Pahrump, Nevada, though a small town nestled in the desert roughly an hour from Las Vegas, draws a steady stream of visitors daily, primarily due to its two legally operating brothels.

My journey to Pahrump was driven by a scientific quest.

During a lunch at a conference a few months prior, my colleagues and I devised a plan to gather some initial observational data about the everyday experiences of brothel workers, as well as the behaviors and preferences of their clients.

We selected the brothel with the more favorable Yelp reviews for our inaugural field study, and soon after, I found myself heading west to meet with my fellow researchers in the heart of the desert.

As we arrived at the ranch, the sun was setting, casting a glow over the neon lights that illuminated this desert outpost.

The establishment resembled a repurposed single-story motel and featured two entrances: one leading to a restaurant and bar, and the other marked with the enticing sign: GIRLS! GIRLS! GIRLS!

We chose door number two, showed our IDs to a cheerful middle-aged woman in business-casual who introduced herself as the house manager, and filed into a long, high-ceilinged vestibule. Tile floors recently polished, air smelling of lilac and Lysol – it was dark, but inviting, in a luxurious way.

Justin R Garcia and his team of researchers chose the a brothel with good Yelp reviews to examine the operations of a legal brothel

The list of sex acts on offer was fairly straightforward, he said, except for the most expensive option: intimacy (File photo)

The manager rang a bell, summoning our guide who entered behind us, drawing our gaze to a large poster propped on an easel, which turned out to be a menu of sexual acts. 

Raquel was a former flight attendant turned sex worker with bright yellow hair and a Minnie Mouse voice. Married with two children, she began working at the brothel after losing her job during the economic crash of 2008. 

She was a gracious guide, affable in her understanding that we were on a scientific scouting mission of sorts.

My colleagues and I arrayed ourselves around the easel, and Raquel took us through the options. 

‘Our clients come from a huge range of backgrounds,’ she explained. ‘We get bachelor and bachelorette parties from Vegas, as well as guys and gals who have hit it big at the craps table and come on over to celebrate.’

The list of sex acts on the menu seemed fairly straightforward. I scanned the less expensive options, which included everything from sexual intercourse to shower parties to breast massages to drag dress-up, before my attention was drawn to the ‘special’ section of the menu – role-playing, lingerie, couples’ threesomes and more. That was when I spotted the most expensive item on the menu.

‘What’s the White Whale?’ I asked.

Starting at a base price of $20,000 (each worker set her own rates), it was clearly not an act for the faint of heart.

‘Oh, that’s the full Girlfriend Experience. A great choice for someone who wants something… personal,’ she said, adding, ‘A house favorite among high rollers.’

The option was dubbed ‘the full girlfriend experience’ – not unlike what Richard Gere’s character got with Julia Roberts’s character in the movie Pretty Woman

An employee told the researchers that clients of the brothel are often high rollers who have won big in Vegas

‘Sex isn’t necessarily a part of it,’ she told us. ‘But you’ll get a hell of a cuddle.’

We were struck silent by this revelation. Here was the most expensive sex act money could buy in a legal brothel, and it didn’t necessarily involve sex.

What people were buying was intimacy.

Intimacy is a broad term and a nebulous scientific concept. We use the word to describe a wide range of connections: the bond shared by a romantic couple, the unconditional love between parent and child, even the trust and support of close friends. 

But what do we really mean when we talk about intimacy?

In the abstract, intimacy is the pleasurable and comforting feeling associated with any close connection that grows between humans in a huge variety of contexts. 

In practice, it’s making eye contact across the table at a dinner party and knowing exactly what the other person is thinking; it’s feeling safe enough to lower your emotional armor and expose your deepest insecurities; it’s someone else sensing what you need, even before you know it yourself. 

In other words, it’s the experience of closeness, of feeling and being seen, and heard, and known.

Intimacy is at the core of every successful romantic relationship – whether it be between two people of different genders or two people of the same gender; whether among the young experiencing first love, or among seniors hoping to recast their closest connections; whether the relationship is monogamous, nonmonogamous or polyamorous.

