Human newborns are much more emotionally and psychologically developed than they are often given credit for! Research has shown that an infant recognizes the mother who has given birth to him, through her scent, voice, and heartbeat. It is, therefore reasonable to believe that an infant also notices when his birth mother is not there. There is a theory called the "Primal Wound", which holds that children who are placed for adoption have a very difficult time ever learning to trust again, or overcome fears of being rejected or abandoned. While I think the severity and lack of potential for this to be overcome is often exaggerated, I do believe that something to that order exists and that, therefore, it is especially important for an infant who is placed for adoption to be with the adoptive parents as soon as possible and that adoptive parents should take very seriously the need for to do everything in their power to quickly assure the baby that, although the mother he has known is no longer there, she has provided him with someone else on whom he can depend for the love and care that he needs.
There are many things adoptive parents can do to facilitate this process. Spending lots of time holding, rocking and singing to the baby, carrying him in a sling or pack, infant massage, etc., are among the things that are helpful.
Nurturing the baby at the breast can help develop trust and security in a baby in an especially timely manner. There have been moms and babies who have nursed without any breastmilk production and been totally delighted by the experience, including a woman who'd had a double mastectomy and breast reconstruction! With an understanding and appreciation of the nurturing benefits of adoptive nursing, there simply is no room for failure!