Body talk: Donald Trump and his many faces

President Donald Trump's words are loud and divisive, but his actions speak even louder, body language experts say.

The world's eyes were on the 45th US President as he was sworn into office in Washington DC and while his words sealed the deal, his facial expressions and interaction with wife Melania provided a parallel subplot.

Even during his election campaign and the primaries, Mr Trump's face signalled to the audience his real intentions.

Behavioural psychologist Dr Peter Collett singled out just a few of Mr Trump's subtle expressions.

The alpha face:

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This is his dominant expression where he lowers the brows, narrows his eyes and doesn't smile.

Dr Collett says Mr Trump's lack of smile is because smiling is an "appeasement gesture", he told Sky News.

"It's a way of signalling you're not a threat and the one thing Trump wants to convey is that he is a threat."

The chin jut:

donald trump united states president

Men with large chins tend to have more testosterone meaning they're "much more dominant and much more aggressive", Dr Collett says.

He says it means he's showing everyone "he deserves to be in charge".

A 2015 study found people see those with broad faces as aggressive because it's a marker of high testosterone exposure in the womb.

It says cues widely used in judging dominance and strength are the size of the chin and jaw.

The zipped smile:

donald trump united states president

When Mr Trump does smile, he sometimes uses his 'zipped smile' which makes it look like he has a big mouth.

Dr Collett says research suggests men with large mouths tend to dominate and run organisations much like Mr Trump has done throughout his business career.

A March 2016 study from the Journal of Experimental Psychology showed people with wide mouths are perceived by others to be better leaders than those with narrow mouths.

It says mouth width, which correlates with the tendency for physical combat in primates which could therefore be linked to perceived dominance and a greater social ranking. 

General exaggerated expressions:

donald trump united states president

The protrusion of his lips and his animated gestures are similar to mothers when they talk to their babies.

These are used by mothers to attract attention and make sure they're understood  Dr Collett says Mr Trump could be doing the same because he "doesn't really believe people fully understand him".

The puckered chin:

donald trump united states president

When Mr Trump puckers up his chin, he's feeling vulnerable and threatened as if imagining they're about to get punched.

But Mr Trump isn't the only one whose body language people are reading into. It was First Lady Melania Trump's smile which has people intrigued.

During the inauguration ceremony, Mr Trump looks behind him to the First Lady which elicits a wide smile from her. But when he turns back, her smile immediately turns upside down.

A clip of that moment was spread through social media along with the hashtag #freemelania.

It wasn't the only moment of the inauguration which had people thinking their marriage was strained.

As he walked out of his car to meet the Obamas, Mr Trump strode ahead with Melania walking behind him carrying a gift for the outgoing president and first lady.

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The Obamas then escort her inside, their hands on her back, as Mr Trump walks alone into the White House.

At the inaugural ball, the new President and first lady shared an awkward dance where at one point, Mr Trump pointed at the crowd in delight.

Communication and body language expert Susan Constantine told news outlet Mic that if people didn't know they were married, they wouldn't have guessed they were.

Another body language expert, Patti Wood, explained the White House Obama meeting further.

"Not only did he not wait, he went up the stairs and greeted the Obamas, he didn't even look back to see if she was there or help her up the stairs."

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Melania pulled away from her husband during their first dance, which Ms Wood said "typically says 'I don't want to merge with you as a partner'".

It's a stark contrast to the Obamas who shared a few affectionate moments during inauguration day - hand holding, a wink and a smile.

Ms Constantine says it shows the difference between the presidential couples.

"Melania is an object to [Trump]. I don't see any warmth or true love and compassion in that relationship whatsoever," she told Mic.