Appearances might be deceiving but they can also be revealing.
According to one new study we can accurately judge another's attractiveness in just 13 milliseconds. That is faster than the 100 milliseconds researchers previously thought we took and much faster than the blink of an eye (which takes 300 to 400 milliseconds).
More new research by neuroscientists at York University confirms that first impressions count.
In the first rapid fire moment of assessment, researchers found that we process facial features, attributing them to traits like dominance, submissiveness, trustworthiness, intelligence and approachability.
To determine the accuracy of these deductions, the researchers created mathematical models of different faces capturing the physical traits associated with those characteristics.
They then showed participants in the study the faces to confirm that the impressions and physical traits matched up.
"First impressions of social traits, such as trustworthiness or dominance, are reliably perceived in faces, and despite their questionable validity they can have considerable real-world consequences," the authors said.
Lead author Tom Hartley warned that in the real world different features often combine on one face meaning such deductions aren't so simple. Still, they found someone with a broad smile is seen as more trustworthy and approachable while someone with a good tan and strong jawline is considered to be more dominant.
Separate studies published this year have further explored our impressions as well as the link between facial and character traits.
One found that while there is no correlation between face shape and intelligence, we have the impression that there is.
Faces that are perceived as highly intelligent are longer with a broader distance between the eyes, a larger nose, a slight upturn to the corners of the mouth, and a more pointy chin.
Another new study found that while not necessarily smarter, moon-faced men are more financially savvy than thin-faced fellows.
The study, by University of California-Riverside, London Business School, and Columbia University, found strong-headed men were more tenacious negotiators.
In scenarios set up by the researchers they haggled for higher bonuses, getting nearly $2200 more than men with a more narrow face. They also managed to negotiate higher prices when selling fictional properties.
That said, researchers found that fat-faced men tended to behave more selfishly and were more likely to lie and cheat while men considered to be more attractive were better collaborators.
The study did not examine whether the same was true for women, but facial structure it seems can predict certain characteristics, the authors said.
A separate study by Cornell University researchers explored the real-world consequences of judging a book by its cover.
Participants were shown a photo of a stranger and asked for their instant impression.
The strangers were then introduced more than a month later and, it was found, the participant's initial instinct was surprisingly accurate.
Others warn that going on first impressions is something best kept for face-to-face interactions. This is because the context of environment can help us make more rounded evaluations.
Yet the evidence that instinct can be impressively accurate stacks up.
"Despite the well-known idiom to 'not judge a book by its cover', the present research shows that such judgments about the cover are good proxies for judgments about the book – even after reading it," said the Cornell study author Vivian Zayas in a statement.
This is significant given that these days our first impressions of others are often online.
The findings from such studies may lead to computer programs that pick which pictures will help us put our best face forward.
"You would be able to use these kind of [findings] to decide when is a good time to take a photograph, or maybe to choose the photograph that's really optimal in putting forward the best possible impression," Tom Hartley said, "and you might want to put forward different kinds of social impressions in different situations."