Have you ever wondered if we all see the same color blue when we look up into the sky? I did, a long time ago when I was a kid without any of my formal education in psychology or neuroscience. The question occurred to me because I loved blue so much and I couldn’t understand why others also didn’t love it. Instead of chalking it up to personal preference, I wondered more deeply about what gives rise to those personal preferences. And I asked, What if we don’t all see the same color blue?