If you want to know your personality type, there is no shortage of choices out there. You could opt for the Myers-Briggs tests popular in the corporate world, or go with one of the countless Facebook and Buzzfeed quizzes that promise to reveal your true soul in the form of your spirit animal or Harry Potter analog.

But fun as they may be, none of these options is scientifically valid. In fact, up to now, psychologists generally insisted there was no such thing as personality "types." But a new study that examined no less than 1.5 million personality tests just changed all that. For the first time research has shown that, when it comes to personality, the majority of us really do fall into just four basic groups.

The quest to scientifically identify actual personality types.

Despite the popularity of personality quizzes, psychologists have long been skeptical of personality typing. We're all bundles of traits like extraversion and agreeableness, we all fall along a spectrum. Plus, our personalities change mightily over time. All of which means makes it difficult to nail down meaningful groupings.

"People have tried to classify personality types since Hippocrates's time, but previous scientific literature has found that to be nonsense," notes study co-author William Revelle.

But that was before the internet. Thanks to social media and the insatiable human thirst for distracting quizzes, these days it's perfectly possible to get 1.5 million people to take a research-validated personality test, generating a massive data set. And it turns out, if you crunch through enough data, you can succeed where so many others have failed.

When the researchers sifted through the data, they found some people are indeed personality unicorns -- strange and beautiful unto themselves and not much like any significant group of others -- but most of us cluster into just four distinct groups. That's not to say these groups describe everyone, the researchers caution, just types that are particularly common.  

Average, reserved, role model, or self-centered.

So don't get out the pitchforks if you don't feel you fall into one of these types. You may not. But chances are pretty darn good that you, or at least most of the people you know, do. What are they?

  1. Average: These people are high in neuroticism and extraversion, while low in openness. This is the most common personality type.

  2. Reserved: This type is emotionally stable but not open or neurotic. They are not particularly extraverted but are somewhat agreeable and conscientious.

  3. Role models: These folks score low in neuroticism and high in all the other traits. They are good leaders, dependable, and open to new ideas.

  4. Self-centered: This group scores very high in extraversion and below average in openness, agreeableness, and conscientiousness. In everyday life we call these people jerks.

While all four of these types are super common, they're not all equally distributed among the population. Women are more likely to be role models, for instance (the group best suited to leadership). Teenage boys, you'll not be surprised to hear, are overrepresented among the self-centered. Thankfully, they'll mostly grow out of it. The older you get, the more likely you are to fit into the role model group.

Who cares?

The biggest lesson here should probably be just how fluid and changeable your personality is. Science isn't saying you have one personality type that you're stuck with for life. In fact, the study captures just how much our personalities shift over time. So, if you wish you had a different personality type, you're fully capable of evolving.

That being said, the authors do think a scientifically validated personality type test like this may help business leaders make sure employees are well-suited to their jobs. The Department of Defense Army Research Office helped support the study, for instance, and it's not hard to guess why they might be interested in a research-backed measure of leadership potential.

But those practical applications are still a ways in the future. For now the main takeaway is just that a quest that's been ongoing since at least the time of the ancient Greeks seems finally to be over -- it appears there really are personality types. Now scientists just have to work out how to put that information to use.