The eyes may be the window to the soul, but a smile can reveal more about a person than first thought.
A body language expert has told MailOnline the tiniest tweak to a smile can change how a person is perceived - from looking up to appear flirtatious, to lowering the eyebrows to look more dominant and powerful, for example.
Dr Peter Collett has pinpointed six types of smiles from the genuine ‘Duchenne’, where the corners of the mouth are pulled up and the muscles around the eyes contract, to the knowing, wry smile, The Daily Mail reports.
While the ‘raised-brow’ smile suggests submission, keeping eyebrows level can make the smile more powerful, which could prove useful when negotiating a business deal, or in a job interview.
‘In the realm of facial expressions there’s a big difference between lowered and raised eyebrows, with the former signalling dominance and the latter signalling submission,’ Dr Collett,a psychologist from Oxford, said.
‘When someone smiles with both their eyebrows raised it shows that they don’t want to dominate the situation and they want come across as unthreatening.’
A full smile is called a Duchenne smile - after 19th century anatomist Duchenne de Boulogne, who produced a ground-breaking study of the muscles involved in facial expressions of emotion. The openness of the expression gives the impression that someone is genuine.
Dr Collett added that the wide open smile is a ‘clever way of getting other people to share one’s positive feelings.'
‘When someone tilts their head back slightly and opens their mouth wide they look like they are laughing rather than smiling.
'Because laughter is so contagious, those of us who see someone doing this are much more likely to be affected by the display and to feel that we share their positive emotions.’
Meanwhile, the ‘look-up’ smile can be used to appear seductive and flirtatious. ‘Some people have a habit of lowering their head slightly when they smile,’ said Dr Collett.
‘Unconsciously, this gives the impression that they’re shorter than they really are and that they’re looking up towards the person they’re addressing.
'This, coupled with the suggestion of embarrassment, makes the look-up smile especially flirtatious, which explains why it’s favoured by women when they’re dealing with impressionable men.’
Some people smile asymmetrically and when they look directly at someone, this wry smile can appear knowing and tells someone that you’re aware of something, or that you share a secret.
‘Smiles come in all shapes and sizes - some are involuntary, others deliberate, and they’re linked to a rich vocabulary of subtle messages,’ continued Dr Collett.
‘By taking a closer look at how people smile we can gain a much better understanding of what they’re feeling, and in some cases what kind of person they are.
'And of course the same principle applies to your own smiles.’
A study of 2,000 people commissioned by Wrigley’s Extra White Bubblemint, found that just over half of women think a smile is the most attractive trait in a man that they are meeting for the first time.
Men also place more importance on a woman’s smile than her chest, bottom or legs.
However, 67 per cent of women and 53 per cent of men said that they worry about their smiles.
The survey, released to coincide with the launch of National Smile Month today , revealed that there’s nothing better than someone directing a genuine smile straight at us to encourage us to return the favour.
A total of 58 per cent of people smile when they receive a compliment, 37 percent when looking at family photos and one in five when they are praised at work.