How does the human brain develop? At birth, it's only a quarter of the size of an adult’s. A baby has 50 trillion neural connections, while a fully-developed person has 500 trillion. These are the synaptic pathways responsible for how we act and think. Yes, you are simply your brain, and it’s just a hunk of electricity controlling the machine that is your body!

But what would happen if after birth, the human body continued to grow normally, but the maximum level of cognition we could reach were equal to that of a 3-year-old? It’s between 3 and 5 years old when personality starts to develop. With the brain development stopped at a 3-year-old’s level, we would have very different personalities than we do now. And we’d more than likely live.. in trees!

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