What is romantic love and why does it exist? (for now)

The genes responsible for love aren’t getting the results they once did

Humans experience a set of sensations towards other humans that we include under the term “love”.

Love to children, relatives, friends, etc. One of these types of love is especially rare, apparently rare in the animal kingdom as a whole, and contributes to humans being so particular: love for a partner. That is, the so-called romantic love.

Romantic love is probably the emotion with the greatest presence in our culture. Songs, movies, plays, paintings or sculptures deal with romantic love and its consequences. Surely we all have a pretty good idea of ​​what this kind of love is, but do we also have a definition? A recent proposal defines it as: “…a motivational state typically associated with the desire for prolonged mating with a specific individual.”

The feelings related to love are always intense like an addiction: intensely pleasant when things are going well and intensely unpleasant when things are going badly (unrequited love, jealousy, suffering after a breakup…).

Love may not seem so necessary from a biological point of view: we could reproduce with any available person without the need to fall in love (and the risk of suffering). Why love then?

Because love?
More than 60 genes associated with certain characteristics of romantic love have been described. Dozens of brain regions are also known to be involved in some way in the expression of romantic love. Hormones and endocrine factors such as dopamine or serotonin undergo changes in their levels when we are in love, acting differently in women and men.

However, the answer to why love needs to know its ultimate causes, that is, its adaptive meaning in our evolution. Any characteristic of a living being, be it anatomical, physiological or behavioral, that appears in the majority of the individuals of a species, is likely to have evolved thanks to its positive effect on reproduction.

And what could love have contributed to reproduction? The most probable answer has to do with the pair bond and the collaboration of the male in caring for the young. Love makes individuals focus their sexual interest on a specific partner.

The most important consequence is that, when it is reciprocated, it promotes the fidelity of both, with the double effect of certainty of paternity for the male and his collaboration in the care of the offspring. In other words, it favors monogamy during the time that it remains as a feeling between the members of the couple.

more immature hatchlings
In the evolutionary history of the human lineage, romantic love must have developed after the appearance of stable mates and the collaboration of the father in caring for the young. This must have occurred after the emergence of the genus Homo, when species with less sexual dimorphism began to appear, denoting a more monogamous type of mating compared to the more polygynous one that preceded it.

Adaptations that arose in the human evolutionary lineage, such as the reduction in the size of the pelvis due to the optimization of bipedal locomotion, together with the increase in brain size, promoted that mothers gave birth to more immature offspring. As a consequence, the health and survival of these neonates began to depend heavily on the combined efforts of both parents. When the couple must cooperate to produce and raise common children, romantic love acquires its meaning.

Animals are also loving and jealous
In many animal species, the collaboration of the couple is necessary to raise the young. It is true that this occurs more frequently in birds and not so much among mammals. We don’t know for sure to what extent partner relationships in other animal species are accompanied by feelings similar to romantic love. But there are lifelong bonds, apparently affectionate behaviors, obsessive monitoring or protection of the partner accompanied by physiological changes.

Infidelity in monogamous couples is also frequent in many animals studied. Genetics has shown us, for example, that many of the offspring of monogamous birds that we find in a nest are not daughters of the official father.

In many animals, sexual behaviors towards individuals of the same sex are also frequent, although, again, there is no evidence that there is something similar to love as it occurs in humans between people of the same sex.

Undoubtedly, the biological bases of romantic love between people of the same sex deserve to be dealt with in detail in another specific article.

A future without romantic love?
In today’s society, disconnected from natural processes and with contraceptive methods that allow us to decide on the reproductive results of our sexuality, in addition to having options to reproduce without the need for love and even without a partner, it is evident that the genes responsible for love do not they are getting the result they had before.

Perhaps this human trait, like so many others, is maintained thanks to phylogenetic inertia, that is, the fact that genetic material tends to be copied with little modification from one generation to the next.

Apart from the trends in social influences that are added to the biological background, this situation of weakness in natural selection, in itself, increases random variability in biological traits and therefore the loss of the predominant pattern. Could the type of love we know today tend to disappear over time, or at least to coexist with new variations and possibilities?

Perhaps it is risky to say that a world without romantic love awaits us in which people are not especially motivated to form stable relationships. Or, who knows, it may already be happening.