Neuroscientists say our brains are flexible organs that harden over time. When one of our 100 billion neurons sends an electrochemical charge to another neuron, it opens a new path in the brain. If the neuron repeats this signal enough times, the path widens into a road and then a runway. The more we think about something, the more that thought becomes embedded in our brains. It might be easy to change our minds when experiencing a new thought. It’s more difficult when that thought has built a highway in our heads.