There can also be intimacy in other types of relationships with friends, with family, even with coworkers. Intimacy is at the very core of the human condition, explaining so many of our best and worst behaviors.

Intimacy can also exist in other types of relationships: friends, family, even coworkers

Yet so few of us understand this essential drive – how it has impacted the evolution of our species, how it lives just under the surface of our desires or even how to harness it. We might not even recognize the need for intimacy as a biological drive, perhaps because it lives in the shadow of that other primal urge: our sex drive.

We tend to think of our ‘sex drive’ as the most powerful evolutionary motivator of modern relationships. For decades, evolutionary biologists have focused on what’s technically termed the ‘incentive motivational system,’ which assumes that our sex drive is an evolutionary adaptation designed to motivate the reproductive behaviors necessary for the species’ survival. 

But in focusing on sex and reproduction as the primary motive for romantic relationships, we have neglected a complementary core truth: that our motivation for intimacy and love is distinct from our sex drive. And it is also much stronger than we have been led to believe.

As my collaborator and friend the late Dr Helen Fisher would say, ‘Everywhere in the world people pine for love, live for love, kill for love and die for love.’

As an evolutionary biologist, sexologist and university professor, I have devoted most of my professional life to researching romantic and sexual relationships and the many variations of human sexual behavior and intimacy. 

The range of wants and needs I am fortunate enough to study is bountiful, beautiful and sometimes mind-boggling. This diversity in our intimate lives reveals something profound about the complexity of the human experience.

At the intersection of love and sex lies a fundamentally intractable evolutionary paradox: humans are wired to be socially monogamous – that is, we have a remarkable capacity and desire to form intense pair-bonds with other humans, usually one at a time, and sometimes lifelong – but we are not necessarily wired to be sexually monogamous.

What this means is that our sexual impulses are often in direct opposition to our existential need for love and intimacy.

My research, in the broadest sense, seeks to provide scientific context to what poets have pondered for centuries: our desire for sex coupled with our need for connection are powerful forces that underwrite so many of the peaks and valleys of our romantic and sexual relationships. 

Justin Garcia (left) is the executive director of the Kinsey Institute and serves as an advisor for dating apps Tinder and Hinge

Humans are wired to be socially monogamous, but we are not necessarily wired to be sexually monogamous, Garcia said

Our sexual impulses are often in direct opposition to our existential need for love and intimacy, Garcia said

These forces are baked into our deep evolutionary story as a highly social mammal and are intertwined with our biology, psychology and cultural systems.

When these two evolved drives – for sex and for intimacy – are in sync, we feel the kind of love and passion that poets dream of: all-consuming in its power and pleasure. 

The highs can be magically high. But the lows can also be painfully low. 

When our desires for intimacy and sex are at odds, we often find ourselves unhappy. We may pick a partner who satisfies us sexually but not emotionally – or vice versa – leaving us disappointed, heartbroken, unfulfilled. 

Many of the mistakes or bad choices that we make in relationships, both big and small – dating people who are wrong for us, drifting apart from a long-term partner, shattering the trust we share with another person – arise from this fundamental tension between our evolutionary desire for sex and our biological need for intimacy.

So, we’re left with a whale of a question: Can we reconcile our competing desires to enjoy a deeper and more satisfying form of romantic love?

I think we can. But it requires a new understanding of the evolutionary processes that continue to shape our romantic and sexual lives.

I’ve argued that humans have evolved with an intimacy instinct – that we seek out romantic love not just for reproduction and survival but also in the pursuit of self‐expansion. 

We are a variable and adaptive animal, and so we find ways to make intimacy work. But in the face of a loneliness epidemic and the increasing digitization of our social worlds, our ability to satisfy our drive for intimacy across our lifespan is being challenged more than ever. 

Failure to appreciate the science behind our choices is something we do at our own peril. Ultimately, if we fail to understand why we do what we do, we will be unable to achieve happiness and satisfaction with our relationships and our lives.

Exclusively excerpted from The Intimate Animal – The Science of Sex, Fidelity, and Why We Live and Die for Love by Justin R Garcia, published by Little Brown Spark, January 27