Charismatic actor and activist George Clooney.

London - Scientists believe they have discovered why some people have a more magnetic personality than others.

For charisma is based on how quick-witted you are, research shows.

People with rapid-fire reactions were rated as more charismatic by their friends – regardless of whether or not they were highly intelligent or had any other personality traits.

The researchers, from the University of Queensland in Australia, suggest in the journal Psychological Science that “mental speed” allows an individual to consider a wide range of answers before making a humorous response.

But the study of 417 participants, who were rated by their friends on how charismatic and funny they were, found that being quick-witted was not necessarily associated with other social skills, such as being good at handling conflict or interpreting others’ emotions.