Soul face, Parkinson face
Why are Trump and Sanders winning?
Aside from the basic point that both are telling the truth once in a while, I think there's a more visual or personal quality that unites them.
Both have FACES.
After years of working with computer graphics, and years of dealing with anatomy, I have a pretty good sense of what it takes to animate a face.
In CG terms, Trump and Sanders have non-default faces, while all the others are default. Locked at zero. Fresh out of the box. Nobody has adjusted any of the morphs on Cruz's face. Clutch Cargo.
In anatomical terms, Trump and Sanders have a normal display of emotions. Their muscles are responding correctly to what their souls are doing.
All the others seem to exhibit Parkinsonian 'flat affect'. (Parkinsonian in
both senses!) Occasionally you'll see their faces being pulled mechanically by external vectors like focus groups or consultants or Sheldon Adelson, but the motion is out of sync and jerky.