This work is from The Uniqueness of Human Milk, D.B and E.F Jelliffe, editors.
pg 997.

Not exactly what you asked for, but certainly tangentially related.

"A ..study on 60 mothers followed from the time of birth of their firstborn
until the baby was 6 months old found that significantly less neuroticism was
manifested by mothers who chose to breast feed [sic].  In addition, there was
a significant inverse relationship between the length of time breast feeding
and the extent of the mother's neuroticism."

Cornell, M.M.  Psychological variables in the mother related to infant feeding
patterns.  Dissertation Abstracts 29B3. 1969, p.3479B  Order number 4522.

From pg. 999 of same source:

"On the infra-human level, when four rhesus monkeys grew up bottle fed and
away from a mother, they developed abnormal maternal behavior when they
themselves became mothers.  Two of the mothers did eventually permit fairly
frequent nursing, but their apparently closer maternal relations were
accompanied by more violent abuse."

Harlow, H. F. and M.k. Harlow.  Social deprivation in monkeys.  Sci Amer.
207:  136, 1962.

Old stuff, I know, and less than statistically significant sample sizes, but
it is all I had.  Hope this helps!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joy Berry-Parks
LLL of Central Arkansas
Attachment Parenting Group of Arkansas
Anthropologist-in-training
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Childhood Decides."   Jean-Paul Sartre
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