To get a better understanding of some of these seemingly non-sensical signs, let's take a look at what science can tell us about absurdity.

Nathan A Heflick, Ph.D., is currently a senior lecturer in psychology at the University of Lincoln in the United Kingdom. To understand absurdity, he says, we must first know what's a schema.

"A schema refers to people's expectations," he wrote in Psychology Today. "So for instance, one's schema for a card deck is that hearts are red, and spades are black. If you were to play with a deck with the colors reversed, this would disrupt your schemas."

Cognitively, schemas are important because they enable us to process and use a ton of information in the world very quickly with minimal effort and fuss. "To put this in perspective, imagine going some place entirely new where you have no idea what to expect. The sheer effort exerted in trying to function without your usual schemas would be exhausting."

Science shows that we are motivated to maintain our existing schemas. For example, the meaning maintenance model by Steven Heine, Travis Proulx, and Kathleen Vohs, says that people's need for things to make sense (to be meaningful, and consistent with their schemas and expectations) is so strong that when it is disrupted, people act with increased efforts to restore their "meaning frameworks."

In one study Proulx and Heine exposed participants to a story written by Franz Kafka. The story starts out with a clear storyline (a doctor heading out to help with a child's toothache) and ends with a series of meaningless statements.

As Heflick pointed out, from the perspective of the meaning maintenance model, this should elicit an increased need to affirm and validate one's sources of meaning (one's schemas and expectations).

And in the study, this occurred through an increased ability to learn a new language. Specifically, participants were exposed to a list of digits and then were more likely to detect patterns in a made-up grammar system when they had just read the absurd, meaninglessness story by Kafka.

"Put differently, when people had their schema threatened by reading something that did not make sense, they responded with an increased capacity to learn," Heflick explained.

The psychologist said this research has several interesting implications. "For starters, schemas serve many useful functions. But, when schemas are broken, they increase learning. So, presumably, people need to overcome their natural tendency to protect their schemas to maximize their ability to learn."

In practical terms, this could suggest that when people isolate themselves from outside information to protect their schemas (such as only watching or reading things that verify their views), they hinder not only their ability to learn about other perspectives (through a lack of information) but also their ability to learn anything novel or different.

So when you think about it, the folks behind these signs are actually doing a public service. They're increasing everyone's desire and ability to learn. I know, it sounds like a stretch, but science says so!