Physiological signs and the polygraph critique

The BBC hit series Traitors is a show that depends on being able to accurately spot a liar, but are any deception detection methods actually backed up by science? Madeleine Finlay speaks to Timothy Luke, a senior lecturer in the department of applied psychology at the University of Gothenburg, to find out whether sweating, nervous tics and reduced eye contact really can alert us to deception – and if not, what can?