Your red is my red, at least to our brains

It’s a late-night debate in college dorms across the world: Is my red the same as your red? Two neuroscientists weigh in on this classic “Intro to Philosophy” puzzler in research published September 8 in the Journal of Neuroscience. Their answer is a resounding maybe.

There were two possibilities when it comes to how brains perceive color, says Andreas Bartels of the University of Tübingen and the Max Planck Institute for Biological Cybernetics in Germany. Perhaps everyone’s brain is unique, with bespoke snowflake patterns of nerve cells responding when a person sees red. Or it could be that seeing red kicks off a standard, predictable pattern of brain activity that doesn’t vary much from person to person.

The answer is overwhelmingly the second option, the new study suggests. “There are commonalities across brains,” Bartels says. Along with colleague Michael Bannert, Bartels first monitored the activity of nerve cells spread across visual brain areas as 15 people saw shades of reds, greens and yellows. The team then used those benchmarks to predict what color a person was looking at, based solely on the individual’s pattern of brain activity.

The results show that neural reactions to colors are somewhat standard and don’t seem to vary much from person to person. But these neuroanatomical findings can’t answer the question of how it feels to see red, Bartels says. How brain activity creates subjective inner experiences is a much bigger and thornier question about consciousness, one that will no doubt continue to be debated for a long time.