A research team including Sakari Kallio have published an article in the International Journal of Clinical and Experimental Hypnosis entitled “Posthypnotic Suggestion Alters Conscious Color Perception in an Automatic Manner“.
Briefly, the study results indicate that a so-called “hypnotic virtuoso” (that is, a highly hypnotically suggestible individual) changed her response pattern to colored shapes in an objectively measurable way as a result of hypnotic suggestion. Importantly, this response pattern could not be mimicked by control participants or by the virtuoso herself, when not under the influence of hypnotic suggestion.