Whatever did all these parents do before some but job came up with these ridiculous ideasGoogle ‘wonder weeks’ - it’s basically a theory that all babies go through periods of development or ‘leaps’ at the same weeks old age so you can predict how their moods might change and what new skills they will develop.
The skills predictions have been pretty accurate for my baby but it’s not at all to say it’s all happened in that one week that the theory claims, that’s how it’s become so popular I think though. With the moods there’s a placebo effect of putting any mood changes down to the leap that’s helpful, it becomes very unhelpful when parents look out for it and believe it’s a leap rather than something that needs investigating or stick to it so stringently they worry if the child hasn’t ‘leapt’.