To form a sound into a physical shape? To taste musical intervals? To see music as a colored haze? These descriptions are not the result of a vivid imagination, but the way people like Elisabeth Sulser perceive the world of music: As an expression of colors, shapes or flavors.

This rare neurological phenomena of a so called double perception is also known as synesthesia. Merely one percent of the population has the ability to combine different sensual perceptions like sounds or colors simultaneously as described above. Certain brain structures of the people concerned are linked more particular and intense then usual. Due to this fact these specific perceptions occur involuntary and cannot be suppressed.

It was at the age of sixteen that Elisabeth Sulser became aware of her synesthetic perceptions. Ever since she participated as a test person in several studies, among others in one of the Institute of Neuropsychology at the University of Zurich. Her specific version of synesthesia has been pointed out frequently in the international media, for her being the only person worldwide so far to be declared a synesthete with a interval-taste combination.

The term comes from the Ancient Greek words for «joined sensation». It describes the simultaneous experience of multiple sensations, caused by the sympathetic excitation of a single sense organ. The reason for this neurological phenomena is a stronger connection then usual between two or more areas of perception within the human brain.

The most common occurrences are visual synesthesias. It means that visual perceptions are triggered by acoustical impressions like sounds or words. It can also signify that emotions can be triggered by visual perceptions or acoustical impressions. Over sixty versions of synesthesias are known to date, although not all of them need to be triggered by a sensory stimulus. For example many synesthetes perceive numbers as colors. But some of them may already experience a color only by visualizing a number.

Bohemian Rhapsody, Queen

There are also many non-visual combinations of perceptions, like smells, tastes or the sensation of a touch. Elisabeth Sulser is one of them. While participating as a test subject in a neuropsychological research project at the University of Zurich between 2004 and 2005, she was «discovered» to be the bearer of a very rare form of synesthesia. It manifests in two forms simultaneously. On the one hand Elisabeth Sulser sees colors while hearing music or sounds (for example red for the note C, yellow for D or blue for G). She then projects these colors on an «imaginary canvas» and thus creates a painting that constantly changes its form like a kaleidoscope. The colors shift their form and adapt to the tempo and the figure of the music.

On the other hand Elisabeth Sulser combines intervals with tastes – so far a unique combination worldwide. While hearing an interval of two tones within an octave she senses a taste on her tongue. A small second tastes sour, a big one bitter, a mall third tastes salty, a big one sweet, the quint like a glass of water, a small sixth like cream, a big one like skimmed cream, a small seventh bitter like the big second – and the big seventh tastes sour like the small second.