The Science of Soulmates: 1920s Advice on the Chemistry of Love

In our digital age, we rely on algorithms to find love. We swipe right, we check compatibility percentages, and we filter by location, age, and interests with the tap of a finger. Dating apps promise to calculate our perfect match using data points and behavioral patterns. But in 1924, the search for a soulmate was viewed through a different scientific lens: Chemistry.

And I don’t just mean “sparks” or “butterflies.” I mean actual, literal chemistry—the kind you’d find in a laboratory.

When Science Met Romance: The 1920s Context

The 1920s were a peculiar moment in American history, caught between Victorian propriety and modern liberation. The decade that gave us flapper dresses, jazz music, and speakeasies also witnessed an explosion of popular psychology and pseudo-scientific approaches to everyday life. Following the horrors of World War I, Americans were hungry for certainty, for systems that could explain the unpredictable chaos of human nature.

This was the era when eugenics was considered cutting-edge science, when personality typing was all the rage, and when magazines promised to decode everything from character to compatibility through physical measurements and “scientific” analysis. Publications routinely featured articles that married genuine scientific advancement—like discoveries in chemistry and physics—with questionable applications to human behavior and relationships.

Women had just won the right to vote in 1920, and the “New Woman” was redefining femininity. Dating as we know it was becoming more common, replacing the formal courtship rituals of previous generations. Young people had more freedom to choose their partners, but with that freedom came anxiety: How do you know if you’re making the right choice?

Enter the experts with their test tubes and theories.

The Character Reading Series: A Window into 1920s Self-Help

The third article in our Character Reading series, titled “How Many Roads Can You Travel with Your Sweetheart?”, offers a fascinating (and somewhat brutal) take on compatibility. Published in 1924, this piece represents a broader cultural movement that attempted to systematize love, personality, and human connection through “scientific” principles.

The Character Reading series was typical of Jazz Age magazine content—a blend of genuine psychological insight, metaphorical science, and practical advice wrapped in authoritative-sounding language. These articles appeared alongside advertisements for miracle tonics, beauty products promising transformation, and correspondence courses that could supposedly turn anyone into an expert in weeks.

What makes this particular article remarkable is its argument that love isn’t a choice or a sentimental accident—it is a chemical reaction that can be tested, measured, and predicted. In an age when actual chemistry was revolutionizing industry and medicine, why shouldn’t it explain matters of the heart?

Love in a Test Tube: The Chemistry of Compatibility

The hook of this article is timeless: “Don’t blame him for not loving you! … Love has been caught and put in a test tube.”

This wasn’t merely poetic language. In the 1920s, chemistry was transforming the world. Synthetic materials were being created in laboratories, new medicines were being developed, and the periodic table was finally becoming understood. The average reader of 1924 would have been surrounded by advertisements for products “scientifically formulated” in labs, from household cleaners to cosmetics. The test tube represented modernity, progress, and truth.

The article cleverly harnesses this cultural fascination by using a vivid metaphor of “oil and water.” It argues that if you put two people in a “test tube” (a relationship or marriage) and shake them up with the “whirl of life”—financial pressures, family obligations, daily stresses—they might seem to mix for a moment. The initial excitement and novelty can create an illusion of unity. But if their chemical nature is fundamentally different, they will inevitably separate the moment things stand still and settle.

Think of those quiet Sunday mornings after the honeymoon phase ends, or the long silences during a cross-country drive. That’s when true compatibility reveals itself.

It is a comforting thought, isn’t it? It removes the blame. If it didn’t work out, it wasn’t because you weren’t enough, weren’t pretty enough, weren’t charming enough—it was just bad chemistry. Your essential natures were incompatible from the start. This perspective offered both absolution and explanation in an era when divorce was becoming more common but still carried significant social stigma.

The Triangle of Love: A Three-Dimensional Approach to Partnership

What elevates this piece above standard romantic advice columns of its era is its breakdown of the “Triangle of Love.” While other magazines might have obsessed over physical beauty or social status, this author takes a more holistic approach.

