Over the years, many theories have popped up trying to explain why smiles are so rare in old photographs. The most popular ideas were that people didn’t want to show their bad teeth or, alternatively, that it was impractical to hold a smile during the long exposure times of early cameras. While these issues might have prevented some from grinning, the major reason for the serious looks was because most people thought smiling made them look ridiculous.

At one point in time, it was largely believed that people didn’t smile in old photographs because they were hiding rotten or missing teeth, which were all too common prior to the days of modern dentistry. It turns out this wasn’t really true, since there were plenty of individuals who had fabulous chompers, yet still kept their mouths shut during pictures. Not to mention, humans can smile without revealing their teeth. Furthermore, bad teeth were so ordinary that they weren’t necessarily seen as unattractive. In fact, Lord Palmerston, the British Prime Minister of 1855, was considered devastatingly good-looking even though he was lacking several obvious teeth.