As humans evolved, researchers initially thought that those thick, protruding, caveman eyebrows served some key survival purpose, like providing support for chewing tough mammoth meat or intimidating competitors.

However, research shows that, more likely, eyebrows have evolved to serve a different purpose: expressing emotions in social situations.

Sure, eyebrows also keep sweat out of your eyes, but their most important purpose is in conveying your emotions. They’re the first place you can convey confidence. And that makes them the most important feature on your face.

Eyebrow trends are fairly cyclical. There’s not a lot of variation, when you think about it. The trend is either lots of eyebrow or very little eyebrow. I myself am a product of the late ’90s, when you couldn’t have eyebrows that were too thin.

But regardless of the trend (and whether you follow them), it’s important to have your eyebrows in order.

Whatever your preference, thick or thin, filled in or natural, your best bet for powerful eyebrows is to follow the Golden Ratio. Coined by Anastasia Soare, founder of Anastasia Beverly Hills, the Golden Ratio uses the mathematical principle of thirds to help you create the most flattering eyebrow shape for your face.

As with all professional make-up, you don’t want to over-do it. Keeping your eyebrows simple but groomed will help you put your most powerful face forward.