Synaesthesia

A subjective sensation of one sense being stimulated by another, synaesthesia is a non-debilitating perceptual disorder, which means literally joined sensation. Derived from the Greek words "syn" meaning join and "aesthesis" meaning perception or to perceive, it is a word used to describe the involuntary physical experience of cross modal association. In other words, the stimulation of one sensory modality reliably causing a perception in one or more different senses. For example, a synaesthete may see coloured shapes projected into their field of vision as a result of auditory stimulation.Types of SynaesthesiaThere are many different types of syaesthesia.

In fact, the crossing over of two or more of the senses means there can be 31 possibilities of different combinations of the senses.It is divided into 2 categories:Two Sensory SynaesthesiaThis is when stimulation of one modality triggers the perception in another modality in the absence of direct stimulation to this modality, (the crossing over of two sensory modalities), usually unidirectional. eg. A certain word produces a sensation of colour, or they can be bi-directional, eg.

Not only is the latter true but also a colour can produce the sensation of sound. Some examples of two sensory synaesthesia are:Coloured Hearing - where sound evokes a sensation of colour. It has been recorded that an opera is like experiencing a painting. Sometimes each musical instrument has its own colour.

An example of bi-directional in this type of synaesthesia would be where the changing of a traffic light evoked a bell like sound.Coloured Olfaction - where smell evokes the sensation of colour. For example the smell of garlic may be perceived as a blaze of orange.Coloured Gustation - where taste evokes the perception of colour. Something salty may be experienced as red, something sweet as bluish/purple.

Tactile Gustation - where the taste of something is experienced as shape. Grapefruit may be a twisted triangle, other citrus fruits may have similar triangular qualities - an orange may be an equilateral triangle.Multiple Sensory SynaesthesiaThis is when three or more of the senses are crossed, and contains the most common form of synaesthesia. Some examples of this type of synaesthesia are:Coloured Numbers - the experience of numbers that have their own colour. eg.

1 could be black, 2 could be yellow, 5 could be blackish grey, 8 could be bluish, 9 reddish brown and so on. The experience of date has its own specific colour combination. ie. If discussing events that happened in the 18th century, this information would be visualised on a bluish/black background, if the synaesthete experienced these colours for these numbers.Coloured Letters - the experience of letters as colours. Sometimes only vowels are coloured and poets with this perception often use it when composing.

Other times each letter has its own specific colour.Coloured Graphemes - the experience of colours when a person hears words. When a person speaks, a synaesthete with this perception will experience the words as a blend of colours.Shaped Numbers - the experience of numbers as shapes. When a person hears or reads a number the synaesthete will experience it as a shape, like a circle or square, etc.There is also what is known as "Pseudosynaesthesia" which anyone can experience with consumption of the right combination of illegal substances.

Although, this can also occur as a result of what is known as "learned association".What Causes SynaesthesiaAlthough not yet fully understood and until recently considered to be amusing yet unimportant, there have been a few different claims on what causes synaesthesia. Dr. Simon Baron-Cohen of Charring Cross Hospital in London says that our brain processes sound and vision in entirely different areas, called modules. He suggests that with synaesthesia, these modules are connected by exaggerated neural connections, and therefore causing confusion between the senses.

As opposed to Dr. Richard Cytowic, a neurologist in Washington DC, who says that the limbic system of our brain deals with emotion and memory and that it exerts a very profound influence both on how we think and act. He says that in this system there is a kind of "togetherness" of all our senses and that we are all really synaesthete's but only a handful of us are consciously aware of it, (taken from "Horizon - Orange Sherbet Kisses, Synaesthesia).Diagnostic FeaturesAs defined by Dr. Cytowic, there are 5 main diagnostic features of synaesthesia:1.

Involuntary - The sensations cannot be suppressed or incurred though the intensity is influenced by the situation in which they occur.2. Projected - The sensations are projected into the environment: it is not just heard in the person's head but the person actually sees a sound or hears a picture, etc.3. Durable and Generic - Experiences do not change over time. If you see red when you hear a bell, you will always see red when you hear a bell.

4. Memorable - The experiences are often the aspect of something that is remembered best. For example, it may be easier to remember that a person's name is yellow than the name, although the colour would help to recall the name.5. Emotional - Having these experiences causes ecstasy and is viewed as an accomplishment.Who Has ItAs it is difficult to carry out accurate tests, it is thought that we are all born synaesthete's.

