Sanders' Smile is 'Genuine' But Clinton is Hiding Something, Body Language Expert Says

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There has been much debate about the state of Ted Cruz's face.

The Republican presidential candidate looks like Grandpa Munster, some online pundits say. His smile doesn't reach his eyes, others have said.

Read: Trump's Family Celebrates His New Hampshire Win As He Heads to South Carolina

So what's in a politician's facial expression? INSIDE EDITION spoke to a body language expert, following recent discussions including a Psychology Today post, about what cues can be derived from a candidate's smile.

Tonya Reiman tells IE that Democratic candidate Bernie Sanders "is authentic. He's always genuine ... He's got the creases, the cheeks are raised."

Hillary Clinton, not so much, Reiman says.

"She smiles just to mask whatever emotion she doesn't want you to see," Reiman said. "This is known as a social smile. There's not much movement around the eyes and the lips aren't really elevated."

Cruz, she says, seems to be sneering.

Read: Sanders Wins in Tiny New Hampshire Village With 4 Votes, Hillary Clinton Gets 0

"When he smiles the initial impression is that of a sneer or a contemptuous grin. So what happens? We think of that as sarcastic and we start to dislike him."

Watch: Donald Trump Slams Ted Cruz,  Accuses Him of Committing 'Fraud' in Iowa