New research has found that friendly or outgoing people score higher on attractiveness.
In the study, Gettysburg College psychology professor Brian Meier and his research team found that people who were high in the personality traits of agreeableness or extraversion were rated by strangers as being more attractive.
Meier's team assessed the personality of 217 men and women.
The photos of these men and women were shown to unacquainted strangers who rated their physical attractiveness.
They found that the men and women who had higher levels of agreeableness or extraversion were also rated as more physically attractive even though raters did not know or interact with the individuals.
Meier said: "The results suggest that there is some truth to the 'beautiful is good' stereotype or the 'halo effect.' People have a tendency to think that attractive people also possess 'attractive' qualities - such as being friendly, outgoing, and smart."
He added: "Interestingly, it appears that grooming is a key mechanism. Friendly or outgoing people were also better groomed in the photographs, which made them appear more attractive to others.
"Because the photographs were taken unexpectedly, friendly or outgoing individuals seem to be better groomed on a daily basis, which likely helps them receive the social interaction they desire."
He concluded: "Grooming is a strong predictor of attractiveness that can be easily controlled by the individual unlike more physical characteristics such as weight or skin blemishes. Thus, sociable people seem to already know that a neat appearance goes a long way in drawing others' attention."
The paper titled "Are sociable people more beautiful?," has been published in the Journal of Research in Personality.