being defined by the amount of limerence or non-limerence each partner contributes to the relationship. Parental bonding Attachment In 1958, British developmental psychologist John Bowlby published the paper "the Nature of the Child's Tie to his Mother," in which the precursory concepts of "attachment theory" were developed. This included the development of the concept of the affectional bond, sometimes referred to as the emotional bond, which is based on the universal tendency for humans to attach, i.e. to seek closeness to another person and to feel secure when that person is present. Attachment theory has some of its origins in the observation of and experiments with animals, but is also based on observations of children who had missed typical experiences of adult care. Much of the early research on attachment in humans was done by John Bowlby and his associates. Bowlby proposed that babies have an inbuilt need from birth to make emotional attachments, i.e. bonds, because this increases the chances of survival by ensuring that they receive the care they need. Bowlby did not describe mutuality in attachment. He stated that attachment by mother was a pathological inversion and described only behaviors of the infant. Many developmental specialists elaborated Bowlby's ethological observations. However, neither Bowlby's proximity seeking (not possible for human infants prior to walking) nor subsequent descriptions of caregiver–infant mutuality with emotional availability and synchrony with emotional modulation include the enduring motivation of attachment into adult life. The enduring motivation is the desire to control a pleasantly surprising transformation that is the route of belief in effectiveness by humans. This motivation accounts for curiosity and intellectual growth of language, mathematics and logic, all of which have an emotional base of security. Maternal bonding Of all human bonds, the maternal bond (mother–infant relationship) is one of the strongest. The maternal bond begins to develop during pregnancy; following pregnancy, the production of oxytocin during lactation increases parasympathetic activity, thus reducing anxiety and theoretically fostering bonding. It is generally understood that maternal oxytocin circulation can predispose some mammals to show caregiving behavior in response to young of their species. Breastfeeding has been reported to foster the early post-partum maternal bond, via touch, response, and mutual gazing. Extensive claims for the effect of breastfeeding were made in the 1930s by Margaret Ribble, a champion of "infant rights," but were challenged by others. The claimed effect is not universal, and bottle-feeding mothers are