I’ve always been very skeptical. I’ve never believed in horoscopes. One night, while brainstorming the app, one of our team members asked, “What kind of person believes in astrology?” We were about to find out.

The first thing we learned was that the horoscopes themselves were … sketchy. It turns out most horoscopes are repeated within a matter of weeks. Why don’t people see this? Because they’re repeated across different signs. Leo will feel a bit down today and then, surprise, it will be Scorpio’s turn to feel blue in two weeks. But since Scorpio doesn’t read Leo’s horoscope, no one will ever notice.

Obviously, this is a ploy to extract as much juice as possible from a few lines of pure magical spells.

Because that’s what horoscopes are: spells. But these aren’t Hermione Granger, full-marks-to-Gryffindor types of spells. Rather, these are the kinds of spells that Tony Robbins or Trump can weave to cajole half a country into believing what they believe. Brain hacks. Word prestidigitation. Manipulation wizardry.

How Horoscopes Manipulate You

I know you, dear reader. I know how you think. I know who you are.

You have a need for other people to like and admire you.

You have a tendency to be critical of yourself.

You have a great deal of unused capacity, which you have not quite turned to your advantage.

At times you have serious doubts as to whether you’ve made the right decision or done the right thing.

You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations.

You pride yourself on being an independent thinker and do not accept others’ statements without satisfactory proof.

You have found it unwise to be too frank in revealing yourself to others.

If you saw any of those statements as the result of a personality test, you would rate their accuracy as 9 out of 10. This phenomenon has been tested and labeled as the Forer (or Barnum) effect: Take a very common human thought, make it vague, tell people it is tailored to them, and they will almost always believe you’re talking about them. Why?

If I tell you, “You’re courageous,” your mind immediately goes to a time when you were courageous. So you’ll think, “Yeah, that’s right, I did this courageous thing one day. I’m courageous!”

If then I add “…but sometimes, you don’t dare to do things,” you’ll think “Yeah! That’s true too! I remember a time when I didn’t dare to do what I really wanted to!”

You’ve just told a person they are one thing and its complete opposite, and they think you’re a genius. Because we’re all complex animals, both statements can be true about you at some point. You’re not thinking in overall averages. You’re recalling the specific events that prove my statement.

The same principles are used in persuasion, hypnosis, and many other disciplines that try to hack brains.

And it’s also true of horoscopes. Except that on top of that, they’re mostly about the unknowable future, not just the knowable past. Nobody’s going back to fact-check whether everything turned out right.

Let’s take a random horoscope:

“You probably aren’t going to feel very social today, Sagittarius. In fact, you’re likely to want to work on projects and tasks alone if you can. This might be good for you, since you probably need to concentrate without being distracted. Still, you should get out among others at some point during the day. You might want to be alone, but you’ll still need to feel that you belong.”

Who in the world has not felt like that? Some of us feel that way nearly every day! More precisely, who has not read something like that and said, “Oh yeah, that sounds like it could be me today.”

How unbelievably accurate.

But there’s more! See what they did? They told you you should be alone and you should be social in the same breath! But it doesn’t feel weird. Our brains are so easy to hack….

So that’s how horoscopes work.

Do people believe in them?

Yes. And no.

Let me explain.

Do People Truly Believe in Horoscopes?

Around 25% of people say they believe in horoscopes. That’s a lot. On the opposite side, around 25% of people say they don’t believe. That adds up to 50%. What’s up with the other 50%?

They “enjoy” them.

What does that even mean?

The 25% that believes truly believes: They make sure they get their preferred horoscope. They plan tomorrow according to today’s horoscope. Sometimes these people plan out years in advance on astrological conjecture. They choose their partners based on their signs. They aren’t messing around when it comes to finding the truth in the stars.

The 25% that doesn’t believe truly doesn’t believe. They will go out of their way to tell you how dumb horoscopes are, any chance they get.

The 50% in between runs the gamut from believers to nonbelievers. Many will tell you, for example, that they don’t think horoscopes are factually correct, but they can be personally right or relevant. Some might tell you that they don’t really believe in them, but they’re fun to read. For all the people out there who can’t make it to a haunted house to hunt ghosts or to the Pacific Northwest to track Bigfoot, horoscopes give them an entertaining way to grasp the enormity of how little we actually know for sure in this universe.

So what does this all mean? It means that nearly 75% of people are interested in their horoscopes, in some way or another. Great for our app! But as the numbers were going up and up and up every day, we weren’t prepared for how some people would treat them as gospel.

How We Opened Our Eyes

One moment stands out. On an otherwise uneventful day, I was slouching on my chair, in front of my laptop, reading down the list of messages from our readers, when I stumbled upon something like this:

“Hello. I’m a 36-year-old who is divorced. I have a 21-year-old boyfriend. We’ve been going out for 2 months. He’s my last opportunity. Will I marry him, or will I be alone for the rest of my life? Please help me you’re my only chance. Ciara.”

I stopped what I was doing. The despair hit me.

It’s one thing to be scared about your future loneliness.

It’s something completely different to trust the answers to a horoscope.

It’s another level of despair altogether when you ask for advice on what might be the most important question of your life in the customer service section of a horoscope app on Facebook.

This is when it hit me: Horoscopes are not true. But they’re real. And impactful. Because so many people believe in them, and modify their lives accordingly. I stopped working on my horoscope app that day.

Horoscopes are not true. But they’re real.

Well, that was bleak. Is there a takeaway that might raise my spirits?

Soon after, I would leave that company. As I wrapped up my work, I reflected on the main lessons I learned from it.

First, if you’re looking to create a viral product, take newspapers as a source of inspiration. Years of experimentation have taught them exactly what people are interested in — including horoscopes, but also weather, sports, politics….

Another key insight was how easy it is to manipulate us. Those who craft horoscopes know, consciously or unconsciously, how to do it. They do this by using generic statements that fit nearly every human being. But they aren’t the only ones. There’s a science to influence, and thousands of people make it their life mission to learn that science.

That means we all have a responsibility to call out pseudoscience.

The more we teach people to simply accept anecdotal stories, hearsay, cherry-picked data (picking out what supports your claims but ignoring what doesn’t), and, frankly, out-and-out lies, the harder it gets for people to think clearly. If you cannot think clearly, you cannot function as a human being.—Phil Plait

What starts with laughing at a horoscope can evolve into bad decisions, including influencing life-changing ones such as who to marry.

And if Facebook — or some equivalent company — comes knocking on your door for a job, think carefully what your efforts are fueling. The world we live in, full of fake news, conspiracy theories, Russian interference in elections, Cambridge Analytica, usage of Facebook to spread….

All of that sounds recent, but this was there all along.

It was there when Facebook was created in 2006.

It was there when I was working on its apps in 2011.

It was there when Cambridge Analytica started using it in 2015.

With great power comes great responsibility. Whenever you’re creating something that’s massive, that many people use, no matter the industry, you’re impacting human lives. You have a responsibility to use your power for good. Make sure to consider your responsibility to the people using your product, and then you can confidently push your business forward.

And I would know a thing or two about confidence. After all, I’m a Sagittarius.