WHY DO WE SMILE?

Smiles are generally accepted as a universal facial expression of happiness or joy. We get instincts about which smiles are more genuine, are more felt than others, and which are more forced and more politely construed. Find out whether smiles are a social reaction- something learned amongst society- or whether there’s an actual biological reason why, when we are given a positive stimulus, our cheeks bulge and the corners of our mouths turn upward.

started with the understanding that because it would be difficult or impossible to define happiness on an individual level, which taking to be the stimuli of the smiles themselves, the results would have to be more generalized and the findings would probably be somewhat controversial and less conclusive.Smiling was more directly linked to a physical, neurobiological response than to social interactions, because there had to be some reason why even the most creative and brilliant of thinkers followed the rest and smiled to show pleasure.

The movement of the zygomaticus major muscle near the mouth, and the orbicularis oculi muscle near the eyes. It is believed that this smile can only be produced as a result of genuine positive emotion, making it involuntary. By contrary, the “Pan American smile” involves only the zygomaticus muscle, and is entirely voluntary, being used more often used to show politeness or mask true emotion (2). This suggests a partial control we have over the kind of smile we show when it comes to realizing that we need to put a smile on our faces for social approval, but little control over smiling about things that genuinely make us happy.

Stroke victims help us understand more of the distinctions between these two types of smiles. When they have had damage to their motor cortex, they often cannot physically concoct their faces into smiles voluntarily, but can smile Duchenne, involuntary smiles, when given a positive stimulus (3). Those having more damage to the deeper-seated basal ganglia can smile on command, but can’t smile as an involuntary reaction, for example, when they hear something they find funny (4). This shows a difference in the roles of different muscles and neurons when it comes to the different types of smiling, suggesting a correlation between not being able smile voluntarily with injury to the motor cortex, and not being able to smile spontaneously with injury to the basal ganglia. The latter is often seen in Parkinson’s disease patients, in whom the basal ganglia degenerate, and there becomes impairment to voluntary movement, with much loss of involuntary movement, including tics, as well (5).

While this shows that different parts of the brain and different brain messengers control different functions, I wanted to combine that with the social factor of smiling in an attempt to put it all together to determine how smiles work. Many studies have indicated that smiling is an innate reaction (1), most often due to happiness. This claim has been made as a result of several factors, including being based on studies of fetuses and children at young ages.

Since 2001, a four-dimensional scanner has been used to allow doctors to see that babies in the womb exhibit facial expressions (6). With the corners of the mouth turned up and the cheeks bulging, obstetrician Stuart Campbell, who’s in charge of this new discovery, says, “what’s behind the smile, of course, I can’t say, but… I think it must be some indication of contentment in a stress-free environment” (6).

The 4D scanner, which also produces 3D images that move in real time, shows that babies start making finger movements at 15 weeks, yawning at 18 weeks, and smiling, blinking, and crying at 26 weeks. After birth, infants do not usually smile until they are 6 weeks old, creating a further interest to survey the womb and why there is this gap of time where no smiling occurs, perhaps because the infant must adjust to its new, less content surroundings. This new information on the subject suggests that perhaps smiling is a reflex to positive feelings, while at the same time can also be a response to hearing social communications from inside the womb.

Another interesting study was done on feral children who live in isolation from human contact and have remained unaware of human social behavior and unexposed to language (7). While there having only been just over a hundred reported cases, these children generally do not smile (1). Isolated from human interaction, they lend an interesting view to the question of why we smile. Since there are so few that are feral, placing great emphasis on this may not be the most constructive, but it is important to keep in mind when assessing how much social interaction plays in the role of a smile.

Instead of the six week gap for these children relearning or regaining the confidence to smile after leaving the womb, they never do, and that’s really interesting. It highly suggests that social interaction plays a large role in either smiling as a reflex, or helping to biologically develop the brain to be able to be able to pick up this kind stimuli reflex.