My blue is your blue: different people's brains process colours in the same way

"Is the colour you see the same as what I see? It's a question that has puzzled both philosophers and neuroscientists for decades, but has proved notoriously difficult to answer. Now, a study that recorded patterns of brain activity in 15 participants suggests that colours are represented and processed in the same way in the brains of different people. The findings were published in the Journal of Neuroscience on 8 September."

"The pair used functional magnetic resonance imaging (fMRI) to compare activity in the brains of a group of participants while they viewed different colours. This allowed them to create a map of brain activity that showed how each hue was represented neurologically. They then trained a machine learning model called a linear classifier on this data, and used it to predict which colours were being viewed by members of a second group of study participants, on the basis of their brain activity."

Fifteen participants had brain activity recorded while viewing different colours. Functional magnetic resonance imaging measured activity in visual brain regions across hues. Patterns of activation were mapped to show how each hue was represented neurologically. A linear classifier trained on one group's neural maps predicted viewed colours for a second group based solely on brain activity. Classification success indicates that colour activates similar neural patterns across different individuals. Similar low-level representations across brains enable cross-subject decoding of perceived colour. The neural maps and classifier performance support the existence of consistent, shared colour coding in human visual cortex. Results imply that perceptual experience of colour may rely on common neural encoding across people.

Read at Nature