We've all heard that first impressions are incredibly hard to shake. Experts often say that's because of cognitive biases that make it hard for people to change their opinions once they've formed them. But new science suggests another possible cause for the durability of these initial opinions -- we might hold onto them so tightly because often they're uncannily correct.

Psychological research blog PsyBlog recently rounded up some of the most eye-catching new findings on personality, and among the not-entirely shocking results showing we get nicer as we age (anyone who's ever been to middle school could tell you that) and we live longer if we're optimistic were a trio of studies that suggest humans have a strange and pretty powerful ability to suss out strangers' personalities from the tiniest of clues.

You smell very neurotic today?

The first, and perhaps the oddest, of the studies found that simply by smelling a person's T-shirt, participants could guess some key personality traits of the wearer, such as neuroticism, extraversion, and dominance.

"The study showed that people were as accurate at guessing personality when smelling [strangers'] clothes as when watching a video of them," reports PsyBlog.

I like the way you move

If you can't catch a whiff of a new contact to get a sense of his or her personality, you could also try simply watching how the person walks across the room. Another new finding out of the U.K. suggests that people are also weirdly good at assessing people's personality -- and whether they want to get to know them -- from their gait.

"This study shows that people who move in a certain way will also react in similar ways when they are performing joint tasks," said study author Krasimira Tsaneva-Atanasova. "Essentially, our movements give an insight into our inherent personality traits. What we demonstrate is that people typically want to react and interact with people who are similar to themselves."

What your wide-spaced eyes are saying to the world

Even if you are sitting in a chair and well dosed in deodorant, you might be giving away details of your personality. New science also shows that "people read a surprising amount into our faces, just from one glance," PsyBlog reports.

The specific study highlighted in the post looked at romantic situations and what people inferred about strangers' dating preferences from nothing more substantive than the shape of their faces. "Men who have large noses, square jaws, and small eyes are apparently telling the world they prefer short-term relationships," the research concluded. "Women with larger lips and wide eyes are sending the same short-term relationship signal -- whether they like it or not."

That's annoying news to monogamy-preferring wide-eyed girls, but apparently this line of research goes beyond helping would-be lovers better target their advances. (In fact, the researchers sensibly caution against using these signals out in the real world. Assuming too much on the basis of someone's looks is not only rude but also a recipe for dating disaster.)

Other science shows that, like it or not, facial features can reveal more than we would sometimes perhaps like about our personalities. "Lots of previous studies have shown that people can judge a lot about a person from their face, including things like health and even some personality traits like introversion," noted study author Ben Jones.

Taken together, these three studies, as well as the related research they build on, suggest that first impressions aren't just lasting because people are loath to change their minds. If you can gather so much information from a whiff, the set of someone's eyes, or a quick stroll across a room, no wonder people are so strongly attached to their initial assessments.