The piece warns against the “blind caresses” of purely physical attraction—a bold statement for a decade known for its sexual liberation and the breakdown of Victorian restraint. Instead, it proposes that a true “mate” (the preferred terminology of the time, which sounds almost clinical to our modern ears) must be able to travel three specific roads with you:

1. The Spiritual Road: Understanding each other’s ideals, ethics, and fundamental values. This wasn’t necessarily about organized religion (though that could be part of it) but about shared principles. In the 1920s, Americans were grappling with rapid social change—Prohibition, women’s suffrage, urbanization, immigration. Partners needed to be aligned on big questions: What kind of world did they want to build together? What principles would guide their family?

2. The Mental Road: Sympathy with each other’s studies, occupations, and intellectual pursuits. This is particularly progressive for 1924, when many still believed women should abandon intellectual pursuits upon marriage. The article suggests that true partnership requires mutual interest in each other’s work and thoughts. Can you have meaningful conversations? Do you respect each other’s minds? Will you grow intellectually together or drift into separate mental worlds?

3. The Physical Road: Where affection is the result of the first two, not the foundation. Here’s where the article gets truly interesting. Rather than dismissing physical attraction, it suggests it should be the natural outcome of spiritual and mental compatibility. The chemistry of physical desire, in this framework, is authentic and sustainable only when built upon deeper connection.

This three-part framework reflects the influence of emerging psychological theories of the time. Sigmund Freud’s ideas were spreading through American popular culture, though often simplified or misunderstood. The concept that humans had multiple dimensions—physical, emotional, intellectual—was becoming mainstream, replacing simpler Victorian notions of character.

Looking Five Years Ahead: Practical Wisdom for the Modern Era

It is surprisingly deep advice for a magazine that sits next to ads for “Pep Cocktails” and miracle weight-loss cures. The article asks readers to perform a thought experiment that remains relevant today: Look five years into the future. Imagine you’ve lost your youth, your novelty, your initial infatuation. What will remain?

“Will I want someone whose clothes alone I love, or will I want a companion who understands my mind and heart?“

This question would have resonated powerfully in 1924. The decade’s emphasis on youth and beauty was relentless—cosmetics companies were booming, fashion was changing at breakneck speed, and the “flapper” ideal celebrated a very specific (and temporary) type of youthful beauty. Yet beneath the glittering surface, people understood that beauty fades, fashion changes, and physical passion eventually mellows.

The article’s warning about mistaking physical passion for true understanding was particularly relevant in an era when dating was becoming more casual, automobiles provided unprecedented privacy for couples, and traditional chaperone systems were breaking down. Young people had more freedom than ever before, but less guidance on how to use it wisely.

The Revolution of Romance: How 1920s Dating Culture Transformed Courtship

To truly understand why a 1924 article would frame love as a chemical equation, we need to examine the seismic shift happening in American dating culture. The 1920s represented perhaps the most dramatic transformation in courtship practices since the Middle Ages.

From Parlor to Automobile: The Geography of Romance

Before World War I, courtship happened in the family parlor. A young man would “call” on a young woman at her home, under the watchful eye of parents or chaperones. The woman and her family controlled the space, the pace, and the propriety of the interaction. Courtship was a formal, stage-managed process with clear rules and expectations.

Then came the automobile.

By 1924, there were over 15 million cars on American roads—a staggering increase from just 8,000 in 1900. Suddenly, young couples could escape parental supervision entirely. They could drive to dance halls, speakeasies, movie theaters, and secluded “lovers’ lanes” beyond the reach of watchful eyes. The car became a “room on wheels,” a private space where physical intimacy could flourish without chaperones.

This geographic liberation created enormous anxiety among parents and moral guardians. How could young people be trusted to maintain virtue when they were literally driving away from supervision? Articles like “How Many Roads Can You Travel with Your Sweetheart?” emerged partly as a response to this anxiety—attempting to give young people internal guidelines when external controls were vanishing.

The Birth of “Dating” as a Concept

The very word “dating” was new to the 1920s. It had originated in working-class and immigrant communities in the 1890s, where young people without private parlors would make “dates” to meet in public spaces. Middle-class Americans initially viewed this practice with suspicion—it seemed dangerously impersonal and commercial.

But by the 1920s, “dating” had become the mainstream American courtship system. Unlike the old calling system where women invited men to their homes, dating flipped the script: men now asked women out and paid for entertainment. This shift had profound implications. Courtship moved from the private, female-controlled domestic sphere to the public, commercial, male-financed world of restaurants, theaters, and dance halls.

