(CNN) -- Making a good first impression might have more to do with your facial features than choosing the right outfit, a new study reveals.
Researchers at the University of York in England analyzed people's first impressions of 16 social traits in 1,000 facial images. The traits were then organized into three categories: approachability, youthfulness/attractiveness and dominance.
The study reported that impressions of these traits can be formed in as little as 100 milliseconds from measurable characteristics such as the shape of and the spacing around your eyes, nose and mouth.
The facial features most associated with approachability were related to mouth shape: For example, those who were smiling appeared more approachable than someone who was frowning.
Attractiveness was linked strongly with eye characteristics; larger eyes, for example, were considered more youthful. And dominance was associated with eyebrow height, cheekbones and other stereotypical masculine features.
However, the researchers noted that all attributes had multiple cues, and no particular area of the face is essential to making these snap judgments.
"It is fascinating, and a bit worrying, to see how readily our first impressions of people are influenced by their appearance in photographs," explained Tom Hartley, one of the researchers, who is a neuroscientist and psychologist at the University of York.
He went on to write in an e-mail that different images of the same person could give different impressions based on pose or expression. Lighting and camera position can also play a role, which is important to recognize as people move to more online interactions where a profile picture might be the source of a first impression.
And that first impression can be easily be wrong, Hartley says.
So, he says, be wary of which pictures you're attaching to a resume, CV or online dating profile, as it could give off an unintended impression.
Based on data from the study, if you want to seem more approachable and youthful in appearance, select images with a front view instead of a side view. Smiles and head tilts are favorable. Eyes should appear as large as possible. And avoid facial stubble unless you prefer to appear dominant.
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