You may have experienced some signs you’re in love. Can't get someone out of your head? Daydreaming about them when you should be working? Imagining your futures together? These dizzying thoughts are just a few of the telltale signs you're in love.
In fact, scientists have pinned down exactly what it means to "fall in love." Researchers have found that the brain of a person in love looks very different from one experiencing mere lust, and it's also unlike the brain of someone in a long-term, committed relationship. Studies led by Helen Fisher (opens in new tab), an anthropologist at Rutgers University and one of the leading experts on the biological basis of love, have revealed that the brain's "in love" phase is a unique and well-defined period of time. Here are 13 telltale signs you're in love.
Thinking this one's special
When you're in love, you begin to think your beloved is unique. The belief is coupled with an inability to feel romantic passion for anyone else. According to a 2017 article in the journal Archives of Sexual Behavior (opens in new tab), this monogamy results from elevated levels of central dopamine — a chemical involved in attention and focus — in your brain.
Focusing on the positive
People who are truly in love tend to focus on the positive qualities of their beloved, while overlooking his or her negative traits. According to the Journal of Personality and Social Psychology (opens in new tab), relationships are usually more successful when partners are idealized.
Those who are in love also focus on trivial events and objects that remind them of their loved one, daydreaming about these precious little moments and mementos. According to research published in 2013 in the journal Motivation and Emotion (opens in new tab), being in love prevents people from focusing on other information.
This focused attention is also thought to result from elevated levels of central dopamine, as well as a spike in central norepinephrine, a chemical associated with increased memory in the presence of new stimuli.
As is well known, falling in love often leads to emotional and physiological instability. You bounce between exhilaration, euphoria, increased energy, sleeplessness, loss of appetite, trembling, a racing heart and accelerated breathing, as well as anxiety, panic and feelings of despair when your relationship suffers even the smallest setback.
These mood swings parallel the behavior of drug addicts, according to a 2017 article in the journal Philosophy, Psychiatry and Psychology (opens in new tab). And indeed, when in-love people are shown pictures of their loved ones, it fires up the same regions of the brain that activate when a drug addict takes a hit. According to Fisher (opens in new tab), being in love is a form of addiction and when this is taken away from someone they can experience "withdrawals and relapse".
Going through some sort of adversity with another person tends to intensify romantic attraction, according to Fisher’s research. Central dopamine may be responsible for this reaction, too, because research shows that when a reward is delayed, dopamine-producing neurons in the mid-brain region become more productive.
People who are in love report that they spend, on average, more than 85 percent of their waking hours musing over their "love object," according to Fisher. Intrusive thinking, as this form of obsessive behavior is called, may result from decreased levels of central serotonin in the brain, a condition that has been associated with obsessive behavior previously. (Obsessive-compulsive disorder is treated with serotonin-reuptake inhibitors.)
According to a 2012 study published in the Journal of Psychophysiology (opens in new tab), men who are in love have lower serotonin levels than men who are not, while the opposite applies to women. The men and women who were in love were found to be thinking about their loved one for around 65 percent of the time they were awake.
People in love regularly exhibit signs of emotional dependency on their relationship, including possessiveness, jealousy, fear of rejection, and separation anxiety. For instance, Fisher and her colleagues looked at the brains of individuals viewing photos of a rejected loved one, or someone they were still in love with after being rejected by that person.
The functional magnetic resonance imaging (fMRI) showed activation in several brain areas, including forebrain areas like the cingulate gyrus that have been shown to play a role in cocaine cravings. "Activation of areas involved in cocaine addiction may help explain the obsessive behaviors associated with rejection in love," the researchers wrote in 2010 in the Journal of Neurophysiology (opens in new tab).
Planning a future
Longing for emotional union with a beloved, seeking out ways to get closer and day-dreaming about a future together are also signs of someone in love. According to an article by Harvard University (opens in new tab), when serotonin levels begin to return to normal levels, the hormone oxytocin increases in the body. This neurotransmitter is associated with creating more serious relationships.
Lucy Brown, a neuroscientist at the Albert Einstein College of Medicine in New York, says this drive to be with another person is sort of like our drive toward water and other things we need to survive.
"Functional MRI studies show that primitive neural systems underlying drive, reward recognition and euphoria are active in almost everyone when they look at the face of their beloved and think loving thoughts. This puts romantic love in the company of survival systems, like those that make us hungry or thirsty," Brown told Live Science.
"I think of romantic love as part of the human reproductive strategy. It helps us form pair-bonds, which help us survive. We were built to experience the magic of love and to be driven toward another"
Feelings of empathy
People who are in love generally feel a powerful sense of empathy toward their beloved, feeling the other person's pain as their own and being willing to sacrifice anything for the other person.