This created new questions and anxieties:

• How many dates before you knew someone was serious?
• Was it acceptable to date multiple people simultaneously?
• What physical intimacy was appropriate at what stage?
• How did you know if someone was truly compatible or just skilled at the performance of dating?

The 1924 article’s emphasis on looking beyond surface attraction and testing compatibility across multiple “roads” addressed these very modern concerns.

The “Petting Party” Panic and Sexual Liberation

The 1920s witnessed what contemporary observers called a “sexual revolution.” Surveys from the era (primitive by modern standards, but revealing nonetheless) showed that significantly more women born after 1900 engaged in premarital sex than those born in the Victorian era. The “flapper” became the symbol of this new sexual freedom—young women who wore short skirts, bobbed their hair, smoked cigarettes, drank bootleg liquor, and danced provocatively to jazz music.

“Petting parties” became a source of moral panic. These were gatherings where young people engaged in what we might now call “making out”—kissing and intimate touching that stopped short of intercourse. Judge Ben Lindsey of Denver, a progressive jurist who worked with young people, shocked the nation in the mid-1920s by revealing that such parties were commonplace among middle-class youth.

F. Scott Fitzgerald, the literary voice of the Jazz Age, wrote extensively about this new sexual culture. In his 1920 debut novel This Side of Paradise, he had a character declare that the modern girl was “given to ‘petting parties’” and was capable of choosing her own romantic destiny.

This is the context in which our 1924 article’s warning about “blind caresses” and purely physical attraction must be understood. The author wasn’t speaking to a sexually repressed Victorian audience, but to young people who had unprecedented freedom to explore physical attraction. The question wasn’t whether physical chemistry existed, but whether it was sufficient for lasting partnership.

Women’s New Roles and the Marriage Question

The 1920s woman faced options her mother never had. The 19th Amendment, ratified in 1920, gave women the vote. More women were attending college than ever before—by 1928, women earned 40% of all undergraduate degrees. They were entering the workforce in increasing numbers, particularly in new “pink collar” jobs like secretaries, telephone operators, and department store clerks.

Young women in 1924 had to make calculations their predecessors didn’t: Should I pursue education or husband-hunting? Can I have a career and marriage? What if my intellectual interests conflict with my husband’s expectations?

The article’s emphasis on the “Mental Road”—finding a partner who sympathizes with your studies and occupations—spoke directly to these anxieties. It acknowledged that women had intellectual lives worth considering in partner selection, a relatively progressive stance for the era.

At the same time, most advice still assumed women would ultimately prioritize marriage. The question wasn’t whether to marry, but whom to marry and how to choose wisely when old courtship guardrails had disappeared.

The Scientific Movements That Shaped 1920s Relationship Advice

The 1924 article’s scientific framing wasn’t arbitrary or merely metaphorical. It emerged from several legitimate scientific movements that were reshaping how Americans understood themselves and their relationships.

The Chemical Revolution: Science in a Test Tube

The early 20th century witnessed spectacular advances in chemistry that captured the public imagination. During World War I, chemistry had proved its power—both destructive (poison gas) and constructive (synthetic materials for wartime production). By the 1920s, chemical manufacturers were creating products that transformed daily life: synthetic fabrics, new dyes, plastics (Bakelite was the miracle material of the era), improved medications, and countless household products.

DuPont’s slogan “Better Things for Better Living…Through Chemistry” (introduced in 1935 but reflecting 1920s attitudes) captured the era’s faith that chemistry could solve any problem. If chemistry could create synthetic silk and cure diseases, why couldn’t it explain the mysteries of human attraction?

Popular science magazines of the 1920s regularly featured articles explaining chemistry to lay audiences. The test tube became an iconic symbol of scientific truth and modernity. When the 1924 article declared that “Love has been caught and put in a test tube,” it was invoking this cultural reverence for chemical analysis as the ultimate arbiter of truth.

The metaphor of “oil and water” that couldn’t mix was particularly apt because it was both scientifically accurate and easily observable. Anyone could see that oil and water separate—it was demonstrable, repeatable, and visual, all hallmarks of legitimate science. Applying this principle to human relationships gave romantic advice the veneer of scientific credibility.

