" The baby crying tip seems kinda weird, too. If a baby won't stop crying, there's likely something wrong. Making odd noises might distract for a while. But I'm not convinced that babies harbor any nostalgic feelings about being in the womb, or the sounds to be heard there."

It does work though,

It may sound weird but a lot of times babies cry because they are overstimulated or just tired. The noise is familiar and relaxing to them and causes them to calm down long enough to either fall asleep or just take a breath. Sometimes just taking a baby out of the room they're in works too because there might just be to much going on for them to process and handle at one time. Being a baby can be stressful LOL