First dates can be equally as exciting as they are awkward, so what's really the key to a good first date—and getting a second one? That's what researchers wanted to figure out in a new study published in the scientific journal Nature.

As it turns out, there are some very subtle body language cues you can look for to know if things are going well.

For this research, the team observed physiological and behavioral factors during first date encounters of 46 heterosexual pairs. The study involved rounds of speed dating, in which each date lasted five minutes. During those five minutes, the participants' physiological responses were recorded by a wristband, as well as their body language and movements, such as nodding or shifting positions.

Following the dates, the participants recorded how interested they were (romantically and sexually) in their dates.

Based on the findings, it would appear what makes a great first date is how well both people can "synchronize" and "attune" to the other. The pairs who were more synchronized and attuned to each other were more likely to report attraction to the other.

"Synchrony is defined as the matching of affective states and biological rhythms in time for the purpose of social regulation," the researchers write. "While synchrony refers to the simultaneous matching between partners, attunement refers to the sequential adjustment of behavior in response to the partner."

Mirroring each other's body language is a good example of attuning behaviorally, and the researchers found pairs who were most attracted to each other even experienced their nervous systems seeming to harmonize with one another. They measured this via each person's electrodermal activity (electrical characteristics of their skin), which they note "reflects the level of arousal and orientation of attention."

Women were actually more impacted by degrees of synchronization, being more attracted to men who displayed high levels synchrony. (Men found it desirable too, just women more so).

As the study authors write, "When a man and a woman are highly synchronous and attuned during a date, their mutual romantic and sexual interest are high as well. This provides evidence that sexual and romantic attraction in humans involve social adjustment of the sympathetic nervous system and motor behaviors."

It's worth noting that these findings were only based on heterosexual couples. And further, it's unclear whether attunement results in attraction, or if attraction boosts attunement.

Either way though, psychologist and study co-author Shir Atzil, Ph.D., says the results indicate that body language is a powerful sign of attraction, if not a catalyst for it. "Connecting with a partner depends on how well we can synchronize our bodies," she says in a news release. "Our research demonstrates that behavioral and physiological synchrony can be a useful mechanism to attract a romantic partner."

So, what does that mean for you, practically speaking?

If you've got a first date coming up, pay attention to your date's body language, and whether you feel you're both "vibing" on the same level. If your date displays engaged body language and you feel a certain resonance in your energies—congrats. You just might have a second date to look forward to.