Trump's 'surprise' is acted — it's completely feigned.
• forehead is relaxed (and lowered)
• eyebrows are also relaxed
• eyelids are partially (mostly) closed,
• furrows in each of his lower eyelids are concave-upward
• mouth corners are pulled significantly upward
• cheek muscles (zygomaticus major) are contracted and bunched upward
• only his upper teeth are visible
All of these are components of a true smile of joy-happiness. At this moment, Trump hears only the cheer of the crowd and is delighted.
A. Peripheral Vasodilation — blood vessels near surface of his skin on his face are growing wider in diameter. This physiology is involuntary &, in this emotional context, is a form of blushing.
C. Increased Abdominal Pressure (contracting one's "stomach" [abdominal musculature])
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