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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Biology of romantic love | 4/14 | https://en.wikipedia.org/wiki/Biology_of_romantic_love | reference | science, encyclopedia | 2026-05-05T15:53:39.742070+00:00 | kb-cron |
=== Co-option of mother-infant bonding === Co-option is an evolutionary process whereby a given trait is repurposed to take on a new function. One example is how a number of species of fish (e.g. catfish) have co-opted their gas bladder to produce sound. Co-opted traits can be morphological, but also behavioral. Co-option has been used as an explanation of how a species can develop an evolutionary adaptation very quickly sometimes, seemingly faster than Darwinism could explain. With this process, a seemingly "new" trait can develop quickly because its structure predated the time of adaptation, only needing to be modified to function in a new way. In some cases, co-option involves one gene whose function is altered, while in other cases the co-opted gene is a duplicate and the function of the original gene is retained. The terms "co-option" and "exaptation" are closely related, but have different connotations, as exaptation refers to structural continuity when a trait takes on a new function. Adam Bode has proposed that romantic love is "a suite of adaptations and by-products" consisting of a number of interrelated systems, several of which evolved by co-opting mother-infant bonding (attraction for bonding, obsessive thinking, and attachment). The co-option theory says that the genes that regulate mother-infant bonding were recreated and took on a new function. Courtship attraction and sexual desire are "causally linked adjuncts" which were not co-opted, but were combined and modified in romantic love. The theory is based on the available human evidence, but also a literature arising from research on prairie voles that pair bonding uses the same mechanisms that mother-infant bonding uses. Academic literature has drawn a parallel between romantic love and the mother–infant dyad since the 1980s, with attachment theorists like Cindy Hazan and Phillip Shaver believing they share a common biological process. In 1981, Glenn Wilson suggested a close analogy between adult lovers and the kind of infant attachment studied by John Bowlby. In 1999, James Leckman and Linda Mayes compared features of romantic love and early parental love, finding substantial similarities. Both are altered mental states featuring preoccupations, exclusivity of focus, longing for reciprocity, and idealization of the other. The trajectories of both also share similarities, with preoccupation increasing during courtship (for romantic love) and around the time of birth (for parental love), then diminishing after a relationship is established (for romantic love) or shortly after the postpartum period (for parental love). (The use of "baby talk" by romantic lovers is another "uncanny" similarity.) In 2004, Andreas Bartels and Semir Zeki were the first to compare romantic love and maternal love with fMRI. This comparison looked at areas known to contain high densities of receptors for the attachment hormones oxytocin and vasopressin. Bartels and Zeki found precise overlap in some specific areas including the striatum (putamen, globus pallidus, and caudate nucleus) and some overlap in the ventral tegmental area, areas with dopamine, and oxytocin receptors. Each type of love was also associated with other unique activations. Notably, maternal love involved the periaqueductal gray matter, an area associated with endogenous pain suppression during intense emotional experiences such as childbirth. Two meta-analyses of fMRI experiments have also found similarities between maternal love and romantic love. A 2022 meta-analysis by Shih et al. found that both types of love were associated with the left ventral tegmental area (more associated with the pleasurable aspect of reward, or "liking"), while in addition romantic love also involved the right ventral tegmental area (more associated with reward "wanting"). In 2003, Lisa Diamond suggested that adult pair bonding is an exaptation of the affectional bond between infants and caregivers, using this to explain phenomena such as romantic friendships and "platonic" infatuations, or i.e. "romantic" passion without sexual desire. Some instances of this are reported by Dorothy Tennov in her study of "limerence" (i.e. love madness, commonly for an unreachable person), in which a younger woman who otherwise considered herself heterosexual would have this type of reaction towards an older woman. Among other examples are schoolgirls falling "violently in love with each other, and suffering all the pangs of unrequited attachment, desperate jealousy etc." (historically called a "smash"), and Native American men who seemed to fall in love with each other and form intense, but non-sexual bonds. Helen Fisher's theory that sexual desire is a separate system from romantic love and attachment is also given as theoretical evidence. Diamond argues that romantic love without sexual desire can even happen in contradiction to one's sexual orientation: because it would not have been adaptive for a parent to only be able to bond with an opposite sex child, so the systems must have evolved independently from sexual orientation. People most often fall in love because of sexual desire, but Diamond suggests time spent together and physical touch can serve as a substitute. Diamond believes the connection between romantic love and sexual desire is "bidirectional" in that either one can cause the other to occur because of shared oxytocin pathways in the brain.
=== New model === Based on contentions over evolutionary theories and Fisher's outdated neurochemical model, Bode has suggested Fisher's model, while useful and the predominant one for a time, is oversimplified and proposes five systems: