the r-squared values commonly found in psychology (.09 to .25). Explain that although these r-square's indicate that we fail to account for a great deal of the variability in human behavior, that's to be expected because (1) we have measurement error, and (2) we wouldn't expect a single variable (e.g., IQ) to account for all the variance in another variable (college performance).
Neurophysiologically, this pattern can be described by the wavelength-specific color receptor neurons of V4 being fused with the language processing neurons of the left middle temporal gyrus that are prone to perform semantic recognition. The characteristics of these two areas, such as frequency selectivity of V4, match the characteristics of synesthesia first discovered in this research: more frequent letters (interpreted in the LMTG) correspond with colors of longer wavelength (as are preferable in V4), corresponding with the letter frequencies of the native language of the synesthete.
Priming, greek/hebrew case study, mturk, biological methylation epigenetics
Synesthetic Associational Patterns between Letters and Colors
SYNESTHETICASSOCIATIONALPATTERNSBETWEEN LETTERSAND COLORSLaura Mariah Herman |Vision Sciences Lab, Department of Psychology, Harvard University, Cambridge, MAPine Crest School, Fort Lauderdale, FL
BACKGROUND• Synesthesia: inherent blending of the senses. – Grapheme-color is most common: letters/numbers→colors – Each synesthete associates each letter with different colors – Caused by excess neuronal connections per mutated enzyme – Single nucleotide polymorphism (16th chromosome)• Genetically transmitted to ~0.01% of population
Welcome to my worldof synesthesia!Welcome to my worldof synesthesia!
QUESTIONWhat causes certain letters to beassociated with certain colors? Why is this A red?
MATERIALS & METHODS• Color frequency (wavelengths) compared to letter frequency (%)• Synesthete color charts collective of synesthetes of the language (color the majority of synesthetes associated with each letter was used)• English: dictionary vs. Brown Corpus (better cross-section of English language) vs. children’s books (synesthetic associations form as the subject learns the alphabet and remain the same)• English, Spanish, German to verify causation vs. coincidence
DATA: FIGURES 3 AND 4 (SPANISH/GERMAN) Synesthetic Associational Pattern Between Frequencies in the Spanish r² = 0.47 Language 700Color wavelength (nm) 600 500 400 300 200 100 0 0.01 0.1 1 10 Frequency in the Spanish Language (%) Synesthetic Associational Pattern Between Frequencies in the German Language 700 Color wavelength (nm) 600 500 400 300 200 100 0 r² = 0.72 0.01 0.1 1 10 Frequency in the German Language (%)
DATA: FIGURE 5 (CHILDREN’S BOOKS) Synesthetic Associational Pattern Between Frequencies in Childrens Books R² = 0.5656 R² = 0.565 1000 Color Wavelength (nm) 100 0 2 4 6 8 10 12 14 Letter Frequency (%)
NEUROPHYSIOLOGICAL THEORY• From data, theorized which “color” and “letter” areas of the brain are fused in synesthetes• V4- color center in occipital lobe – Previously suggested by fMRIs of synesthetes – Columnar structure of neurons organized by long, middle, short wavelength cone signals as matches previous data – Neuron preference for more saturated colors as well as long-wavelength colors• Left Middle Temporal Gyrus (LMTG)- semantic processing/sensory integration – Lends itself to functional neuroconnections – Core component of individuality of semantic system• fusion of V4 and LMTG supported functionally and topographically
V4 and the LMTG. They are closely situated, as supports the theory of their connectivity in synesthetes.
DISCUSSION AND APPLICATIONS• First synesthetic color/letter association pattern found• Mapping of not only synesthetic connections, but also V4/LMTG (perhaps the largely uncharted LMTG is organized according to frequency of letters, etc.)• Induce (visual memory, artistic talent)/reduce (overwhelming colors for some synesthetes) synesthesia• Autism, schizophrenia, and epilepsy also caused by excess neuronal connections- synesthetes provide a model brain not inhibited by medication or cognitive impairments. – For example, sensory areas of the brain connected with the limbic system (anger management) in autistics, causing simple sensory cues to extremely anger the patient
BIBLIOGRAPHY Barnett, K. J., Finucane, C., Asher, J.E., Bargary, G., Corvin, A. P., Newell, F.N., Mitchell, K.J. (2007). Familial patternsand the origins of individual diﬀerences in synaesthesia. Cognition, 106, 871-893.Beeli, G., Esslen, M., Jancke, L. (2007). Frequency Correlates in Grapheme-Color Synesthesia. PsychologicalScience, 18-9: 788-792.Berlin, B., & Kay, P. (1969). Basic color terms: Their universality and evolution. Berkeley: University of California Press.Emrich, H., Schneider, U., Zedler, M. Welche Farbe hat der Montag? Berlin: S. Herzel Verlag, 2004.Kotake, Y. (2009). Organization of Color-Selective Neurons in Macaque Visual Area V4. Journal ofNeurophysiology, 102, 15-27.Nunn, J.A., Gregory, L.J., Brammer, M., Williams, S.C.R., Parslow, D.M., Morgan, M.J., Morris, R.G., Bullmore, E.T., Baron-Cohen, S., Gray, J.A. (2002) Functional magnetic resonance imaging of synesthesia: activation of V4/V8 by spokenwords. Natural Neuroscience, 4, 371-5.Rich, A.N., Bradshaw, J.L., Mattingley, J.B. (2004). A systematic, large-scale study of synaesthesia: implications for therole of early experience in lexical-colour associations. Cognition. 98, 53–84.Rissman, J. (2003). An Event-Related fMRI Investigation of Implicit Semantic Priming. Journal of CognitiveNeuroscience, 8, 1160-75.Scullion, Val., Treby, Marrion.,(2010). Creative Synaesthesia in E. T. A. Hoffmann’s Ritter Gluck. European Review. 18:239-262.Wei, Tao. (2012). Predicting Conceptual Processing Capacity from Spontaneous Neuronal Activity of the Left MiddleTemporal Gyrus. Journal of Neuroscience, 32, 481-9.Roland, D., Dick, F., & Elman, J. L. (2007). Frequency of basic English grammatical structures: A corpusanalysis. Journal of Memory and Language, 57(3), 348-379.