Instead, current research is interested in the correlation between synesthesia and left-handedness, since left-handedness is known to be associated with other unusual "cross-wiring" in the brain (the "right" or creative side of the brain is more dominant). Brain imaging proves the cross-linking concept in that for someone with visual-gustatory synesthesia, the taste center of the brain will be activated along with the visual centers (visual cerebral cortex) when a person is given a visual cue (Roeckelein, 2004). Synesthesia is also thought to involve anomalies in the brain's limbic system, which not only controls the coordination of senses, but some information-processing activities as well (Roeckelein, 2004; Phillips, 2010). In addition, some researchers believe that everyone is born with "cross-wiring," but this wiring is refined and "corrected" with experience (Phillips, 2010). Finally, in a 2009 study, researchers found evidence to suggest that synesthetic experiences are "driven by late, perceptual processing, rather than early, unisensory processing"; this finding supports the hypothesis that synesthesia is related to activity in the brains' information-processing and sense-processing limbic system (Bargary & al, 2009). Ramifications

The study of synesthesia could shed light on many neurological functions not yet completely understood, such as left-handedness, differences in male and female brains, and the roots of creativity. In fact, many people known to have had synesthesia were highly creative -- composers, poets, or authors. Synesthesia is also being studied for what it may reveal about human consciousness (Phillips, 2010). For example, particularly in light of the recent finding that suggests synesthesia is the result of higher-level processing, researchers may finally be able to solve the mystery of the "binding problem" (Bargary & al,...

The "binding problem" refers to how the brain puts together all of its sensory perceptions into one whole experience, such as determining that a dog is a dog (Phillips, 2010). This area of study could also have implications for the burgeoning field of artificial intelligence, which seeks to understand how man can be so superior to machine when it comes to certain types of information processing.
In addition, advertisers are interested in phenomena related to synesthesia, such as how to invoke certain emotional reactions in consumers with specific sights, sounds, etc. (Nelson & Hitchon, 1999). This type of synesthesia, common to everyone, is known as "metaphorical synesthesia" (Nelson & Hitchon, 1999). One 1999 study found that "cross-sensory ads are perceived to be pleasanter and more novel than literal ads," and "cross-sensory ads were preferred over literal ads when subjects were asked to select the better ad" (Nelson & Hitchon, 1999). This makes sense in that the cross-sensory ad should be more stimulating overall, but the psychological implications warrant further research. For instance, what personality types most prefer the synesthetic ad?

References

Bargary, G., & al, e. (2009). Colored-Speech Synaesthesia Is Triggered by Multisensory, Not Unisensory Perception. Psychological Science, 3 (2), 1-5.

Birren, F. (1961). Color Psychology and Color Therapy: A Factual Study of the Influence of Color on Human Life. New Hyde Park, NY: University Books.

Harriman, P. (1946). Twentieth Century Psychology: Recent Developments in Psychology. New York: Philosophical Library.

Nelson, M., & Hitchon, J. (1999). Loud Tastes, Colored Fragrances, and Scented Sounds: How and When to Mix the Senses in Persuasive Communications. Journalism and Mass Communication Quarterly,…