While love may be blind in some respects, your five senses actually play an important role in determining who you perceive to be a suitable partner—whether you realize it or not. Here are just some of the subtle ways sensory experiences play a role in your dating life:
1. THE EYES ARE THE WINDOWS TO THE SOUL.
A number of studies indicate that eye contact is vital to social encounters. One brain-scan study found that when people held sustained eye contact, they began to blink simultaneously, and after a while, their brain activity actually synced up. These long gazes can make people feel more attracted to one another. A set of 1989 studies found that after strangers stared into each other’s eyes for two full minutes, they reported an increase in feelings of passionate love.
Eye contact also signals that the person could reciprocate your affections. Another study found that people are more attracted to faces that are looking directly at them and (crucially) smiling. “Collectively, our ﬁndings indicate that attraction is inﬂuenced not only by physical beauty, but also by the extent to which a person appears open to engaging the observer,” the researchers wrote in 2006.
Though most research on the science of romance tends to focus on heterosexual pairs, studies have found that LGBT people also reveal some subconscious sexual feelings with their eyes. A 2012 study found that men’s pupils dilated in response to images they found sexy. Straight men’s eyes dilated in response to a sexy video of a woman, gay men’s eyes dilated in response to a sexy video of a man, and bisexual men’s eyes dilated in response to both. (But to make things more complicated, straight women’s eyes dilated in response to videos of both men and women, despite their reported feelings of arousal.)
2. THE NOSE KNOWS BEST.
Smell plays an important role in attraction, though it may not always be obvious. Though the research isn’t entirely clear-cut, there’s evidence to suggest that people subconsciously use smell to ferret out appropriate mates.
Famously, researchers have tested volunteers’ attraction to the scents of potential partners by having them smell dirty t-shirts that have been worn by someone of the opposite sex. Several versions of this type of study [PDF] have found that women tend to prefer the smell of sweat from men whose immune systems genetically differ from their own. In theory, this would be evolutionarily beneficial, because it would prevent mating between relatives and increase the chances that their children would have strong immune systems.
Other studies have linked pheromones to sexual orientation and gender perception. One found that gay men’s brains react to testosterone from male sweat as a sexual pheromone, while they smelled estrogen derived from women’s urine as a normal odor. Another study, in 2014, found that when people attracted to men (straight women and gay men) smelled cloves laced with a testosterone derivative, they perceived the gender presentation of a simulated person walking toward them as masculine. In turn, when straight men smelled an estrogen derivative, they perceived the person’s gender presentation as feminine.
3. TOUCH IS HEALTHY, AND PERSUASIVE.
Romantic touch isn't the same as other tactile sensations. According to one brain-scanning study, when people think about touching a romantic partner, it activates a different part of the brain than thinking about touching an inanimate object would. The researchers found that this brain activity correlated with the degree of passionate love the partners reported on a survey.
And in the right context, a light touch can be quite persuasive. A 2007 study found that when a man touched a woman’s arm lightly while asking her to dance, she was more likely to say yes. Other research has found that touch increases the brain’s response to an emotional situation. “Such enhanced processing may then, among others, boost empathy and increase the likelihood that the touch recipient acts in favor of the toucher,” the researchers wrote in 2011.
In the context of love, though, touch can be more than just pleasurable. Touching a romantic partner may help protect you against stressors. Some research has found associations between hugging a long-term lover and lower blood pressure [PDF]. In one 2003 study, people who held hands and hugged their live-in partner before a stressful event (public speaking) exhibited fewer physiological signs of stress, including lower blood pressure and heart rate, compared to people who rested quietly before the public speaking task. A 2007 study specifically looking at women’s stress responses found the same result.
4. YOUR VOICE CAN REVEAL YOUR ATTRACTIVENESS.
A 2004 study found that your voice may carry some information about your sex life. Researchers asked volunteers to listen to anonymous recorded voices and rate their attractiveness, then compared those ratings to survey information about the speakers. They found that, among other things, people with attractive voices tended to have more sexual partners than people with unattractive voices. So maybe the attractiveness of your voice does indeed correlate with whether you’ve got game.
Another study from 2014 found that people change their voices when speaking to someone they find attractive. The study looked at people speaking both English and Czech. Men’s voices varied more in pitch and went lower when they were speaking to a woman they were attracted to than someone they weren’t attracted to.
5. LOVE IS SWEET.
Kissing isn’t an entirely universal human activity, but it is a popular one. While its exact purpose isn’t clear, some researchers suggest that it might be about taste-testing “gustatory cues found in skin oils and saliva compounds,” as one study puts it.
You actually share a lot of information about your immune system when you swap spit. In 2014, Dutch researchers brought 21 couples into the lab and had them make out. They took saliva samples from everyone before and after they kissed to test how oral bacteria might play a role in attraction and love, and in between kisses, they gave one partner a probiotic yogurt drink to test how much bacteria is swapped when people make out. They estimated that as much as 80 million bacteria are swapped between a couple in 10 seconds of kissing. They also found that couples had oral microbiomes that were more similar to one another's than the microbiota of unrelated people, and the more they kissed, the more similar their bacterial colonies were.
And if your partner's spit tastes sweet to you, you might just like them more. It seems that sweet tastes prime you for love—one study found that people who ate sweets in the lab were more likely to express interest in a hypothetical relationship [PDF].