In Fisher’s study, the scientists discovered significant patterns in the brain activity of people who were in love. Their mirror neurons, which are linked to feelings of empathy, were more active in people who were in a long-term, loving relationship.
Falling in love can result in someone reordering their daily priorities to align with those of their beloved. While some people may attempt to be more like a loved one, another of Fisher's studies, presented in 2013 at the "Being Human" conference, found that people are attracted to their opposites, at least their "brain-chemical" opposites.
For instance, her research found that people with so-called testosterone-dominant personalities (highly analytical, competitive and emotionally contained) were often drawn to mates with personalities linked to high estrogen and oxytocin levels — these individuals tended to be "empathetic, nurturing, trusting and prosocial, and introspective, seeking meaning and identity," Fisher said in 2013 (opens in new tab).
Those who are deeply in love often experience sexual desire for their beloved, but there are strong emotional strings attached: The longing for sex is coupled with a desire for sexual exclusivity, and extreme jealousy when the partner is suspected of infidelity. According to the Indian Journal of Endocrinology and Metabolism, oxytocin is released during sexual activity. This hormone creates social bonds and develops trust.
This attachment is thought to have evolved so that an in-love person will compel his or her partner to spurn other suitors, thereby ensuring that the couple's courtship is not interrupted until conception has occurred. According to Fisher this evolved as a biological need, enabling people in romantic relationships to “focus [their] mating energy on a particular individual”.
Craving an emotional union
While the desire for sexual union is important to people in love, the craving for emotional union takes precedence. Fisher’s 2002 study published in Archives of Sexual Behavior found that 64 percent of people in love (the same percentage for both sexes) disagreed with the statement, "Sex is the most important part of my relationship with [my partner]."
Feeling out of control
Fisher and her colleagues found that individuals who report being "in love" commonly say their passion is involuntary and uncontrollable.
For her 1979 book "Love and Limerence," the late psychologist Dorothy Tennov asked 400 men and women in Connecticut to respond to 200 statements on romantic love. Many participants expressed feelings of helplessness, saying their obsession was irrational and involuntary.
According to Fisher, one participant, a business executive in his early 50s wrote this about an office crush, "I am advancing toward the thesis that this attraction for Emily is a kind of biological, instinct-like action that is not under voluntary or logical control. ... It directs me. I try desperately to argue with it, to limit its influence, to channel it (into sex, for example), to deny it, to enjoy it, and, yes, dammit, to make her respond! Even though I know that Emily and I have absolutely no chance of making a life together, the thought of her is an obsession," Fisher reported in 2016 online in Nautilus.
Losing the spark
Unfortunately, being in love doesn't always last forever and psychologists say that the early euphoric stage lasts no longer than three years, according to Fisher’s blog. It's an impermanent state that either evolves into a long-term, codependent relationship that psychologists call "attachment," or it dissipates, and the relationship dissolves. If there are physical or social barriers inhibiting partners from seeing one another regularly — for example, if the relationship is long-distance — then the "in love" phase generally lasts longer than it would otherwise.
To find out why people crave love and learn more about the research of Helen Fisher, you can watch her TED talk– The brain in love (opens in new tab). For further reading about love and the body, the book The Science of Love and Attraction (opens in new tab), written by neuroscientist Dr. Guloglu, explores how and why people love.
"Romantic love: An fMRI study of a neural mechanism for mate choice" The Journal of Comparative Neurology (2005). https://onlinelibrary.wiley.com/doi/abs/10.1002/cne.20772 (opens in new tab)
"Differences in Neural Response to Romantic Stimuli in Monogamous and Non-Monogamous Men". Archives of Sexual Behaviour (2017). https://link.springer.com/article/10.1007/s10508-017-1071-9 (opens in new tab)
"The benefits of positive illusions: Idealization and the construction of satisfaction in close relationships". Journal of Personality and Social Psychology (1996). https://psycnet.apa.org/record/1996-01707-007 (opens in new tab)
"Reduced cognitive control in passionate lovers". Leiden, Universiteit (2013). https://www.sciencedaily.com/releases/2013/11/131111091355.htm (opens in new tab)
"Addicted to love: What is love addiction and when should it be treated?". Philosophy, Psychiatry and Psychology (2017). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378292/ (opens in new tab)
"Reward, Addiction, and Emotion Regulation Systems Associated With Rejection in Love". Journal of Neurophysiology (2010). https://journals.physiology.org/doi/full/10.1152/jn.00784.2009 (opens in new tab)
"Defining the brain systems of lust, romantic attraction, and attachment. Archives of Sexual Behavior (2002). https://www.researchgate.net/publication/11151468 (opens in new tab)