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How Humans Learn: Lessons From the Sea Squirt

Our bodies are an important part of the learning process.

The sea squirt has a fascinating life. Starting off as an egg, it quickly develops into a tadpole-like creature, complete with a spinal cord connected to a simple eye and a tail for swimming. It also has a primitive brain that helps it locomote through the water. But, the sea squirt’s mobility doesn’t last long. Once it finds a suitable place to attach itself, whether it is to the hull of a boat, underwater rocks, or the ocean floor, it never moves again.

Although it’s hard to tell by looking at their spongy bodies, sea squirts are members of the phylum chordata, which includes animals with spinal cords like fish, birds, reptiles, and humans. But, unlike humans, sea squirts don’t keep their brains and spinal cords forever. What’s most fascinating about the sea squirt is that, almost as soon as it stops moving, its brain is absorbed by its body. Being permanently attached to a home makes the sea squirt’s spinal cord and the neurons that control locomotion superfluous. Once the sea squirt becomes stationary, it literally eats its own brain.

The life of the sea squirt tells us something interesting about what brains may have evolved for—to orchestrate and express active movement. But, even though the sea squirt’s story suggests a tight coupling of body and mind, this relation is often ignored. Take mainstream education in the Western world. Despite the fact that the information we encounter is taken in by different senses—the eyes, ears, or even touch—psychologists and educators often characterize the storage of this information as abstract symbols on our mind’s hard drive. The logic, then, is that it doesn’t really matter how the information gets in. Lesson plans are designed with the adult sea squirt in mind, as if the body is unnecessary, with students permanently affixed to their desks.

This stationary view of education is really mind-boggling if you reflect for a moment on the way in which we tend to learn in the first place. Take language as an example. Learning language involves a lot of activity. A mom might hold up a cell phone, hand it to the toddler, and point and say “phone,” or model waving “hello” by literally waving. Most of the words that kids learn are tied directly to the objects the word refers to and, more often than not, the kids get to hold and manipulate the objects they are learning about. But, in most standard classroom reading lessons, teachers aren’t connecting what kids are reading to the world. Even when using picture books, teachers are often focusing so closely on what the words sound like that they seldom point to the pictures that depict the objects and events the words refer to. Reading is taught in a stripped-down fashion, devoid of the body.

Why is this a problem? One reason is that this doesn’t seem to be how our brains work. When we read, we tend to activate the same sensory and motor brain areas involved in doing what we are reading about. When people make small body movements in the fMRI scanner, say moving their feet, fingers, or tongue, they activate regions in the sensory and motor cortex involved in moving these body parts. Most interesting, when people read words associated with the leg, mouth, and arm (“kick,” “pick” and “lick”), they activate these same sensory motor brain areas. Both moving your foot and understanding the world “kick” are governed by similar areas of the motor cortex. It’s hard to separate the reading mind from the doing one.

Teaching words divorced from the objects and actions they refer to just doesn’t reflect how the brain is organized. And, it certainly doesn’t reflect the story of the sea squirt. Our body and mind are tightly connected. The body is an important part of the learning process.