Smell sounds, see smells

Imagine that when you hear the note D-flat you envision sea blue. Perhaps you taste apples every time you listen to a word starting with the letter "S." Or maybe you feel a tingling in your arm whenever you see triangles. If you have ever experienced any of these uncanny phenomena, chances are that you may have a neurological condition known as synesthesia.

The department of experimental psychology and physiology at the University of Grenada recently began ground breaking research on the study of synesthesia and its relation to emotions.

Though this condition first garnered attention in the scientific community during the late 1800s, it was only recently that the phenomenon was embraced and researched extensively.

Professor Alicia Callejas Sevilla, who is carrying out the study, is covering various types of synesthesia, with a focus on the most widespread one, known as the grapheme-color form.

Synesthesia - from the Greek "syn," meaning "with," and "aisthesis," meaning "sensation" - is a phenomenon in which two senses are intertwined in such a way that the real information of one sense involuntarily activates a second subjective sense.

In other words, a sense, such as hearing, is perceived in tandem with an additional sense, such as sight.

In this case, musical stimuli, such as notes from a keyboard, elicit specific colors for each note.

In Calleja's case study, the grapheme-color type, individuals experience particular colors whenever they see or think of letters or numbers.

For example, "E" could be blue, "Y" could be green and "L" could be orange. The colors are reported by the synesthete as either real colors, or associations, in which the letters are not actually colored, but conjure an association of the color within the mind's eye of the synesthete.

The premise of Callejas' research is to study the emotional reactions of a person with consistent or inconsistent stimuli.

To illustrate this case, let's assume that a person indicates the letter "E" is blue. It is likely that if one ever sees the letter "E" written in red, this person may find this letter to be unpleasant and incorrect. A letter "E" written in blue, on the other hand, would be agreeable.

According to the Monitor on Psychology, a publication of the American Psychological Association, researchers believe that one in 2000 people are synesthetes, and up to 1 in 300 people may have some variation of the condition.

Some people have involuntary experiences with synesthesia, where it interferes with regular perception.

In a study done by University of Waterloo researchers Mike Dixon, Daniel Smilek, Cera Cudahy and Philip Merikle, when a patient was asked to solve simple arithmetic problems such as "5 + 2," he saw the color he associated with the number 7 instead of the number itself.

This finding suggests that the sensory areas of the brain have capacities that we may never be able to consciously grasp.

Synesthesia can occur between every combination of any two senses, such as flavors linked to words (lexical-gustatory synesthesia) and colors corresponding with sounds (sound-color synesthesia).

According to a 2006 study by Ward, Huckstep and Tsakanikos, there are a large number of core similarities between synesthetes.

Sound-color synesthetes see darker colors for lower sounds and vice versa for higher sounds.

In addition, grapheme-color synesthetes tend to share the same color for each letter. For instance, "O" tends to be white and "S" tends to be yellow.

Psychologist Daniel Smilek and his colleagues found that the more frequently letters or digits are used, the more luminous the synesthetic colors.

The development of the study of synesthesia for the past 20 years has been remarkable. Work within this topic is constantly increasing and the research field is consistently coming across new questions.

Undertaking these excursions into the unknown would have monumental ramifications for the fields of psychology, neuroscience and, as it had for artists like Vincent Van Gogh, the arts.