Bonding is an imprinting process (where an instinct is turned on at the right time, in the right conditions) where there is an emotional investment in another person. It is usually without their awareness that a friendship of a sort, was forming. Bonding implies that comfort and encouragement are going to be ours (with the right person), and it all begins with the interactions of our parents, emotionally.
Many research studies and the theory of attachment and bonding depict bonding as a two-way process between parent and child. 1 Only in recent years has it been studied regarding bonding in adult life or romance. 2 However, the mutual, two-way process described in today's research can be confusing to the layman and laywoman, and confused with another imprinting process that is different in nature, called, "attachment." In the Romantic Dynamics lexicon, we want to see bonding as that emotional connection felt by, and expressed by a person in a parenting role.
In adult life, this can represent the emotions of tender care and protection we feel toward a friend. It is also seen in romance, when one of the two in a couple temporarily takes a parenting style role (helping from the point of ample resources), and the other person is in a dependent or child role (receiving love, emotion, and help.)
In a mature, adult romance, it is normal to occasionally vary between being equals in resources, being independent, and being in the more dependent, child role, versus being the teammate and partner who has more strength at the moment and provides them. In fact, we often see the word, "bond" or the word, "bonding" occur in descriptions of friendship.
We know friendship to be an area of romance and socializing that pertains to the mammalian brain, to love, self-esteem and happiness in being together, more than seeing it refer to desire or the instincts of the reptilian brain. So you can see a difference between attachment and bonding in the form of attachment being a more desire-related, and therefore, reptilian-brained process.