Quoting Emily Ann Anita Sobczyk:" It's not always such a bad thing. I know that at a certain age frame you do want them to learn how to ... [snip!] ... are okay and have everything the need then its not entirely wrong. At least that is what I have read in certain baby books."
the CIO method is bad for brain cells. this was not always known, but now it is. In some older baby books they might not point out that the CIO method is very bad for babys because they did not always know.
But lucky for use the medical community has learned about
how extended crying affects adrenaline and cortisol the stress hormones. Science has also found that when developing brain tissue is exposed to these hormones for prolonged periods these nerves won’t form connections to other nerves and will degenerate.
Simply put CIO causes brain damage, and now we know.