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We seem to be advancing rapidly on what can best be described (metaphorically), as the brain-function correlates of metaphor and analogy. Synaesthesia—mistaking sound for color, or perceiving numbers as having colors, etc.—may, in fact, be a characteristic of basic, inherent functions and structures, which are common in all brains. The determining factor may be only a question of degrees.
Take A One-Question Survey
One of the following alien-alphabet symbols is named “Woobul,” and the other one is named “kitkit.” Take your best guess to answer the question: which one is kitkit, and which one is woobul?
A
B
If you're like over 90% of respondents, you have guessed that 'A' is woobul and 'B' is KitKit. Why aren't the responses to this question around 50/50 for either symbol? According to Vilayanur Ramachandran, who used the above demonstration in his talk, what you are seeing in these responses is, in fact, the same mechanism that leads to synesthesia [1]. It is, obviously, a bit less pronounced in most people compared to those whom we would classify as having synesthesia.
I first saw Vilayanur Ramachandran discuss this theory about synesthesia in a TED talk linked on an entry at the neurdudes blog[2]. To me, what he is saying in this talk simply makes sense. His theory regarding the inter-relationships between different modes of stimulation nicely predicts the response to an informal survey he preforms on his audience. I've paraphrased that survey above (he uses Kikit and Buba) [3]. I think I know what your next concern might be. Don't worry, he gets it; that's not science. But it's a good reason to spend some time and do a little science, is it not? That is exactly what he and his team does. While he covered a variety of (equally cool) subjects for the TED talk linked at neurodudes, he more thoroughly describes his work on synesthesia in its own three part video talk (linked below).
Sharp Cheese
As stated, Dr. Ramachandran argues that the disorder may not be a disorder of how the brains of synesthete subjects are organized, but an attribute of how pronounced some normal brain structures (and their respective functions) are in some people relative to others. The underlying mechanism involved in synesthesia, says Dr. Ramachandran, is a normal characteristic of healthy brains. This is demonstrated dramatically in the above survey.
The above example demonstrates that you—and most other people—understand that the symbol that had the sharper, more abrupt shape was more closely related to the symbol whose pronunciation had the more abrupt sounds. This is because the underlying mechanisms that create synestheseia are the same mechanisms that enable us to make comparisons and connections between concepts across disparate sensory modalities, such as sounds and shapes. In similar fashion, you will understand what is meant when cheese (which is physically soft) is described as sharp. These are low-level metaphors, which we understand because our brains make these connections between various types of sensory stimuli.
Dr. Ramachandran further speculates (very convincingly) that these same mechanisms are what underlie our ability to use and understand analogy, simile, and metaphor. He posits that these differences form a continuum in the population, and explains that creative people, such as poets and artists, are eight times more likely to be synesthetes than are the rest of us.
Alternative Possibilities
In his talk (the one devoted to only synesthesia), Dr. Ramachandran carefully, and sagaciously, addresses concerns and possible objections that a lesser speaker may simply have dismissed outright. He reiterates the old stand-by psychological theory (the “simplest explanation,” on which those who mis-characterize Ockham's advice would insist) that the synesthetes are merely making it up, or are crazy.
In an attempt to eliminate this possibility and others, Dr. Ramachandran and his team asks: is this ability to see numbers as colors occurring closer to the sensory level, or at later more analytical processing levels in the brain? Dr. Ramachandran and his team developed a variety of experiments to answer this question. For example, he and his team developed a wonderfully clever experiment, in which a diagram of similar numbers was produced. People without synesthesia had a hard time picking out a small number of twos ('2') dispersed in a randomly spaced field of many fives ('5'). The synesthetes, on the other hand, immediately saw that the twos formed a triangle. They could do this because the twos were a different color than the five. They saw red twos (for example) forming a triangle on a background of green fives. So it is clearly a fairly low-level perception, and it made them better at picking out twos from a field of fives than the rest of us. Definitely not making it up, or crazy.
Where's Woobul?
