Would you be more creeped out by an expressionless robot-looking robot, or an expressive human-like robot? We imagine it could be rather disturbing if robots started to look and act more human.

Nicole Lazzeri from the University of Pisa, Italy, and her colleagues have designed a "Hybrid Engine for Facial Expressions Synthesis" (HEFES) which is a facial animation engine that gives realistic expressions to a humanoid robot called FACE.

The appearance of this FACE robot was modeled after one of the team's wives. Lazzeri says "It's really realistic," as he presented the work at BioRob in Rome last month.

The team placed 32 motors around FACE's skull and upper torso to mimic a myriad of expressions that human face muscles are capable of achieving. To create expressions, they used a combination of motor movements based on a system (Facial Action Coding System - FACS) created over 30 years ago which codes facial expressions in terms of anatomic muscle movements.

The team evaluated the accuracy of their expressions by asking five autistic and 15 non-autistic children to identify a set of expressions performed first by FACE and then by a psychologist. Both groups were able to identify happiness, anger and sadness but less able identify fear, disgust and surprise.

Watch the video below to see FACE in action: