SYNESTHETIC

ASSOCIATIONAL

PATTERNS

BETWEEN LETTERS

AND COLORSLaura Mariah Herman |Vision Sciences Lab, Department of Psychology, Harvard University, Cambridge, MA

Pine 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 world

of synesthesia!

Welcome to my world

of synesthesia!

QUESTION

What causes certain letters to be

associated 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

SYNESTHETE COLOR CHARTS

0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 1 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0

0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0

0 0 1 0 0 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 1 0 1 0 0 0

0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 3 2 2 0 0 0 2 0 0 0 1 0 1 0 0 1 0 0 1 0 1 0 0

5 0 3 0 1 0 0 0 2 3 1 1 2 3 1 0 1 0 4 0 0 2 1 1 2 0

0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

0 0 1 0 1 3 0 1 0 0 2 0 0 0 0 1 1 0 0 0 0 1 1 2 1 1

0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 1

0 0 0 0 0 0 0 1 0 1 1 2 1 1 0 0 2 0 0 0 0 0 1 1 1 1

0 0 0 1 0 1 0 0 3 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 0 0 0 1

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0

0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0

0 1 0 0 3 0 0 0 0 0 0 0 3 0 0 2 0 0 1 0 0 0 0 0 0 0

5 2 1 0 1 0 1 1 0 0 1 0 2 2 0 3 0 0 1 0 1 0 0 0 0 1

0 0 1 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0

1 2 1 1 0 1 1 0 0 1 1 3 0 0 0 0 1 0 0 4 1 0 0 0 2 3

0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 3 0 0 1 0 1 1 0 0 0 0 0 0 0 3 1 0 0 0 0 0 1 1

0 3 0 0 0 0 1 0 0 1 1 0 1 0 2 3 0 3 0 0 0 2 1 0 0 2

0 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 1 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0

0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 2 1 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0

0 0 0 0 0 0 0 1 0 0 0 0 0 2 3 0 2 0 0 1 0 0 1 3 1 3

12 12 12 11 10 11 11 11 7 10 8 9 12 13 9 10 10 7 11 9 9 11 11 10 8 14

English

Spanish

German

DATA: FIGURE 1 (ENGLISH DICTIONARY)

R² = 0.659

300

0.1 1 10 100

Co

lor

wav

ele

ng

th (

nm

)

Frequency in the English Language (%)

Synesthetic Associational Pattern between Frequencies 1000

R2= 0.6597

DATA: FIGURE 2 (BROWN CORPUS)

R2= 0.45299

DATA: FIGURES 3 AND 4 (SPANISH/GERMAN)

0

100

200

300

400

500

600

700

0.01 0.1 1 10

Co

lor

wav

ele

ng

th (

nm

)

Frequency in the Spanish Language (%)

Synesthetic Associational Pattern Between Frequencies in the Spanish

Language

0

100

200

300

400

500

600

700

0.01 0.1 1 10

Co

lor

wav

ele

ng

th (

nm

)

Frequency in the German Language (%)

Synesthetic Associational Pattern Between Frequencies in the German

Language

r² = 0.47

r² = 0.72

DATA: FIGURE 5 (CHILDREN’S BOOKS)

R² = 0.565

100

1000

0 2 4 6 8 10 12 14

Co

lor

Wav

ele

ng

th (

nm

)

Letter Frequency (%)

Synesthetic Associational Pattern Between Frequencies in Children's Books R² = 0.5656

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 and 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

BIBLIOGRAPHYBarnett, K. J., Finucane, C., Asher, J.E., Bargary, G., Corvin, A. P., Newell, F.N., Mitchell, K.J. (2007). Familial patterns and the origins of individual differences in synaesthesia. Cognition, 106, 871-893.

Beeli, G., Esslen, M., Jancke, L. (2007). Frequency Correlates in Grapheme-Color Synesthesia. Psychological Science, 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 of Neurophysiology, 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 spoken words. Natural Neuroscience, 4, 371-5.

Rich, A.N., Bradshaw, J.L., Mattingley, J.B. (2004). A systematic, large-scale study of synaesthesia: implications for the role 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 Cognitive Neuroscience, 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 Middle Temporal Gyrus. Journal of Neuroscience, 32, 481-9.

Roland, D., Dick, F., & Elman, J. L. (2007). Frequency of basic English grammatical structures: A corpus analysis. Journal of Memory and Language, 57(3), 348-379.

THANK YOU FOR

YOUR TIME AND

CONSIDERATION!