Synesthesia is a rare perceptual phenomenon in which the stimulation of one sensory modality, or exposure to one type of stimulus, leads to a sensory (or cognitive) experience in a different, non-stimulated modality. For instance, some synesthetes have colored hearing while others might taste shapes.
GRAPHEME-COLOR SYNESTHESIA is the condition in which individual printed letters are perceived in a specific, constant color. This occurs involuntarily and in the absence of colored font. It is the most common and widely-studied of all types of synesthesia (Mattingley, 2009). Many studies have suggested that the phenomenon is not due to associative learning, i.e. exposure to colored letters or blocks as a child (Rich et al., 2005). One neurological explanation is that it's due to greater white matter connectivity between the inferior temporal lobe regions that process letters and colors (Rouw & Scholte, 2007). 1
Learned Synesthesia
However, a new study has identified 11 synesthetes whose grapheme-color mappings appear to be based on the Fisher Price plastic letter set made between 1972-1990 (Witthoft & Winawer, 2013). 2 Letter-color mapping data were obtained from the participants using either The Synesthesia Battery Web site (synesthete.org) or in-house software. This required that the subjects use a color picker to identify the hue of 26 upper case letters and 10 numerals three times each (presented in random order). They did this in two separate sessions, and then the consistency within and across sessions was evaluated. The participants also completed a speeded Stroop-like task, where they had to identify whether the color font was congruent (A) or incongruent (A) relative to their synesthetic mapping.
Lo and behold, the resultant mappings were "startlingly similar" to the colors used in the Fisher Price toys from their childhoods! And 10 of the 11 participants reported owning the colorful plastic magnetic letters. In the figure below, the subjects are arranged left to right according to the number of matches with the Fisher Price set. S11 showed the fewest matches (n=14), yet the probability of obtaining 14 or more matches in 26 chances was estimated to be less than 1 in 1 billion...
Fig. 2 (modified from Witthoft & Winawer, 2013). Letter-color matching data from the 11 subjects. The diagram shows the color selected for each letter, averaged across three trials for each subject. The left-most column indicates the colors of the Fisher-Price refrigerator magnets used by all but 1 of the subjects as children.
Thus, the results provided clear evidence of a learned contribution to color-grapheme synesthesia, at least in this group of participants. But they don't negate a more purely perceptual version of the phenomenon in other synesthetes. The two synesthesiae can peacefully coexist:
Whereas some researchers have focused on genetic and perceptual aspects of synesthesia, our results indicate that a complete explanation of synesthesia must also incorporate a central role for learning and memory. We argue that these two positions can be reconciled by thinking of synesthesia as the automatic retrieval of highly specific mnemonic associations, in which perceptual contents are brought to mind in a manner akin to mental imagery or the perceptual-reinstatement effects found in memory studies.
Nonetheless, for some color-grapheme synesthetes, it's always a Red Letter A...
Footnotes
1 However, a newer study says it's more complicated than that (Hupé et al., 2012). These authors found that synesthetic letter experience did not activate color area V4, and that grapheme-color synesthetes did not show greater connectivity in the inferior temporal cortex:
At the end, careful reading of the relevant literature casts some doubt on the textbook story that synesthetes activate “color area V4” when viewing achromatic graphemes (but experiencing color) and on structural brain differences reported between synesthetes versus nonsynesthetes.2 Interestingly, Witthoft and Winawer cited a 19th century study that proposed the same thing (Calkins, 1893).
References
Mattingley JB. (2009). Attention, automaticity, and awareness in synesthesia. Ann NY Acad Sci. 1156:141-67.
Rich AN, Bradshaw JL, Mattingley JB. (2005). A systematic, large-scale study of synaesthesia: Implications for the role of early experience in lexical-colour associations. Cognition 98:53-84.
Rouw R, Scholte HS (2007). Increased structural connectivity in grapheme-color synesthesia. Nature Neuroscience 10:792-797.
Witthoft, N., & Winawer, J. (2013). Learning, Memory, and Synesthesia Psychological Science DOI: 10.1177/0956797612452573
It's a Red Letter A...
Letters A-Z, plus extra letters E, I, L, N, O, P, R, S, and T:
Perhaps the designer of Fisher Price fridge magnets was a synesthete.
ReplyDeleteExactly. Although it is fascinating, it doesn't negate the possibility that there is some almost universal (non-synesthetic/non-perceptual) set of associations between letters and colours all people share, and this is reflected by the makers. If there are countries with other colour/letter mappings for fisher price (or similar products) and it reproduces this finding, then the learned synesthesia explanation is most likely...
ReplyDeleteGood points Jon and Rogier -- got me thinking. However, if you look at the coloration of the Fisher-Price letters, they are just based on a repeating pattern of colors of the rainbow (without Indigo). It seems unlikely that any quasi-universal grapheme-color association would match perfectly to matchings between the order of the color spectrum and the arbitrary ordering of the alphabet.
ReplyDeleteI also wonder what colors letters are on kids TV shows like Sesame street. Do they show a red A, when they show A? also the common learning tool 'A is for Apple' probably shows a red apple. That could also impact it.
ReplyDelete@ John Plass
ReplyDeleteYeah, you're right. Obvious now you mention it!
@john Excellent point. My refutation refuted! Who said internet comments were useless?
ReplyDeleteRogier: Unlikely. The letters are colored in order of the rainbow, or if you will, in order of spectrum position. This is an obvious construction. If there was some universal association, you would expect the correlation to be randomly placed, but correlate with regard to shape or sound value. (So that for example T and K would be similar in color.)
ReplyDeleteThe more likely explanation is that the color order is indeed inspired by Fisher-Price, but that these individuals act like sponges for these types of references.
Isn't all vision 'learnt'?Infants can't make much sense of the visual feed and gradually gain abilities like depth perception and object identification. Cases where people who were blind from birth gain vision result in the person not being able to parse any information out of the 'noise'. But for us using the signal to make a coherent 3d model is not an associative process.
ReplyDeletenot so fast: what if the recurring Magic Number 7 is to blame, the letters, being chanted as a sequential set, is inherently divided in the same natural 7-set as the rainbow, and the rainbow, being a set ordered by nature (ie anstrom measures of increasing wavelength) is not just learned, but fundamental to our human vision? So there still could be a 'universal' map.
ReplyDeleteAlthough I grew up with abundant Fisher-Price letters on the fridge (and elsewhere), the way I see it is that (for instance) the B should be black & the G should be very dark blackish-green (that color isn't even IN the Fisher-Price set). Actually, I'm convinced the G should be blackish-green _unless_ it is either standing for the sound of J (in which case it should be puce, which is my opinion of what the J should be) or is standing for no consonant sound (as in "siGn") — in which case it should be clear. (The Fisher-Price set doesn't have puce or clear letters, either.)
ReplyDeleteIt also looks like in those cases where the color doesn't match the FP set, the next most likely is for it to be the direct opposite, like you'd get in an afterimage.
ReplyDeleteI just went over these with my synaesthetic 7 year-old who has had no previous exposure to the Fisher-Price letters. She disagreed with every single color-letter match except the red letter A.
ReplyDeleteI have synesthesia and they're all wrong for me as well--except the "A"--and my daughter has synesthesia, and we disagree about every nearly every color. We also both assign genders to colors, numbers, and letters, so we can argue endlessly about how wrong the other one is. For example, to me, O is an old woman, and is associated with white. To her, O is a man. You should hear us argue about the number 7...
ReplyDeleteAre there countries where common letter toys are colored differently where synesthesia trends can be checked?
ReplyDeleteEleven people do not make this a "trend". :-)
ReplyDeleteStill, this is a really significant result, if the synesthetes in the study are indeed genuine. (They most likely are, if they had to pass a Stroop test. The Stroop effect is totally involuntary.) It's interesting mainly for what it says about early learning.
I personally would love to know the origins of my colors (although I'm very glad they're not a boring Fischer-Price repeating rainbow, bleah!) I found a tantalizing hint in some Cuisenaire rods the other day, but only the first three rods matched my personal number-colors. So I'm both happy and sad for these eleven people.
At least it isn't anesthesia. Poor fellows....
ReplyDeleteSomeone with synthesis that is color/taste, can they only taste some colors, like purple taste bad but all other colors have no taste associated with them? Or do they taste all colors?
ReplyDeleteWhen Fisher-Price meets grapheme-colour synaesthesia that is a horrible thing indeed. I can't imagine what it must be like to have bad taste permanently encoded into one's brain. I so glad that my colours are more integresting ones.
ReplyDeleteI had this set too (I thought from 1969, but maybe not), so I wondered if that's where my synesthesia came from. But only three of the letters match. Anyone know what color the numbers were?
ReplyDeleteLaura A - Here's the Magnetic Number Board from 1979-1982.
ReplyDeleteOMG! I can't believe I found this! I knew precisely that this thing was what initiated my synesthesia! I'd love to contribute my current mapping.
ReplyDeleteSee also the Number Form article on Wikipedia, where the example of a number shape is just like a clock face:
ReplyDeletehttp://en.wikipedia.org/wiki/Number_form
That shape was probably learned.