It makes us eager for meeting new potential mates. Many named security, closeness and trust as the common denominators for their feelings in a longstanding partnership. Researchers now believe that even this deep bond is a hormonal predilection, instilled in us to safeguard long-term family planning. Close bonding, the third crucial emotion, has to do with oxytocin and vasopressine. These are substances in the brain that impart the feeling of deep affection.
Biochemists are in fact amazed at oxytocin's manifold effects.
In research laboratories like those here at the University of Hamburg they discovered that it is a veritable all-round substance in reproduction. And es affects behavior as well as emotions. It seems to be involved wherever pressing reproduction events happen to be unfolding. For example, oxytocin is produced when breastmilk is released, but also during childbirth. Men also produce it, e.g. during ejaculation.