9 Basic Elements in the Chemistry of Romantic Attraction

Thinking about what draws you to your romantic partner (now, or in the past), how easily could you put this into words? Try as you might, you can’t narrow it down to personality (similar to yours, or opposite?), appearance (blue eyes, brown eyes?), or even body shape and size (bigger or smaller than you?). You just know that, when in your partner’s presence, you feel that things are right with the world.

Psychologists who study close relationships aren’t necessarily that much better at coming up with a magic formula either. Most of the theories about attraction focus on those personality qualities of same or opposite, and less on the magnetic draw that leads people into each other’s lives (and arms).

In some ways, a greater understanding of romantic attraction may have little more than academic value. After all, attraction can throw you together, but it’s more likely to be conflict or other problems that drive wedges between people in a close relationship. On the other hand, as you can probably attest to from your own life, sometimes the “ineffable” (undefinable) qualities that can get you through the rough patches could be worth identifying.

Toward Defining Interpersonal Chemistry

According to York University’s Alexandra Liepmann and colleagues (2025), people in situations such as speed dating, at least as studied experimentally, may feel a “special or unique connection with a potential partner…which is not captured in a hypothetical list of desired traits.” Making matters worse from a research standpoint, the word “chemistry” is rarely and certainly not consistently defined.

There is something to go on, however, from University of Rochester psychologist Harry Reis and colleagues (2022), who developed the Interpersonal Chemistry Model (ICM), focusing on the two key factors of responsiveness (e.g., support and appreciation) and mutuality (compatibility of feelings and goals). Positive affect and attraction also fit into the ICM. However, the model isn’t specifically about romantic chemistry but instead about any relationship. Other researchers believe there’s something special about romantic chemistry, but they don’t know quite what it is. Even what is out there in the literature tends to be limited to the early connections that two people form, and not the kind of chemistry that characterizes successful long-term relationships.

To get to the core of romantic chemistry in established relationships, the Canadian research team decided that what’s needed is a “bottom-up” approach in which laypeople themselves provide their own definitions. Such an approach can shine a light on aspects of this concept overlooked in research while also gaining insight into how people use the term in their own lives.

Interpersonal Chemistry’s Nine Elements

Using a sample of 200 participants ranging from 21 to 76 (average age 41; 91 percent heterosexual), the authors posed the very simple question of asking participants to define romantic chemistry in their own words, using this prompt. See what you would say:

When people are deciding to pursue a romantic relationship or when they are judging the quality of an existing romantic relationship, they might consider whether they have ‘chemistry’ with the person. What does having romantic ‘chemistry’ with someone mean to you? How would you define it?

Next, the research team sat down to the task of organizing the 630 codes that the respondents generated into categories that emerged naturally from the data (as opposed to precoding according to set categories). Impressively, the coders came to agreement 93 percent of the time, which amounted to a corrected correspondence of 0.85 (accounting for chance). The resulting nine categories are as follows, with brief descriptions and examples; frequencies are indicated in parentheses:

Positive interaction (64%)

This, the most frequent category, included positive feelings, sense of connection or attraction, and enjoyment of time together: “You have an emotional connection with them.”

Mutuality (48%)

Feelings of mutuality included reciprocity and responsiveness: “Having chemistry means you both have a mutual interest in each other.”

Comfort (41%)

Feeling at ease and authentic; finding it easy to communicate; not feeling negative: “You are not afraid to share the innermost parts of yourself.”

Compatibility (40%)

Feelings of togetherness: “It means we match with each other really, really well…”

Similarity (36%)

Feeling alike to a partner: “They think alike, act alike, and share a lot of common interests.”

Unexplainable spark (31%)

Magical or unexplainable aspects: “It means the other person has the same vibrational energies as you do…”

Sexual attraction (28%)

Sexual/physical descriptors or attraction: “If a couple both have the same wants and desires when it comes to intimacy.”

Intense fixation (24%)

Feelings of intense focus with each other: “We want to be with each other all the time…”

Physiological response (6%)

Bodily sensations felt around partner: “…it feels like butterflies in your stomach…”

Did any of these elements surprise you in terms of being included or, perhaps, their frequency? You might wonder whether length of relationship and/or age might play a role in the findings. Indeed, people in longer relationships were more likely to mention romantic vs. sexual chemistry.

The nine elements also corresponded in part to the ICM, which the authors note, as “dyadic and transactional,” with six elements fitting into its themes. Expanding on this connection, the authors note that “one’s perceptions of goal-directed activity (i.e., repeated moments of connection) allow chemistry to develop between people.” This might remind you of the umpteen rom-coms of filmdom, in which the leading characters become drawn to each other while completing a joint task, often in the context of work. It’s probably no coincidence that people who share similar goals end up being in similar environments where they have the opportunity to express their values, personalities, and abilities.

What You Can Learn About Your Own Relationship

The study provides a road map for future research by offering a translation from laypeople’s conceptions of this universal concept into terms that could be investigated in further studies.

From your own perspective, it’s also useful to know that the spark with your long-term partner doesn’t have to fade over time. The authors were impressed with the durability of romantic chemistry, even if its focus shifts away from the sexual to the more emotional. As you try to think about why you’ve stayed with your partner (or what you’re seeking in a new one), these more durable features are the ones that will matter.

To sum up, finding a partner with whom you have chemistry seems to bring with it many potentially rewarding features. Comfort, ease, and those magical elements of being with that other person form an important part of the equation for long-term fulfillment.