It’s so natural, we barely even notice we do it. Tilting a head to expose the neck, smiling or laughing at something that really wasn’t funny, moving closer to the person making unfunny jokes, mimicking their actions. Our body language is perhaps the most subtle expression of what we’re really thinking and feeling, and is a crucial component of the courting dance known as flirting.

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.