People can form first impressions in less than a second by just hearing how you say hello, says a new study.
For the purpose of the study, University of Glasgow's Phil McAleer, along with his team, recorded over 60 people while they said hello, New Scientist reported.
Then the opening word's of 64 people were repeated in front of 320 people, who were asked to rate the voices on a scale of 1 to 9 for one of 10 perceived personality traits.
Although it is not known what people base their judgements of some stranger's voice on, the study found that all the participants made them and fast.
There's this evolutionary 'approach/avoidance' idea where you want to quickly know if you can trust a person so you can approach them or run away and that would be redundant if it took too long to figure it out, McAleer said.
The findings also showed that a guy who raises his pitch becomes more trustworthy, whereas a girl who glides from a high to a low pitch is seen as more trustworthy than a girl whose voice goes up at the end of the word.
The study is published in journal PLoS One.