Barbara: Can you tell that we like to use metaphors? But wait a minute, you might ask. What is a metaphor? Barbara: A metaphor is a comparison between two things. One thing is something you are familiar with, like an ocean wave. The other thing is something you may not be familiar with, like an electrical wave. Metaphors allow you to connect what you already know to the new concept you’re learning. This helps you learn faster. Obviously, an electric wave is not the same as an ocean wave. We also know a neuron is not a space alien, and a dendritic spine is not a toe. They just share some similarities that make it easier for you to understand certain ideas. In these videos, I’ll just use the word metaphor—it’ll make things simpler for us. Technically, though, I’m sometimes using an analogy or simile. Coming up with a creative metaphor is one of the best ways to learn a new concept or share an important idea. Terry: When you think of a metaphor for a concept, a pre-existing set of brain-links is activated. This older set of brain-links allows you to more easily think about the new concept using ideas you already understand. Greg: Ultimately, this means that, just by thinking of a good metaphor, you’ve already started understanding aspects of the new concept! Metaphors help you to get key ideas faster. Greg: (This is related to something called “neural re-use” theory. A metaphor allows you to re-use an idea you have already learned to help you learn a new idea.) Barbara (voice only): At some level, metaphors stop working. For example, our metaphor of a space alien sending a shock to the next space alien doesn’t explain synapses well if you look closely. That’s okay, though, because whenever a metaphor stops working, you can just throw it away and get a new one. Terry: Also, sometimes it’s nice to have several different metaphors to help you understand a single idea. We used three different metaphors to help us understand how neurons connect together. We said it could be like a brain-links, like space aliens shocking one another, or like a mouse path in a forest. Pretty cool! Greg: In our videos, you’ll meet many metaphors: robots, links, mice,and octopuses. The metaphors give you an easier way to understand key scientific ideas. Don’t worry if a metaphor might seem strange. Sometimes wackier metaphors help you to more easily open your mind to the new idea you’re trying to learn. Wacky metaphors can help you remember better, too! And now at last, to finish the story of Santiago Ramón y Cajal and how he changed! Barbara: I’m Barbara Oakley Greg: I’m Greg Hammons Terry: and I’m Terry Sejnowski Barbara: we, and Arizona State University, wish you happy learning!