Behaviorism: The Science of Prediction and Control

John B. Watson, the founder of behaviorism, was one of the most influential psychologists of the 1920s. His 1924 book Behaviorism became a bestseller by promising that human behavior could be understood, predicted, and controlled through scientific principles.

Watson’s famous (and wildly overconfident) claim captured the era’s optimism about scientific control: “Give me a dozen healthy infants… and I’ll guarantee to take any one at random and train him to become any type of specialist I might select.”

Behaviorism rejected introspection and focused entirely on observable, measurable behavior. This aligned perfectly with the 1920s cultural desire for certainty and control. If behavior could be predicted through scientific observation, then surely romantic compatibility could be assessed through objective criteria rather than unreliable feelings.

Watson himself brought this thinking directly into relationship advice. After leaving academia following a sex scandal (the irony was not lost on observers), he went into advertising and wrote extensively about marriage and child-rearing. His advice emphasized rational assessment over romantic emotion, habit formation over spontaneous feeling.

The 1924 article’s approach—breaking compatibility down into observable categories (spiritual, mental, physical) and warning against relying on emotional “blind caresses”—reflects this behaviorist influence.

Eugenics: The Dark Side of Scientific Mate Selection

We cannot discuss 1920s scientific approaches to love and marriage without addressing eugenics—the now-discredited belief that human populations could be “improved” through selective breeding. In the 1920s, eugenics was considered mainstream, respectable science, endorsed by presidents, taught at universities, and promoted by progressive reformers.

Eugenics didn’t just influence marriage advice—it was legally enforced. By 1924, 15 states had passed eugenics-based sterilization laws. The 1924 Immigration Act used eugenic principles to restrict immigration from Southern and Eastern Europe. Many states had laws prohibiting interracial marriage, justified through eugenic reasoning about “racial purity.”

Marriage advice of the era frequently contained eugenic undertones. Articles warned readers to consider not just their own compatibility, but their partner’s “stock”—their family history, heredity, and genetic fitness. Popular magazines ran features with titles like “How to Choose a Mate for Eugenic Marriage” and “The Science of Selecting Your Spouse.”

The emphasis on “chemical” compatibility in the 1924 article may seem benign compared to explicit eugenic advice, but it emerged from the same cultural moment that believed science could and should dictate human pairing. The article’s insistence that some people simply cannot mix—their natures are incompatible—reflects eugenic thinking about fixed, inherent characteristics that cannot be overcome through will or effort alone.

It’s worth noting that this represents one of the darker chapters in the history of “scientific” relationship advice. The same cultural forces that produced relatively harmless articles about the “chemistry” of love also produced laws that forcibly sterilized over 60,000 Americans and provided ideological justification for Nazi racial policies in the 1930s.

Psychoanalysis Enters Popular Culture

Sigmund Freud’s ideas, though developed in Vienna in the 1890s, exploded into American popular consciousness in the 1920s. Freud had visited America in 1909, but his theories didn’t achieve widespread cultural influence until after World War I.

By the mid-1920s, Freudian concepts were everywhere—often simplified, distorted, or misunderstood, but profoundly influential. Terms like “libido,” “complex,” “repression,” and “unconscious” entered everyday vocabulary. Popular magazines ran articles with titles like “Is Your Love Life Freudian?” and “What Your Dreams Reveal About Your Romance.”

Psychoanalysis contributed several key ideas to 1920s relationship thinking:

1. The existence of unconscious motivations: You might think you love someone for their charm, but unconscious factors (unresolved childhood issues, hidden desires) might be driving your attraction. This created anxiety: How can you trust your feelings if you don’t fully understand them?

2. The complexity of human sexuality and desire: Freud’s theories suggested that attraction was multilayered, involving physical desire, emotional need, and psychological patterns established in childhood. This aligned with the 1924 article’s insistence on multiple “roads” of connection.

3. The importance of psychological compatibility: Psychoanalysis suggested that neuroses, defense mechanisms, and unconscious patterns could create fundamental incompatibility between partners, regardless of conscious feelings. The “oil and water” metaphor captures this idea of deep, psychological incompatibility.