Ok, so now Dr. Ramachandran takes some more pot-shots at his own results, saying that the above experiment convincingly establishes that synesthetes are not making it up, and that they're not crazy. It doesn't necessarily show that the effect is originating as a result of processes taking place at the lower-level (“earlier”) areas of the brain. That is, the above experiments don't necessarily show synesthesia as being something that occurs close to sensory processing stages in the brain (though the triangle-two experiment clearly supports that notion). He then describes how he and his team set out to answer this question with more certainty. If the phenomenon was facilitated at a higher, more abstract, processing-level, then a “IV” and a “4” would have the same color. Nope, the “IV” has no color. Not being satisfied with this, they further perform experiments in which the contrast of the displayed number is slowly reduced. As the contrast is reduced, the color fades, even though they can still see the number.
Interested?
This entry is merely a book report on Ramachandran's lectures on the subject, just to whet your appetite. Also discussed is that the color-number crossings exist in the fusiform gyrus area of the brain, producing “lower synesthetes.” The experiment related above, using 'IV' and '4', has also led to the discovery of higher-level synesthetes, having higher-level cross-connections. It turned out that there were some people who did see both fours as having the same color. They seemed to be crossing the numerical concept of four, rather than just the visual appearance of the number. The angular gyrus[note 4] seems to reside at the cross-roads for these phenomena at the higher, more conceptual levels—it is where concepts themselves are cross-connected, and it may be the germ of metaphor.
There's much more to tell, but of course, Professor Ramachandran can probably do a much better job of that than me. . He is a great speaker, btw.
Sources & Resources
Recent Vilayanur Ramachandran talk on synesthesia
In the following talk in three videos Vilayanur Ramachandran discusses his theory of the correlates and causes of synesthesia, and something he calls synesthesic metaphor.
[note 1] There are a variety of different (apparently valid) spellings, though it is becoming increasingly customary to spell it in the simpler form: “synesthesia” in countries with alphabets that are lacking the diphthong: æ. The simpler western spelling will be used in the remainder of this article.
[note 2] Some examples of other interesting subjects, which Dr. Ramachandran explored in that TED talk included: Capgras delusion, and mirror treatment for phantom limb syndrome
[note 3] Originally from the “kiki/bouba effect,” which was first discovered, studied, and documented by American psychologist Wolfgang Köhler in the late 1920s.
[note 4] Fusiform Gyrus is where “poly-modal convergence“ of information from closer to the sensory level is strongly thought to occur. It is a “crossroads“ where the lower-level perceptions get crossed, such as the visual appearance of a number. Angular Gyrus is where the concept represented by a number is processed, and where concepts (such as the concept of four) generally become intertwined with other concepts in “higher synesthetes.”
All the words a metaphor
And so too, it would seem, are our thoughts... Metaphoric intelligence and foreign language learning - Jeannette Littlemore "Metaphor is so pervasive in language that it would be impossible for a person to speak without using metaphor
Weblog: Loligo Blog Tracked: Jun 21, 15:31
Syntax not in Broca's Area?
There's an interesting article at the Talking Brains blog that gets our bearings and discusses our current understanding of the relationship between Broca's area and language. If you are still of the old notion, that it is the area singularly responsible
Dance and Sound
Remember the Moog synthesizer days? Just get the waveform and the attack/decay envelopes right and you could perfectly match the sound of any musical instrument. Not quite. Each instrument was played in a particular way by a human, and those particular
And so too, it would seem, are our thoughts... Metaphoric intelligence and foreign language learning - Jeannette Littlemore "Metaphor is so pervasive in language that it would be impossible for a person to speak without using metaphor
Tracked: Jun 21, 15:31
There's an interesting article at the Talking Brains blog that gets our bearings and discusses our current understanding of the relationship between Broca's area and language. If you are still of the old notion, that it is the area singularly responsible
Tracked: Aug 02, 02:46
Tracked: Aug 04, 09:10
Remember the Moog synthesizer days? Just get the waveform and the attack/decay envelopes right and you could perfectly match the sound of any musical instrument. Not quite. Each instrument was played in a particular way by a human, and those particular
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Tracked: Jan 06, 19:48