Have you ever heard of the Goldilocks Principle?

It’s named after the fairy tale Goldilocks and the Three Bears, in which the porridge is not too hot, not too cold, but just right. It’s become an ideology for something that needs to sit between extremes. It’s used in many fields, but most famously in astronomy: the Goldilocks Zone is the ideal orbiting region for a planet, one that allows water to remain liquid. That’s where Earth is and where NASA, in distant star systems, is looking for exoplanets that could host life.

The Goldilocks Principle is one of many effects, laws and disorders named after stuff from children’s books. There’s something about the simpleness of a bedtime story that fascinates academics the world over. Who gets more ‘likes’? No doubt, Lewis Carroll’s Alice in Wonderland. It has inspired at least four of these things.

The first one has the most obvious name, but it’s a very peculiar condition. It’s called the Alice in Wonderland Syndrome and it’s a neurological disturbance that messes with the perception of size. Objects may seem exaggeratedly big or impossibly tiny, as if you drank one of Alice’s potions that made her bigger or smaller. But this is no benign trip, as it is accompanied by strong migraines, high fever and nasty hallucinations.

The Cheshire Cat effect also has to do with perception, but it’s not a condition: it’s a strange quirk of binocular vision wherein you will see a person magically disappear, just like the infamous grinning cat, while one of your eyes is pointed straight at them. You can experience this yourself with the help of a friend, a small mirror and a white wall, following the instructions in this very clear, if a little slow, science project video.

There are many forms of psychotherapy, each one following a different school. Some believe that they all produce the same results, regardless of procedural differences. This controversial hypothesis is called the Dodo Bird Verdict, after the running competition organized by the Dodo in the book, in which there are no losers: “Everybody has won and all must have prizes”.

Biologists also have borrowed from Alice. The very intriguing Red Queen hypothesis is an evolutionary scenario in which two competing species (such as prey/predator or parasite/host) both keep adapting at full pace to each other’s mutations, in an evolutionary arms race. The passage it refers to is actually from Through the Looking Glass, in which Alice and the Red Queen furiously run but do not progress an inch, and the latter remarks: “It takes all the running you can do, to keep in the same place”.

It’s not surprising that psychology has such a fondness for Alice: even if the main underlying theme of the book is math (Carroll was a math teacher in Oxford), the mind-related matters are much more readily apparent. The characters in Alice are so riddled with disorders that, put together, they summon practically every demon in the psychological bestiary: Alice is violently schizophrenic, the Red Queen is bipolar, the Mad Hatter has the more rare adult form of Attention deficit hyperactivity disorder (ADHD), and the White Rabbit exhibits severe anxiety and possibly some form of Obsessive-compulsive disorder (OCD). Some believe that the novel itself is a description of the reality and dynamics of Borderline personality disorder, from which Lewis Carroll is thought to have suffered.

I don’t want to go among mad people, Alice remarked.

Oh, you can’t help that, said the Cat. We’re all mad here. I’m mad. You’re mad.