4. The dangers of repression: Freudian thinking warned against purely “spiritual” or overly restrained relationships that denied physical and emotional needs. This gave scientific legitimacy to the era’s sexual liberalization—physical attraction and expression were psychologically healthy, not shameful.

The 1924 article’s framework—acknowledging the importance of physical attraction while subordinating it to spiritual and mental compatibility—represents an attempt to integrate Freudian acknowledgment of sexuality with more traditional moral frameworks.

Intelligence Testing and Personality Typing

The 1920s witnessed the explosion of psychological testing. The U.S. Army had administered intelligence tests to millions of recruits during World War I, and after the war, testing mania spread throughout American society. Schools tested children, employers tested workers, and magazines offered readers tests to assess their personality, intelligence, and aptitude.

This fed directly into relationship advice. Articles and books promised to help readers assess potential partners’ intelligence, personality type, and character through observation and testing. The implicit promise was that with the right assessment tools, you could avoid romantic mistakes.

The Myers-Briggs Type Indicator wouldn’t be developed until the 1940s, but its intellectual precursors—attempts to categorize personality types and predict compatibility—were everywhere in the 1920s. Carl Jung’s Psychological Types was published in English translation in 1923, just a year before our article.

The 1924 article’s categorization of compatibility into three specific “roads” reflects this testing mentality. It suggests that you can objectively assess whether a potential partner meets criteria on each dimension, much like scoring a test.

Endocrinology: The “Gland” Craze

One of the more peculiar scientific fads of the 1920s was the obsession with endocrine glands and hormones. Scientists were just beginning to understand how glands like the thyroid, pituitary, and adrenal glands secreted hormones that influenced mood, energy, and behavior.

Popular culture seized on these discoveries with enthusiasm bordering on mania. Articles proclaimed that personality was determined by your glands. Are you shy? Thyroid problem. Aggressive? Overactive adrenal glands. Not in love? Your glands aren’t producing the right chemicals.

Some practitioners offered “gland treatments” promising to cure everything from depression to impotence. The more extreme claimed they could transplant animal glands into humans to restore youth and vitality. This was mostly quackery, but it was quackery with a veneer of scientific respectability.

The idea that love could be “caught and put in a test tube” reflects this glandular thinking. If emotions and personality were products of chemical secretions, then romantic attraction must be, too. Some researchers were even trying to identify a “love hormone” (they weren’t entirely wrong—oxytocin would eventually be identified, though not until the 1950s).

The Legacy: What the 1920s Can Teach Modern Daters

Looking back at 1924 from our vantage point in 2026, it’s easy to smile at the era’s naive faith in scientific solutions to romantic dilemmas. The specific scientific frameworks—behaviorism, eugenics, gland theories—have mostly been discredited or dramatically revised.

Yet the underlying impulse remains unchanged: We still desperately want systems, formulas, and scientific validation for our romantic choices. The test tube has been replaced by the algorithm, but we’re asking the same questions: Can science predict compatibility? Is there a formula for lasting love? How do I know if I’m making the right choice?

What’s remarkable about the 1924 article is that beneath its period-specific scientific language, it offers advice that modern relationship psychology largely supports:

• Multiple dimensions of compatibility matter: Contemporary research confirms that successful long-term relationships require alignment on values (spiritual road), intellectual compatibility (mental road), and physical attraction (physical road).
• Initial attraction is not sufficient: The “oil and water” metaphor, stripped of its chemical pretensions, accurately describes how relationships built solely on physical attraction often fail when faced with life’s pressures.
• Long-term thinking is essential: The advice to look five years ahead aligns with modern research on relationship satisfaction and mate selection.

The 1920s taught Americans to think scientifically about love—a mixed legacy that gave us both valuable insights and dangerous prejudices. Today’s dating apps and compatibility algorithms are the descendants of that 1924 test tube, still promising to reduce the magnificent chaos of human connection to measurable, predictable variables.

Perhaps the wisest takeaway from our 1924 article is not its specific scientific framework, but its insistence on depth, intentionality, and multiple forms of connection. Whether you call it chemistry, compatibility percentages, or traveling three roads together, the fundamental wisdom remains: Look beyond the surface, think long-term, and choose a partner who engages your full self—body, mind, and spirit.

