Humans are essentially animals. About 2 million years ago, the original Homo moved about the Earth in search of food, water and sex as well as protection from predators and environmental disasters in order to survive. One can picture the proverbial “caveman” with a wooden club, making utterances in some indecipherable language, roaming for necessities and warring for survival.

Of course, Homo exhibited traits outside of primal functioning, too — making fire, doing cave art, wearing “jewelry” and creating more complex tools. These abilities distinguished humans as sociable learners who used symbols to help explain their relation to others and their own existence.

But from this cognitive development, where did love evolve? Did the ability to love stem from our neurological complexity or from a selfish desire to survive through sexual reproduction?

To provide a framework for this question, we need to consider why we have sex. This isn’t such a straightforward answer — many organisms reproduce asexually. If we were to asexually reproduce, we’d pass on 100 percent of our genes. As every biology and anthropology student and one Richard Dawkins knows, propagating genes is an organism’s No. 1 goal in life.

So why do we only pass on 50 percent of our precious genetic material? Turns out, combining our genes with others creates more variability in the gene pool, thereby increasing an organism’s chances for survival. Much of this understanding rests on the “Red Queen Effect,” stating that sexually reproducing organisms constantly adapt to evade co-evolving microbes, parasites and environmental changes. This is why you have to get the flu shot each year — there’s always a new evolving strain that we have yet to develop immunity to. Still, explaining why and how we pass on genetic material doesn’t explain the passion, intimacy and longing we feel in romantic love.

What’s going on cognitively, emotionally and physiologically to induce love? Why do we reach the most extreme version of care, devotion and intimacy? And why does our world shatter when we lose it?

To begin, I must admit that love is complex; it initiates a swath of chemical reactions in several places of the brain. Nonetheless, there are regions that are activated more than others, particularly when it affects one’s motivation, attachment and holistic lifestyle.

According to anthropologist Helen Fisher, during intense periods of romantic love, activity in your ventral tegmental area and caudate nucleus illuminate. This part of your brain is associated with routine tasks (like muscle memory) but also one’s reward (or limbic) system. When romanticism exists, dopamine is triggered in this area, sparking prolonged desires, focused attention and exhilaration. But the caudate nucleus is associated with learning and memory, which means that this dopamine reaction permeates all aspects of life.

This idea is corroborated in David Brooks’ book, “The Social Animal.” In it, Brooks discusses psychologist Arthur Aron’s idea of love, unlike happiness or sadness, as a motivational state, leading to euphoria or misery. That is, depending on whether you’ve just had a first kiss or are mending a broken heart, your performance in a wide range of activities will be affected.

Additionally, that motivational state can often become an obsession. Psychologists like to call this feeling “limerence,” or the state of being involuntary infatuated with another person, hoping for a reciprocal response. Neurologically, this phenomenon also rests in one’s reward system. Cocaine is said to trigger the same responses as love.

But why do we maintain love with just one person? Fisher discusses three chemicals — serotonin, dopamine and norepinephrine — that become associated with one person in order to stir romantic passions. In comparison with lust, one’s sexual desire can be satiated from a broader inclusion of people. In short, loving one person creates an emotional pull unlike any other.

Furthermore, one personal connection becomes more salient in terms of attachment. An attachment is driven by hormones like oxytocin, which creates feelings of peace, serenity and calmness. After months of a relationship, two people become enmeshed with one another, thereby developing deep attachments.

Dr. Fisher states that after you “feel deep attachment to an individual … you feel intense energy, intense focus, intense motivation and the willingness to risk it all to win life’s greatest prize.”

Love induces addictive, withdrawal and relapse qualities. In other words, it’s a drug.

Of course, as many drugs do, love maintains terrible lows that often accompany its highs — like in a breakup. It would be easy if you could forget and remove the feelings once held for the person you loved, but you can’t erase your memories. The limbic system doesn’t forget. Instead, after being dumped, the reward system for wanting, craving, motivation and focus become more active when you can’t get what you want most.  

Personally, as someone who’s fallen in love, dumped someone and been dumped, I’ve experienced love’s euphoria and misery. And, like many others, I’ve found myself in each situation all at once.

Yet, for the emotional intensity that is a first date, breakup or intimate conversation, I believe we’re made better by our capacity to love. It’s deeply imbued with the passion that we personify as people, animating every aspect of our lives, whether we want it to or not. It also provides an incredible opportunity for learning. What better way to learn more about yourself, your partner or other people around you than through deep vulnerability and effusive intimacy?

Still, I can’t say for sure why love has evolved in humans. Maybe it’s helped us propagate our genes, deter war, share resources or just break the mundane routine. Regardless, it’s arguably one of the most distinguishing qualities of our species.

Sam Corey can be reached at samcorey@umich.edu.

 

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