Psychedelics are a class of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness.

The authors of the 2017 online research survey believe that the improved symptoms of color-blindness in individuals who experienced “new colors” originates from associations between “pre-existing concepts of colors” (yellow, for example, which is commonly associated with the adjectives “shiny and happy”) and the “alien photisms” derived from a more expanded and varied higher processing of colors. Probably, the altered processing steps of the signals related to the colors transmitted through the optical nerve might be linked to the well-known and studied neuroplasticity psychedelics trigger in their target areas in the brain.

In summary, the ability to see new colors conferred by psychedelics in color-blinded individuals could be the result of linguistic pre-associations of the unseen colors, merged with the visual hallucinations (the “photisms”) psychedelics produce at the level of synapses and networks, thanks to enhanced communication between different regions of the cortex promoted by psychedelics.