In that sense, the advice from 1924 hasn’t aged a day.

Next in the Series: If you’ve found your “chemical affinity,” the next step is success. But in 1925, success wasn’t just about hard work—it was about being an “Oxygen Type.” In our next post, we’ll meet the “Go-Getter” of the Roaring Twenties.

Download the full 1925 Character Reading Digital Archive. Read the full magazine, view the illustrations, and discover the vintage secrets of personality.

Here is the full transcript of this 1924 article about dating and finding love:

Original Text: How Many Roads Can You Travel with Your Sweetheart?

(Transcribed from the December 1924 Issue of Character Reading)

Don’t blame him for loving you! Don’t blame him for not loving you! Love has been caught and put in a test tube .

If you have the courage to hold it up to the light, and look at it face to face, you will cease to pine because you do not bring forth the affection you are looking for from this one or that one. Love is a chemical thing—not a thing of will or creed .

No power on earth can make us love wholly if our physical, mental, and spiritual chemistry makes it impossible.

We think when we do not “get along together” that it is the voice, the habits, the clothes, the disposition, that cause our disagreements. But these things are only the results of our chemistry, and not the reason for our disagreements .

Look fearlessly into the test tube of love. If you take this step you will never hold a grudge against one you have loved and who does not return that love.

First, realize that you, in spite of your six feet, and breadth, are no different than the tiniest cell of your body and mind . You are you because that single smallest cell of you is what it is. That single cell contains every part of you in its chemistry . You are simply a billion and more of that one particular cell.

Suppose now, a single cell of you could be placed in the test tube. Now watch! Into this test tube we will place a single cell of the one you want to love you, but who does not .

The two cells tumble around and touch each other in some motions of the test tube, but not in others. They finally separate, for they have no “chemical affinity.” They remain, like oil and water, unable to attract each other or to become one .

If we whirl the test tube containing oil and water, they will seem to mix, but later the stillness again separates them. So also in the whirl of life and passion without spiritual love, two physical beings will seem knowingly become one for a short time, only to separate when the bigger part—the mind and spirit listening in the stillness—call for their own .

Natural law—not creeds—causes the sun to rise in the morning. Natural law only makes love possible, and natural law calls for love on three planes of expression—spiritual, mental, and physical .

Complete love has its “triangle.”.

For two cells, or two beings to become really one they must be able to answer each other in three different ways—or on three different roads.

First is the Spiritual Road—the road of true understanding of each other’s ideals, and ethics.

Second is the Mental Road—the road where our mental interests meet in our studies, our occupations, our ability to learn, our sympathy with each other’s mental interests, even if our talents are not equal.

Third is the Physical Road, where our caresses, our desire to be together are the result of our mental and our spiritual interests.

We cannot find the other two roads of each other by blindly caressing. Such love does not last when our physical interest comes first. When it comes, however, third, as a result of our mental interests, its joys are many times magnified .

We may love each other in two, or one of these ways only, and a very sweet, helpful and friendly marriage may be the result. We all want to find each other’s spirits and minds. We are all looking for that other part of ourselves which always exists somewhere in life, because everything in nature has its male and female principle in order to exist at all .

But too often we try to find each other’s spirit and minds, which alone can truly satisfy us, through the caresses of the body. The greatest of seers on love, Emanuel Swedenborg says that true love begins inwardly, in the spirit, and extends outwardly, “even unto the physical.” .

If we find our physical love for each other through our love of the spirit, we are nearer our true mate, and eternal happiness, than we are if we blindly try to find each other’s spirit through a physical demonstration only.

We will always have our mistakes in love unless we give our inner selves time to reflect—to search out our own personality—to send our souls ahead five years and to ask them “will I want in five years someone whose clothes alone I love, or will I want a companion who understands my mind and heart?”.

Next in the Series: If you’ve found your “chemical affinity,” the next step is success. But in 1925, success wasn’t just about hard work—it was about being an “Oxygen Type.” In our next post, we’ll meet the “Go-Getter” of the Roaring Twenties.

Download the full 1925 Character Reading Digital Archive. Read the full magazine, view the illustrations, and discover the vintage secrets of personality.