Psychologists from universities of Glasgow, Scotland, and Princeton, U.S. have found that an individual determines the trustworthiness of another person within the first 500 milliseconds of hearing their voice. Researchers said that a simple 'Hello' is enough to judge a personality type.

The interesting part of the finding is that these conclusions are made sans visual cues.

For the study, the researchers asked participants to listen to recordings of several people and rank them based on 10 personality traits including trustworthiness, dominance, attractiveness and warmth. The researchers found that within 300-500 msecs of hearing the recordings, the participants formed opinions.

Trustworthy and dominance traits were the major traits identified. Males who raised their tone and women who altered the pitch of their voices were deemed trustworthy. Dominance was characterized when voices lowered their pitch in the recordings.

The findings suggest that humans have the ability to assess first impression quickly by just listening to the tone of others saying 'Hello.' The researchers believe that this ability might have evolved in recent history when 'trusting others' became crucial to mankind's survival.

"It is amazing that from such short bursts of speech you can get such a definite impression of a person. And more so that, irrespective of whether it is accurate, your impression is the same as what the other listeners get, Dr Phil McAleer, from the Voice Neurocognition Laboratory, University of Glasgow and principal author said in a statement.

"It is perhaps also consistent that we are most attuned to recognizing signs of trustworthiness and dominance, two traits that would have been central to our survival as we evolved."

The study helps enhance the efficiency of voice-operated systems and learning aids. It also gives a different perspective on automatic judgments we tend to make about strangers we don't meet in person.

However, when you do meet someone in person, here is how you can make a good impression, according to Business Insider:

- Pay attention to your hair, makeup and finger nails. Finger nails needs to be clean and must be either trimmed or manicured. Makeup should be done to enhance one's features not to draw attention.

"If you're going to show your toes, make sure your toes are well-groomed," Nicole Williams, a career expert at LinkedIn told Business Insider.

- For men, their facial hair needs to be maintained trim and tidy to obtain a professional look.