Though cheesy pick-up lines abound, a lot is conveyed even before words are uttered. A prolonged gaze or arched eyebrow gives clues to the person across the bar that you’re interested without having to explicitly ask about his/her sign. Though the statistics differ, some attribute almost 80 percent of our first impressions to our stance and swagger. And because flirting helps both animals and humans find mates faster and easier, it is an evolutionary trait hard-wired in our brains. Mice twitch their noses at potential mates, colorful peacocks strut around for admiring peahens, and pigeons puff their chests to look buff. As much as we have moved on from mice and feathers, we do much of the same, for the exact same reasons.
Because flirting is an easy way for us to display our genes, mating potential, and interest, nature put a lot toward its success. This is one of the reasons why some males birds have exotic plumes, why elk carry hefty antlers (a sign of a healthy immune system), and why male fiddler crabs have such large claws. He waves his in the air, alerting females to his whereabouts, and signaling them to come closer for a better look at his burrow, colorful shell, and flashy claw.
Much in the same way, we’re physically programmed to indicate interest almost before we mentally have a say in it. Slight actions reveal a lot. Stance, eye movement, and gestures like leaning forward to talk to the person, or quick eyebrow raises are what scientists call contact engagement, signaling to the other mammal that you’re prepared for things to potentially get physical. Perhaps most importantly, these signals show that you’re not intending to dominate or flee. Or not just yet, anyhow.