The reason why humans fall in love is evolutionary. From a biological point of view, that set of feelings that we call love They have allowed the human species to reproduce and prosper. Se knows, in fact, that romantic love and all the activities associated with it lead to the acquisition and maintenance of certain behaviors, necessary to create an affective bond between the partners and take care of the offspring together.
The emotions we experience when we are in love they modify our behavior, push us to commit to a relationship and bond emotionally both with the couple and, in case of being conceived, with the offspring. It's not romantic at all, is it?
The partner as an adaptive response
If sexual desire is the means to procreate, falling in love has created the concept of "family." Find a partner and create a relationship A more or less lasting affective relationship with him is nothing more than a "maneuver" to give the unborn future a safe and serene environment in which to grow. Human-like behaviors have also been observed in other species, for example, some birds choose a specific partner to mate with and care for their young together.
The adaptive response...
The couple bond evolved as a adaptive response to the need for greater investment by parents in the upbringing of young people. By adaptive response we understand the ability of living organisms to change their metabolic, physiological and behavioral processes, allowing them to adapt to the conditions of the environment in which they live.
In other words, romantic relationships and their persistence are an evolutionary necessity in species in which biparental care of offspring was essential. Unlike most animal species, women usually give birth to one child at a time. The latter is not self-sufficient for several years after birth and that is why the presence of adult caregivers is necessary - who can be members of the family nucleus, that is, both parents.
The organ of love – the brain
The brain, and not the heart, is responsible for the varied series of emotions that we experience from the moment we fall in love until we suffer from a love that has ended. This is all due to specific molecules, neurotransmitters that act on the brain testosterone and estrogen, dopamine, serotonin, adrenaline, norepinephrine, oxytocin and vasopressin, which are commonly called "hormones of love and attachment". These come into play in different phases of falling in love which are basically three: desire, attraction and attachment.
If we fall in love, we wish
Imagine being in a disco, while you look at the crowd your attention is captured by a single person, something about them strikes you and you want to meet them. For what reason? This desire, dictated by factors involving our 5 senses, it is nothing more than a search for sexual gratification. The evolutionary motivation of this behavior must be found in the need to reproduce, a need shared by all living beings. It is precisely our 5 senses that provide the brain with the necessary information to enter the first phase of falling in love.
Sex hormones
The hypothalamus plays an important role in this process, by receiving specific external stimuli (sight, hearing, etc.) it favors the production of sex hormones such as Testosterone y estrogens by the testicles and ovaries, respectively. One study has shown that testosterone increases libido in almost all men tested. The effects are less pronounced with estrogen, but some women in the study reported being more sexually motivated around the time of ovulation, when estrogen levels are highest.
Love enters through sight, whatever they say
Sight is usually the first sense that comes into play in the initial phase of falling in love. What we consider "beautiful" in our eyes it is generally dictated by the intrinsic beauty standards of the country where we grew up. In general, however, young, fit, shiny, thick, soft and healthy hair tends to be considered attractive. These are all indicators that they show reproductive fitness and therefore that the subject we are looking at could be a good candidate to mate and produce healthy offspring.
we fell in love by smell
Smell is the sense that is used once you get close to the other person. Not only are we attracted to the perfume that the other wears, but there are a series of volatile molecules called pheromones. The latter transmit a whole series of physical and genetic information from the "source" from which they come and activate physical and behavioral responses on the part of the "receiver".
A study conducted to demonstrate the effects of pheromones involved one group of women and one group of men. The women were forced to wear a shirt for three nights in a row and then the men were sniffed at. In men, an increase in testosterone production was found (and therefore libido) only after smelling the t-shirts of women who were ovulating at the time.
hearing, taste and touch
Hearing also "activates" desire. Men are attracted to high pitched voices while women are attracted to low pitched voices. Even touch and taste give their contribution in the search for the best candidate. Touching and kissing the other person allows our brain, from the first time, to evaluate the subject in front of us in a very short time and decide if it is a good match or not. The kiss, for example, is a rich and complex exchange of chemical and tactile cues that help the brain make decisions. It is precisely for this reason that many relationships are nipped in the bud after an unsatisfactory "first kiss."
We can say that it is our brain, helped by the 5 senses, the one that makes us "want" the best candidate!
Attraction
Once you get past the first stage and start a relationship with the other person, you enter the stage of attraction. Attraction involves brain pathways that control reward behavior.
When we talk about the reward system, we refer to a series of brain structures that are activated when they detect rewarding stimuli. For example, when we eat our favorite food, read a book we've been waiting for, or anything else we like, the brain releases a specific neurotransmitter: dopamine, which gives us a great deal of well-being. This is how the mechanism that drives us to search for that particular situation experienced is triggered. The purpose of this brain circuit is, therefore, ensure our motivation towards certain behaviors that the brain considers necessary.The reproduction and perpetuation of the species are, so they are driven by the reward system.
I get dopamine...
Spend time and have regular sex with your partner creates high levels of dopamine and a related hormone, norepinephrine, that are produced and released by the brain during this stage. Both strengthen the reward system and that is why the more we are together with the person we are in love with, the better we feel and the more we want to spend time with them.
The increase in norepinephrine usually produces insomnia and loss of appetite, greater attention and greater memory for new stimuli that characterize the first stages of human love. Norepinephrine is also associated with the peripheral sympathetic nervous system, causing increased heart rate, sweating, and tremor. Who has not lost their appetite or not slept because they were too busy thinking about their loved one?
we fall in love by attachment
Attachment is the stage where long-term relationships flow. While desire and attraction are pretty much exclusive to romantic relationships, attachment is the "sharing" phase with friendships, parent-child bonding, etc. The two main hormones in this phase are oxytocin y vasopressin.
Like dopamine, oxytocin is produced by the hypothalamus and released in large amounts. during sexual intercourse, lactation and childbirth. This may seem like a strange variety of activities (not all of them necessarily pleasurable), but the common factor is that all of these events are precursors to the bond to be forged.
In love relationships, as the bond is strengthened, oxytocin and vasopressin levels rise, transforming sexual desire into "tender love." In this phase, sexual attraction and desire are partially replaced by a less passionate affective bond, but stronger and more lasting. Oxytocin is often nicknamed from "cuddle hormone" for this very reason.
We can conclude by saying that the desire drives people to mate, attraction a preferring specific partners and attachment motivate people to stay together long enough to complete parenting tasks.
Conclusions
We like to think that love is something spontaneous that comes from the heart and that there is a hand of fate when we find the right person, but unfortunately, it is not so! Es our brain is the one that decides the fate of a possible relationship in a fraction of seconds and, if so, allows us to create a more or less lasting affective bond.