A newborn's senses are said to be all intermingled and connected but by the age of about three our senses have usually separated and we forget the experiences. As we are reminded by Charles and Daphne Maurer in The World of the Newborn, (Dianne Ackerman in "A Natural History Of The Senses", Phoenix 1996, page 289):His world smells to him as much as our world smells to us, but he does not perceive odours as coming through his nose alone. He hears odours, and sees odours, and feels them too. His world is a m�l�e of pungent aromas - and pungent sounds, and bitter smelling sounds, and sweet smelling sights, and sour smelling pressures against the skin.

If we could visit the world of the newborn, we would think ourselves inside a hallucinogenic perfumery.Currently it is estimated that around 1 in 200 people have synaesthesia but this will depend upon whom you ask. Dr. Baron-Cohen et al (1996) placed an ad in a newspaper and received just 28 replies - they concluded that it's around 1 in 2000. However this is considered to be an underestimate because not all synaesthete's will have seen the advert, or some may have just not replied, (www.psychol.

ucl.ac.uk/jamie.ward/qanda.

htm). Studies carried out in the U.S. show that three times as many women as men have synaesthesia whereas studies carried out in the U.K. show that eight times as many women are affected.

History of Synaesthesia"Although medicine has known about synaesthesia for three centuries, it keeps forgetting that it knows,"--Dr. Richard Cytowic, in "Synaesthesia: Phenomenology and Neuropsychology - a review of current knowledge."Pythagoras, a Greek philosopher who lived between 569 BC and 475 BC, was probably the first person to ever write about synaesthesia, (www.wam.umd.edu/~mjhickey/stieglitz/synaesthesia.

htm). However, the first modern scientist to write on synaesthesia was Sir Isaac Newton, in 1704, when he noticed a parallel between colours of the spectrum and the notes of a musical scale. L.B. Castel, a Jesuit, also noticed this relationship and in 1735 he built what is thought to be the worlds first colour organ. With a few other references in the 1700's and a few more in the 1800's, the 1900's really saw an explosion in literature dedicated to understanding or recounting synaesthesia.

An interesting event occurred in 1944, when there was an attempt to teach coloured hearing to those who did not naturally possess the skill. Despite the numerous accounts of synaesthesia, the scientific community has attributed synaesthesia to everything from "illusion" to a "crossing of wires in the head." At times it was even thought that people who claimed to have synaesthetic experiences were simply schizophrenic.Living With SynaesthesiaTo understand why, or how many, people experience synaesthesia is one thing, but in order to really understand it, it is necessary to see the experiences of people who have it.

There are a number of generalized trends in people with synaesthesia, but these are generalized and do not apply to all synaesthete's:* They prefer order, neatness, symmetry and balance.* They are more prone to unusual experiences such as d�j� vu, clairvoyance, precognitive dreams and the feeling of a presence.* More synaesthete's than non-synaesthete's have right-left hand confusion.* Mathematical abilities and spatial navigation are below average.A fairly common experience of people with synaesthesia is that they cannot concentrate on talking to some people because their voice hurts, or sends flashes of colour that disrupts them.

Or the voice could be so intriguing that the sensations produced by the voice distract you from concentrating on what is being said and meant. It can be seen as wonderful because everyday experiences can be so much more intense and emotional but it could also be possible for it to get in the way. Despite the fact that synaesthetic experience can get in the way, they can be useful too. On average, syaesthetes score significantly higher than other people in memory tests.This may be due to the various associations the word has in the different senses.

In general, the success rate of memorization increases when you use more than one sense to learn. Also, association with something else often helps to remember. Syneasthetes do this naturally, without trying. A.

R. Luria, in a book called The Mind of a Mnemonist, wrote of a man referred to as Mr. S. who had synaesthesia to a greater degree than is common, having associations between four senses, thus representing an extreme case. He describes his ability to remember words:"..

.I recognize a word not only by the images it evokes but by a whole complex of feelings that image arouses. It's hard to express..

.it's not a matter of vision or hearing but some over-all sense I get. Usually I experience a word's taste and weight, and I don't often have to make an effort to remember it - the word seems to remember itself."