.

Others will tell you that it’s built on flawed science. And that what the authors are doing is essentially a form of paediatric astrology, making vague predictions based on norms and averages, and reassuring its followers that good things are perpetually just over the horizon.

A couple of things to consider. The Wonder Weeks builds on a 1992 study that used a sample size of just 15 participants. And it relied almost exclusively on questionnaires filled in by the mothers as opposed to direct observation from the researchers.

Dr. Plooij offered a counter argument for the small sample size, stating that if you find a behaviour in two individuals, “then you already have proof that the phenomenon exists and is not due to luck or chance.” Not terribly convincing, is it?

1990s: New research into The Wonder Weeks

In the mid 1990s, Dr. Plooij’s Ph.D. student, Dr. Carolina de Weerth, attempted to replicate the findings from the original study with an even smaller sample size of four babies, and failed to reach the same conclusions. Dr. de Weerth claims that Plooij pressured her to find correlations that supported his original research, and when she refused, he attempted to prevent the publication of her findings. (A claim that Plooij denies.) The University of Groningen didn’t renew Plooj’s contract following the incident, and he subsequently left academia altogether.

Suffice it to say, there’s still controversy and debate over its legitimacy.

If parents take comfort in being able to predict when their baby will be cranky, I think that’s just fine. Parents need all the support they can get and I say take your mental health boosts where
you can.

What does it mean for my baby?

The potential downside I see is that parents might put too much belief in the accuracy of The Wonder Weeks, and develop some unnecessary concerns if things don’t go according to schedule. As parents, we don’t need unrealistic expectations based on inaccurate research, telling us that their little one has failed to hit a developmental milestone “on time”.

The reality is, that babies develop at their own pace. The majority of developmental milestones have quite a long window of time for what’s considered average. A number of months in fact. So really, where babies follow the Wonder Weeks to the day, it’s most likely a coincidence rather than science.

When babies are working on new skills, such as rolling, crawling or walking, it can affect their mood, and their sleep. If they’re mastering a skill and get frustrated or “stuck” you might notice more “stormy” behaviour. This may affect their sleep as they practice these new skills in their cot!

However, they could also feel “stormy” because they’re overtired, or bored, or less tolerant because they’re tired. After all, life is easier for all of us when we’re well rested.

In my experience, for the majority of babies, once they’re sleeping well, they’ll handle developmental changes more easily. And with their sleep becoming less disrupted.

So please don’t let the Wonder Weeks be your reason to put off making sleep changes. Sleep is one of the most important factors for our babies’ growth and development, after all! If you have a healthy baby, you can make sleep changes!

If you’re looking for support in making changes to your baby’s sleep, visit my Slumber School Programme for 6 – 18 month olds. Or find out more about my 1 – 1 packages.

Studies cited

Hedwig H.C. Van De Rijt-Plooij PhD & Frans X. Plooij PhD (1992) Infantile regressions: Disorganisation and the
onset of transition periods

Weerth, C.D. (1998). Emotion-related behaviours in infants: a longitudinal study of patterns and variability. s.n.