The image shows a pair of computerised 'averaged' facial photographs taken from real people's pictures:
http://rotter.name/User_files/nor/47fdc6f570cc14251.jpg
http://rotter.name/User_files/nor/47fdc6f570cc14252.jpg
According to the research, the face on the right is of someone who is more likely to be interested in a short-term sexual relationship whilst the one on the left is more likely to be interested in a long-term relationship.
Reuters