Again, CIO is not the only (or best for baby) method. I see alot of advice that has to do with bottles, where did the OP state she was formula feeding? If you are bottle feeding, I would say it is bad advice to suggest mixing the formula with cereal to keep baby full. The baby NEEDS the nutrition from breastmilk or formula, just as often as baby is hungry.
OP- if you are willing to do research on the "Ferber method" why not research Dr.Sears? He offers much more peaceful solutions for parents of infants than this crying stuff. Also, there is a book called "our babies, ourselves" that is very enlightening. It was written by an anthropologist, and offers a different view of the whole infant sleep thing.
There have been several studies that show that when a baby cries, for any reason, their hormone cortisol rises. Cortisol is your stress hormone, the fight or flight hormone.Repeated increase in cortisol can actually change a baby's brain chemistry.
We are mammals after all. A cry, of any kind, is to let the mother know that the baby needs something. If left untended to in the wild, young that cry out without being helped are at greater risk of predators. An infant NEEDS comfort, needs touch, needs to be near their caregiver(s).... why do you think infants in the neonatal hospitals that are held/ massaged/ touched more often grow faster and stronger?
It is a biological response to tend to your baby. That is why many mothers experience the rapid beating of their heart, the overwhelming urge to get to their baby. It is biological. We are born to care for our young. Only when that bond is disturbed either at birth or in the early attachment months after birth can this natural response be disturbed.
Only in the US and Western cultures do we try to force independence on an infant. It is sad that babies can't be babies and know that the adults around them can be trusted and will tend to their needs.
When a baby cries and cries and no one comes, they give up. People think, "oh, she needed to cry to fall asleep" - not so... the baby is quiet because their trust has been betrayed and they know no one will come when they are hungry, lonely or scared.
this is coming from a mother of two children, who (as infants) never kept me up all night. Not once. I am a well-rested new mom. I am glad my children have never been left in a room to cry themselves to sleep, and it makes me sad to think of any baby going through that.