Anne you say
Young kids are smarter than we tend to give them credit for

In the early stages.. nurturing is programmed into an infant.
The hugs the wrapping warmly and as the weeks go by how the baby fits into the birth family..its survival mode

Much damage is done when nurturing is not given...and a baby who does not cry or express their needs may be one whose needs are not being met..and they can give up.

The message is...dont exist...
this is an extreme example I know but I was taught this treatment for the baby can bring mental health issues later..
so medics are alerted for post natal depression happening..

so the child who reaches for reassurance is a smart child.