We used to have a baby that cried a lot. We couldn't quite understand why. Every time she cried we kept on distracting or comforting her hoping she'd grow out of it, as books on baby care promised.
Stressed but unrelenting, I was determined to find a solution. Article after article, book after book I found the roots of our problem: our baby was extremely overtired.
From all the research I've done I learned three important things: (1) a 4-month-old needs to sleep 14-15 hours a day. (2) a 4-month-old cannot stay awake for more than 1.5-2 hours. (2) A 4-month-old needs to go to sleep for the night at 7pm! Having read four books on infant sleep I realized this was the three things they all agreed on. Understanding this made a huge difference for us and our baby.
The cause of our crying was very clearly explained in the book by Marc Weissbluth Healthy Sleep Habits, Happy Child. What often happens is when the baby wants to sleep, the parents interfere. The baby starts crying because she wants to sleep. What do the parents do? They try to distract her with toys or by taking her to a different room, or some other type of stimulation. My mother-in-law, for instance, was convinced that the baby wants a bath, while the bath, being a very stimulating experience for my baby, was the last thing she needed. As a result of our misreading of her cues, our baby grew more and more tired and her cries escalated into desperate screams. Our baby was a lot smarter than we were. She needed to sleep and she kept on trying to tell this to us. We were ignoring her pleas, what else could she do other than scream? Instead of trying to distract her, we should have respected her need to sleep. At the first signs of drowsiness we should have put her to bed.
Ok, we figured out that our baby needed to sleep. But bedtime has always been associated with crying. This is where the bedtime routine came in. (BTW, this is another one of those things that all baby-sleep books as well as scientific papers agree on). As soon as our baby showed signs of tiredness, I decided that we should put her into her sleeping back and into the crib, so she'd have a chance to rest and fall asleep. Of course she doesn't fall asleep by herself yet (wishful thinking), but hopefully one day she'll learn. We let her stay in her crib by herself until she starts crying. Then we come in and comfort her, and when that is not enough, we pick her up and rock her to sleep.