Smiling is not the only indicator of availability. Behavioral investigator Vanessa Van Edwards revealed to Science of People that uncrossing your arms is yet another way you can signal your availability to a potential partner.

Chris Ulrich, senior instructor at the Body Language Institute, agrees. "Crossed arms can make you seem closed off or disinterested," the expert revealed in an interview with Glamour. "You're subconsciously creating a barrier that makes you not as approachable as you want to be." 

That's not to say you should always keep your arms uncrossed. "Science says you're more likely to work through a difficult problem with your arms crossed," the expert admitted. And, let's be honest, sometimes you're just cold or don't know what to do with your hands other than tuck them into your arms. Nevertheless, when it comes to attracting a mate, uncrossed appears to be the way to go.