Dr Harry Witchel, Discipline Leader in Physiology at Brighton and Sussex Medical School, run by the universities of Brighton and Sussex in collaboration with the NHS, examined the two leaders' movements and gestures during their keynote speeches at their parties’ recent conferences.
He concluded: the Prime Minister came across as aggressive while the Labour leader appeared an over-confident technocrat.
Writing today in The Conversation, the news site written by academics, Dr Witchel interpreted the meanings of the minutiae of body movements: "Cameron's most revealing gesture is found in his face. His thin lips regularly purse inward at certain times in a particularly idiosyncratic way. Thinning lips are typically a sign of anger but the inward movement of Cameron's lips, as if he was about to bite his lip, is actually a sign of anxiety.
"Before becoming Conservative leader, Cameron was known for having a fear of public speaking. He used to blush uncontrollably in front of a crowd but has managed to control that sign of anxiety. His lip movements reveal that his anxiety still hasn't been completely vanquished though."
On Miliband: "His hands often assumed another central position, steepling in front of his abdomen, which is a sign of technical confidence. This position is often seen in engineers and experts, and is even reminiscent of Miliband's brother David.
"In some ways, though, Miliband's tendency to position his hands centrally is a defensive mechanism. They are the hands of a geek in the playground, worried that a bully is about to kick a football at him."
Summing up, Dr Witchel said: "These two leaders are different in so many ways and their body language tells us what kind of prime minister they are, or would be. Many of their actions and positions on stage are well-rehearsed but others are impulsive. All confirm that Miliband is open while Cameron is commanding.
"Their bodies give away tell-tale signs of nerves while public speaking, but neither gave off signs that they are unfit for the job of leader."