If I told you that the letter “G” is red, you might be confused. But if you had what’s called grapheme-color synesthesia (GC), chances are you’d argue I’m wrong. That’s because many people who experience this phenomenon think that “G” is green. Grapheme-color synesthesia is one of the most common types. So is chromesthesia, the association of colors with sounds, which allows people to experience music as color. There are also weirder and wilder forms: some people experience tastes related to certain words, while certain synesthetes attribute things odd or even.
Although people have known about synesthesia for centuries, there is still a lot we don’t understand. We know that GC synesthetes make effortless, automatic, and consistent connections between letters and colors, but researchers are still exploring what might influence both the condition and the exact associations people make. But some recent results suggest a potential contributor: refrigerator magnets.
A recent article in PLOS ONE suggests that the letter-color combinations of many GC synesthetes may have been determined by objects in their environment as children, such as colorful alphabet fridge magnets. The researchers are clear that they are not suggesting that synesthesia can be learned, or that colorful letter toys lead to synesthesia. Rather, their results simply show that the associations can be influenced by their environment. Knowing this may shed light on some of the mysteries surrounding the condition.
The data comes from the Synesthesia Battery, a site where people suspected of having synesthesia can research their condition in exchange for providing research data. The tests on the site verify whether participants are synesthetic by checking whether their letter color matches are consistent and whether they take longer to process letters that are not in the “correct” color.
Using data from 6,588 people, the researchers determined which colors were most associated with which letters. They found that their results were consistent with previous experiments that showed that English speakers often have possible associations based on spelling. For example, “G” is usually green, while “Y” is usually yellow – tendencies reflected in the trends present in large collections of synesthetes.
These results were then compared to the colors of a specific refrigerator magnet set, a Fisher-Price set produced between 1971 and 1990. The group of participants was limited to those born after 1967. (5.9 percent) had more than 10 letter color associations that matched the magnet set. For those born after 1971, this share rose to 9.1 percent, and for those born between 1975 and 1980, it rose to 15 percent.
In comparison, the total population was more consistent with the general associations found in the full sample of 6,588 people. Nearly half of all GC synesthetes, with birth dates ranging from 1940 to 2000, had more than seven matches to the more common pattern (such as the “G” for the green example above). “Whatever the motivation [general] matching behavior in the data set is present continuously, while the proportion of magnet synesthetes rises and falls with the availability of the magnet set,” the authors write. When the “magnet” synesthetes had some associations that did not match the magnet set, they generally fell in line with the overall pattern.
What’s important to remember is that these are just the cases we can trace, the authors note. This was a particularly popular toy that was available for a period of time – for other synesthetes there may be more obscure influences, such as a particular alphabet poster in a kindergarten classroom. Each individual may also have associations influenced by specific toys or other factors. And of course there are also the cultural influences such as the linguistic cues that lead to a common association between “B” and “blue”.
What this tells us is that GC synesthesia can, at least sometimes, be shaped by environmental factors. This finding does not contradict data showing that synesthesia is linked to genetic predisposition, the authors write, but it does align with other evidence suggesting that learning plays a role in certain forms of synesthesia. That seems to be true for most synesthesia that involves some kind of cultural order, such as days or the week or numbers; other types of synesthesia, such as chromesthesia, may not work in the same way.
A question raised by this finding is whether the designer of the magnet set was a GC synesthete, and whether this means that synesthetic associations can be culturally transmitted. There is also more work to be done to establish the exact link between synesthesia and associative learning, to find out why some, but not all, associative learning is associated with synesthesia.
PLOS ONE2015. DOI: 10.1371/journal.pone.0118996 (About DOIs).