Scientists have modelled the specific physical attributes that underpin our first impressions. Small changes in the dimensions of a face can make it appear more trustworthy, dominant or attractive. Dr Tom Hartley, a neuroscientist at the University of York and the study's senior author, said the work added mathematical detail to a well-known phenomenon. 'If people are forming these first impressions, just based on looking at somebody's face, what is it about the image of the face that's giving that impression - can we measure it exactly?' To make the calculations, each of 1,000 face photos from the internet was shown to at least six different people, who gave it a score for 16 different social traits. Overall, these scores boil down to three main characteristics: whether a face is (a) approachable, (b) dominant, and (c) attractive.