How does your brain know something is real?
It’s a foggy day in New York City. Through my computer screen, I believe I’m seeing and hearing neuroscientist Nadine Dijkstra. But how can I be sure? “We are as much creating our perception of reality as we are perceiving it,” she explains. Rather than rudely asking her to perform a battery of tests to prove she exists, I trust my eyes and ears. It’s an efficient way to live. While neuroscientists might argue the details, most agree that perception—essentially, how we process sensory information to create a coherent experience—involves the active construction of a reality, as opposed to the passive reception of the world around us. For instance, when you see a busy road, you’re actively creating that reality, combining information from your senses (the sights and sounds of whooshing cars ) with past experiences (knowing you’ve walked along this popular boulevard before). Quickly understanding that the automobiles speeding down the street...