The sudden intensification of communal sharing relationships evokes kama muta. That is, kama muta is evoked by sudden ‘love,’ whether the love is romantic, parental, or patriotic, or whether it consists of team spirit and pride. Typically, what intensifies communal sharing are acts of consubstantial assimilation – acts that make participants’ bodies alike. This may consist of giving birth, nursing, feeding, commensalism, affectionate touch or cuddling, loving sex, mixing body fluids in ritual blood brotherhood, circumcision, rhythmic synchronous movement such as dance or drill, or belief in shared ‘blood’ or genes. The proclivity for kama muta likely evolved from maternal bonding, then pair-bonding, and now functions in humans to forge adaptive communal sharing bonds of all sorts. The communal sharing relationships that are adaptively beneficial depend on the culture, so the kama muta proclivity must be attuned to cultural implementations of communal sharing. We can recognize kama muta by the combination of five aspects: characteristic appraisal, lexical labels, positive valence, a certain set of sensations, and motivation to devote oneself to, and commit to, communal sharing relationships.