Smiles brighten up our days, and their forms are manifold. They are important in the arts, literature, and music. A very well-known example in literature certainly is the Cheshire Cat from Alice in Wonderland by Lewis Carroll. Probably the most discussed smile in art is that of the Mona Lisa: is the smile as enigmatic as many claim or did she suffer from bruxism¹, as the Italian doctor, Dr Filippo Surano suggested in 1999? The most popular 'smile' for Internet users worldwide is certainly the simple smiley. It is an emoticon, used to express the writer's feelings in absence of the body language we rely on in a face to face conversation.

Today, there are thousands of variations to express different emotions, but they're all derived from 'the' Smiley² - a bright yellow button with two black dots and a black half-circle pointing upwards, representing the eyes and the mouth. The usual code for it is either :-) or :). This smiley was allegedly created by the American Harvey Ball in 1963, as a logo for an insurance company. It would take until the early 1970s for this smiley to be marketed and make some people millionaires. Companies still use some form of smiley or smile as a logo or slogan to indicate that their services or products are customer-friendly.

What is it about a smile that it makes people so attractive, usually causing a similar reaction in those we're smiling at? Why do photographers insist that you should smile, often by asking you to say 'cheese'? Why is it that a face showing lots of smile-wrinkles³ is thought to be a sympathetic face?

A smile is the shortest distance between people.
It doesn't cost anything, yet it gains so much.
It makes the addressee richer without making the donator poorer.
It's as fast as a flash, but the memory of it is often everlasting.
Nobody is rich enough to do without.
Nobody is too poor to afford it.
It brings luck to the home and is a token of friendship.
It means recuperation for the tired,
Encouragement for the fainthearted,
Cheering-up for the sad,
And is the best means against annoyance.
You can neither buy it nor request it,
Neither borrow it nor steal it,
Because it gets its value only when it is given away.
There's nobody so much in need of a smile
Like the one who doesn't have a smile to spare himself.
-Anon

An Inherited Feature

The ability to smile (among others) distinguishes humans from animals; not even the great apes with whom we share a lot of features can smile consciously. An animal showing its teeth may give the impression of smiling, but this usually is meant as a threat or as a sign of submission. Humans showing a broad smile or a grin often expose their teeth (and risk showing poor teeth and/or what they ate for dinner at the same time). 'To show one's teeth', though, is an idiom for becoming hostile or threatening, just like in the animal world. It is said that a smile can't be learnt. Researches found that a smile is a natural reaction to certain situations throughout all cultures and that it is the most commonly used facial expression. A human baby is born with the ability of a whole range of (not only) facial expressions to express how it is feeling. Most parents eagerly wait for the first smile of their newborn. Some may even have been lucky and caught a glimpse of their baby smiling in the womb during an ultrasound scan. We can distinguish between three different sorts of smile:

The Reflex Smile

This is what it says on the tin: a mere reflex to stimulation like tickling, stroking and voices. Most often, it will be the higher-pitched, loving voice of the mother that will cause the newborn to smile. This reflex requires that a myelin sheath⁴ has been built around the required nerve tracts. Because of its nature, the smile can have a startled or even anxious quality, depending on the stimulus.

The General Smile

This smile will often occur during the fourth or fifth week after birth. It can be considered as a welcome, as the newborn is now able to differentiate between a stern or a smiling face. Although still mostly a reaction to the parents' voices or smiling faces, it can also be a reaction to any friendly, sympathetic face, hence we're talking about a general or 'unspecific' smile. Gradually, because of the feedback this repeated smiling usually creates, the baby's smile will become broader and will last longer.

The Special Smile

This smile occurs from when the baby is aged between five and seven months. Like every genuine smile, it is also known as the Duchenne smile⁵'. It is reserved for a few select people such as parents, older siblings or people who are in close and regular contact with the baby. It is a conscious smile which is given to the baby's favourite persons. As the smile is congenital, even blind babies smile, but these smiles aren't as distinct as those from babies who are not blind, because they can't see the feedback. The response to the baby's smile is essential for the bond between the baby and the caring persons. It is said that babies of depressive mothers will have more problems emotionally than other babies. A baby's smile is still candid, as it hasn't yet learnt to use it for, say, diplomatic reasons. Psychologists have researched the reason why the smiles of babies are so irresistible, and have offered the following explanation: a baby's smile is so irresistible because that's the only means of the baby to keep the loved person for a while longer, a bit like pulling their sleeve.

Ways to Smile

There are many attributes allocated to a smile, though not all of them are positive. Below is a list of the most common types of smile.

• Shy smile
• Tired smile
• Resignated smile
• Nervous smile
• Diplomatic smile
• Business-like smile
• Fake smile
• Relieved smile
• Sincere smile
• Special smile
• Happy smile
• Radiant smile

...To name but a few. Phrases/idioms around the smile include the following:

• Break into a smile
• Crack a smile
• Smile on
• Fortune's smile
• Smile at
• Put a smile on
• Smile one's tears away
• Keep smiling

A smile is said not only to change the facial expression, but causes the brain to produce endorphins which lower physical and psychological pain as well as the stress hormone corticotropin, and increases general well-being. The effect is used as the basis of 'smile therapy' for sad and/or depressed people. A genuine⁶ smile can break the ice; it can give comfort and warmth and is generally believed to denote friendliness. The first impression people will get of you may well depend on whether or not you're smiling.

It's not only the smiling person who profits from smiling, as a recent study demonstrated. In many cases, the recipient will smile back, hence profiting from the aforementioned benefits. Smiling is contagious. Even looking at a photo of friends or family smiling at you works - go and try this, you'll inadvertently smile back!

Smile Campaigns and Slogans

• Harvey Ball initiated the World Smile Day which is on the first Friday in October every year, and took place for the first time on 1 October, 1999.

• The 'National Smile Month' (UK) isn't exactly about smiling for smiling's sake, but to raise awareness of oral hygiene.

• 'Ein Lächeln für Hamburg' (A smile for Hamburg), is the slogan for the campaign the city of Hamburg, Germany, initiated to motivate its workers to smile more at clients and guests.

• 'Don't just travel, travel with a smile' unsurprisingly was the slogan from a travel agency.

• 'Taste and Smile' is not only a logo to advertise sugar, there's also a club of that name and even a booklet with that title.

• 'Smile when you dial' - the 'order' for the employees of an outbound telephone marketing research company, because of the positive results the smile has: it changes the timbre of the voice, hence the called person sort of 'hears' that the caller is friendly.

How many muscles does it take to produce a smile? Opinions on this vary greatly; some say it only needs two pairs of muscles - one pair for the contraction and one to expand. The general consensus seems to be that you use at least 17 muscles for a smile, but more than 40 for a frown. Whatever the exact number, it is much easier to smile than to frown, so go and say 'cheese'.