THE word “cool” has been cool for a long time. Originally associated with temperature, by the 16th century the term had evolved to describe not just the atmosphere, but also an internal state of calm, almost icy composure. And by the late 1800s it began to signify style and hipness and some of the other meanings with which it is associated today. Now cool is used as a synonym for almost anything good. Music can be cool and restaurants can be cool. Every so often even a minivan seems cool.
But not all words and phrases persist. In the 1940s, dress snappy and someone might say you looked “spiffy.” In the 1950s, people might say you looked “swell.” These days, teenagers might say you’re “on fleek.” What was once “awesome” is now “dope.” Tell someone today that they look spiffy and people will think you’re caught in a time warp.
Language is constantly evolving. Certain words and phrases catch on and become popular while others die out and wither away. So what leads some phrases to become more successful than others? Why do some survive the test of time while others die out?
There’s no record of every time someone utters a certain word or phrase, so to study these questions, my colleague Ezgi Akpinar and I turned to the next best thing: books. For hundreds of years, of course, books have documented the words and phrases used to express different ideas. This includes everything from Shakespeare‘s sonnets to Jane Austen’s description of the landed gentry, and many thousands of works by unknown authors in between. Books provide a written record of culture, a constantly evolving collection of snapshots of what things were like across time and space.
There are multiple ways to convey the same thing, and phrases with similar meanings often act as substitutes, competing for usage. A not-so-friendly person, for example, can be described as unfriendly or cold. An intelligent student can be described as smart or bright. For each of these pairs, one of the phrases relates to the senses (i.e., cold person or bright student) while its semantic analogue (unfriendly person or smart student) does not.
While this might seem like a minor difference, it actually has a big impact on linguistic success. Compared with their semantic equivalents (e.g., unfriendly person or smart student), we found that phrases that relate to senses in metaphoric ways (e.g., cold person or bright student) became more popular over time.
In the 1800s, for example, people used the phrase “sudden increase” to refer to a quick rise in something. But the phrase “sharp increase” was introduced around 1900 and is now much more popular. Similarly, whereas people used to use the phrase “promising future” to suggest that good things would be forthcoming, the phrase “bright future” soon took over and now is used 2.4 times as frequently.
Such sensory metaphors are more successful because they’re more memorable. Sensory metaphors help express abstract concepts by linking to direct bodily experiences in the physical world. Calling an unfriendly person “cold,” for example, suggests that, like a frosty winter, he or she is not very inviting. Calling an unpleasant note “sour” suggests that it makes you wince, as would a tart taste. These links make sensory metaphors easier to retrieve from memory. If you give people a list of sensory metaphors and other phrases that mean the same thing, we found, sensory metaphors are 50 percent more likely to be remembered 10 minutes later.
Social transmission further exacerbates this advantage. People are more likely to remember sensory metaphors they’ve heard, which makes them more likely to use them in the future. This, in turn, increases the chance that other people hear the phrases and later use them as well.
Taken together, these findings help explain not only what becomes popular, but also why certain phrases persist. And they highlight the important role that our senses play in the process. Language may seem like something that is out there in the world, but it is constantly being shaped and refined by the way our minds are built. Just as natural selection molds finches’ beaks and giraffes’ necks, psychological processes of memory and transmission shape language. This cultural selection determines what succeeds, and what fails.
In this case, our senses may help explain why “cool” has been hot for so long.