Sneakers have become a status symbol among Silicon Valley "techies." Many techies have never seen the insides of a black cap-toe Oxford shoe. The black cap Oxford gains more attention on the East Coast, where Wall Street investment bankers see it as a wardrobe staple. Many of these folks wouldn't be caught dead in sneakers. For them, even brown cap Oxfords constitute a fashion faux-pas. 

If you want to gain insight peoples' personalities, there are no shortage of options. We can look at their habits, their profile pictures, and even the way they walk. A study published in the Journal of Research found that our shoes also reveal a lot about our personalities. That is, we wear our hearts not on our sleeves but on our shoes.

1. Color

We've all encountered nonconformists who elect to stand out from the masses and wear colorful footwear. We often assume that people who wear colorful or bright shoes are extroverts. 

Aaron Levie, CEO of Box, is famous for sporting sneakers of the bright red or orange variety. He's also a classic extravert. Case in point: In response to one of former President Obama's State of the Union speeches that addressed solar power, robotics, and time travel, a confident Levie poked a little fun at the dignitary, remarking, "Essentially, he's reading a thank you letter to Elon Musk."

Another extrovert with an affinity for colorful shoes is YCombinator CEO Sam Altman. He was once asked to vacate a bar in London's Ritz Carlton Hotel on account of his ostentatious blue sneakers. Altman's extroversion has been the subject of much media attention of late. He's, for example, likened President Donald Trump to Hitler, writing in a blog, "Trump is irresponsible in the way dictators are... [his] casual racism, misogyny, and conspiracy theories are without precedent among major presidential nominees." 

We shouldn't be so quick to judge people who wear bright or colorful shoes. The study actually found that while we tend to believe colorful and bright shoes attract extroverts, there is no such relationship -- an introvert is just as likely to wear flamboyant shoes. 

It turns out that if you want to uncover extroverts, you should look at footwear wear and tear. The study found that extraverts are more likely to wear worn out shoes. They're also more likely to sport high-top shoes -- Chuck Taylors and the like. 

2. Condition

I work with a colleague who consistently blows me away with his attention to detail at work. He's also notorious for keeping his leather sneakers in impeccable condition. The boys at the SFO airport shoe shine service know him well. I would have thought these two predilections -- attention for detail at work and in attire -- would be closely related. It turns out this is not the case. According to the study, while we tend to assume that shoes in good repair indicate a more conscientious owner, there is no such relationship. 

This is not to say, however, that we can't glean anything about people from the condition of their shoes. The study found that people who wear well-kept shoes exhibit high levels of attachment anxiety. That is, they are more dependent on others and more apt to seek reassurance from coworkers about the quality of their work. Perhaps these individuals wear immaculate shoes in an attempt to make a good impression and avoid rejection? 

Admittedly, we all own a pair of ratty old gym shoes. While most of us wouldn't be caught dead wearing them to work, some mavericks don't give the matter a second thought. In addition to being more extroverted, the study found that those who wear worn shoes tend to be emotionally stable. They don't get bogged down by what others think about them. 

So, the next time you spot coworkers in worn shoes (think frayed laces, worn-out heel linings, and separated heals), don't be so quick to judge. They are likely emotionally stable and less likely to be the "clingy" type. 

3. Heel Height

Studies have shown that when a female wears high heels, she is deemed more attractive. High heels have long been considered a status symbol. The relationship dates back to ancient times. During Louis XVI's reign, high heels were worn by both males and females (even by Louis XVI himself) to denote status. 

Many critics have contested that women who wear high-heeled footwear tend to lack emotional stability. They are more likely to lack confidence and are clearly willing to put up with the pain of wearing heels (heels have been shown to increase mass muscle fatigue and strain). Does the instability and discomfort associated with wearing high heels reflect higher levels of emotional instability? 

According to the study, the answer is no. People who wear high heels are no more emotionally unstable than their counterparts. To this effect, it's not surprising to see confident leaders wearing heels. Sheryl Sandberg has posed for the cover of Time in a pair of stilettos. Marissa Meyer wore her signature high heels when profiled in Vogue. Women wear heels not because they lack confidence, but because this footwear choice makes them feel beautiful and powerful. 

Since ancient times, footwear has served a practical purpose in our lives -- in keeping our feet protected. Today, we know of a secondary contribution, that of gaining insight into personality types. Zappos marketers, the world is your oyster.