It may come as some surprise to hear us say this, but when it comes to your smile, people aren’t necessarily thinking of your teeth. Instead, they may be thinking of your lips. In fact, our lips seem to be the part of our anatomy that is most closely related to our smile in our mental framework.
Or, at least, it’s the one most closely associated linguistically with smile, according to data from Google’s Ngram Viewer, which allows us to look at word usage in many of the English books catalogued by Google Books, about 20 million catalogued, of which about 6 million are used in Ngram Viewer.
What Google Ngram Can Tell Us
Google’s Ngram Viewer tells us not how often a word is used, but how large a fraction of the total words being used the word occupies. Curves are plotted as percentages of all words used, which allows the curves to show trends across time when the total number of printed words may rise and fall.
Google’s Ngram Viewer is a powerful linguistic tool that we are only now beginning to understand. By instantaneously searching the 5 million catalogued books, the Ngram Viewer reveals patterns about language use that tell us how people think about the ideas represented by the words.
When people use words it shows what’s on their minds, and it often reflects real-world events. For example, the curve for “depression,” shows a significant spike in 1929, when the great depression began. The curve for “war” has two tall spikes: 1910-1927 and 1936-1952, reflecting both the anticipation and aftermath of both World Wars.
Plotting Your Smile
So let’s explore how people think about a smile, and what it means for you. Graph 1 shows a plot of several words from 1700 to 2008.
It includes “smile,” “teeth,” and “lips,” but also some control words that are intended to distinguish trends related to facial descriptions from those specifically about smiles: “cheeks” and “nose.”
Just looking at the graph, you can see very clearly that teeth and smile are not very closely related at all. They follow very different patterns.
However, when you look at the curves for smile and lips, the two show a rough parallel that is fairly striking.
The parallel is perhaps most striking around 1900 (Graph 2), when smile and lips both show a remarkable rise together. When you look at the curves for cheeks and nose, they also experience a minor rise around 1900, associated with increased attention to facial appearance, no doubt, but they are nothing compared to the parallel curve of smile and lips.
Also striking is how much the curves mirror one another for the period from 1940 to the 1970s (Graph 3), when they are both in decline and come to an almost identical rate of usage at one point.
Graph 4 shows the terms’ usage from 1950-2008, allowing a closer look at the parallel between the smile and lips lines, including the swayback they form from 1995-1999, and the parallel bump up around 2005.
Your Lips Frame the Smile, but Your Teeth Are the Smile
When other people are looking at your smile, they may think of your lips, but when you are making your smile, you likely think of your teeth. And when you are reluctant to show them, you may be less likely to smile, and less likely to enjoy the pleasant company of friends and family.