It’s a common misconception that the reason subjects in portraits of yesteryear didn’t smile is because of unappealing looking teeth. In fact, the reason is quite logical: smiling for hours on end is awkward and straining for models. In an essay on the topic, writer Nicholas Jeeves says, “A smile is like a blush. It is a response, not an expression per se, and so it can neither be easily maintained nor easily recorded.” As such, the smile is absent from most historical art and when it does occur, it represents lewdness, drunkenness or sex. With the invention of photography, the smile became a mainstay in portraiture and public appearance—and artists could reference photographs and smiling for a photo took seconds and minimal effort. “In many ways, its reception throughout art history has said a lot about our willingness to really see ourselves, and one another,” Artsy’s Julia Wolkoff writes about the elusive expression. Read more there.