Smile too fast? Seems you are insincere

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The speed of your smile can shape the first impressions others have of you, according to new research.
Smiling too quickly can lead others to think that you are insincere, while slow grins appear more genuine.
As part of the research, a team of business advisers examined how smiling can give clients a positive impression. They discovered that a smile, which appears too swiftly and does not extend to the eyes can sends signals that you lack sincerity.
They found that people should avoid three types of grin:
The enthusiast
A huge smile showing all of your teeth and wide eyes can be overbearing.
The big freeze
A constant, practised smile that lacks sincerity.
The robot
A tiny, polite smile that doesn’t display warmth.
“Studies show people perceive a slower, natural smile which floods the entire face to be more genuine,” the Sun quoted Lesley Meechan of the Glasgow-based Go Group as saying.