In pictures: US candidates' body language

But the expert adds that in the past Mrs Clinton has been "one of the worst offenders" for showing emotion which comes across as rehearsed.

Ms Wood says that during the New Hampshire contest, Mrs Clinton's body language shifted to "warmer cues", designed to increase her likeability.

She smiled more, showed the palms of her hands and appeared to "open her heart" by making expansive arm and hand gestures away from her chest, the expert says.