I got a lot of comments on my previous post on synthesia, so it seems there’s some interest there.  Check out this post on Cognitive Daily about a study of the rarest form of synthesia – tasting words.

For more common (or rather, less uncommon) forms of synesthesia, the most convincing evidence that it’s real comes from studies showing that synesthetic associations are stable. If “A” is associated with the color blue now, it will still be associated with blue six months from now. What’s more, sometimes the letter-color associations are the same for different people. With only one example to study, this type of evidence is harder to come by, but at least Gendel could test TD at different times and see if her associations were stable.

Gendel presented TD with 806 randomly selected words, and 222 nonsense words created from English-language sounds. She was asked to write down what taste (if any) she associated with each word, and rate the strength of the association. Then the test was repeated three months later. Almost 50 percent of the time, TD experienced a taste sensation accompanying the word. In those cases, 88 percent of the time that sensation was identical or nearly identical three months later. Stronger taste sensations were significantly more likely to be repeated at the end of the study.

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tt_icon_170This week’s episode of my Science Teaching Tips podcast actually features, well, me! Yay. It’s nice to record myself, not always other people, though the folks at the Exploratorium are so darned clever and fun, I feel it’s my mission to document every last scrap of their wisdom and energy. I’m trying…

So, this time I give you a way to adapt a great Exploratorium exhibit to something you can do at home with a friend and a set of keys.  It’s about how we localize sound, which is something very important for people who use sound to navigate (like blind people).  So, find out more about the perception of sound by listening in to this week’s episode.  For those of you who haven’t listened before, these are just 5 minutes long!

Listen to Find that Sound.

Edmund E. Kasaitis.

Photo credit: The full moon rising over Manchester, Maryland. Credit: Edmund E. Kasaitis.

I went hiking under the full moon last night, without even knowing that it was something special (other than a beautiful big pink full moon over the lights of Boulder). Last night was the solstice moon, as one of my fellow hikers tried to inform me. I say “try” because he was struggling to explain why it was that the moon looked abnormally large last night. It turns out that it’s just an exaggerated moon illusion. The moon illusion refers to the fact that the moon looks much larger at the horizon than it does overhead.

Back when I was studying psychology (gosh, in the early 1990’s, I feel *old*) the accepted explanation was that it was due to the Ponzo effect. That refers to the fact that we know that if something is far away, but still looks big, it must be *really* big. Like, if you see an ant lumbering on the horizon, but your depth cues tell you the ant is about a mile away, but it still looks big to you? Time to run, you’re in a bad B movie.

And when the moon is on the horizon, we have a lot of depth cues (like trees and such) that tell our brain the moon is really far away. And so since it still looks pretty big, our brains conclude that it must be really REALLY big — like the ant Godzilla above. And when the moon is overhead, there’s nothing to tell us that it’s far away, so we assume that (for its size) it’s just a puny regular sized moon.

But there’s a problem with that, since airline pilots still see the moon illusion when all they can see around them is clouds. Some people played around with atmospheric effects (there’s more atmosphere between you and the moon when you’re looking across the earth at the horizon instead of straight up into space) but that doesn’t explain it.

The more recent explanation, which I kind of like, says that we actually have different conceptions of the horizon versus the sky overhead. We think of the horizon as far away (as far as the eye can see!) and the sky overhead as being just about as tall as the clouds. So, it’s not so much that the depth cues at the horizon tell us that the moon is far away, but that we just have this erroneous impression that the sky overhead is really close by.

It’s amazing the ways our eyes and brains can trick us. That’s why it’s important to recognize how our perceptual systems work when trying to understand what we see, especially when trying to evaluate what seem like outlandish scientific claims (like faces on mars for example!)

Photo credit: The full moon rising over Manchester, Maryland. Credit: Edmund E. Kasaitis.

I’ve always been sort of fascinated by synthesia. A brain with a predilection to mix colors and letters and days and feelings and smells sounds kinda trippy. I’ve always thought (and I think I may have read somewhere) that it seems like a very rich way to experience life. I mean, confusion is orange? I don’t even have a way to relate to what that means, except through certain experiences from my college days. A recent web article writes about synthesia and some current theories (they still don’t really know what causes it). One interesting theory

All of us are able to perceive the world as a unified whole because there is a complex interaction between the senses in the brain, the thinking goes. Ordinarily, these interconnections are not explicitly experienced, but in the brains of synesthetes, “those connections are ‘unmasked’ and can enter conscious awareness,” said Megan Steven, a neuroscientist at Beth Israel Deaconess Medical Center.

Because this unmasking theory relies on neural connections everyone has, it may explain why certain drugs, like LSD or mescaline, can induce synesthesia in some individuals.

One thing I’m curious about is how different (and how similar) the experiences of different “synthetes” is. The article mentions this a little bit. For example, a lot of synthetes associate colors with letters. But for some, they see the color in their minds’ eye. Others see the color sort of painted onto the physical letter. One synthete responded via a comment to the article above that the colors he sees associated with letters are completely different from those for others.

One synthete writes:

Not only do the colors vary from person to person, but the associations too. I see not only colors for letters and numbers, but gender too, which isn’t something I’ve seen discussed in articles like these. The letter “A” is not only red for me, but also very strongly female. Also, I see the year as a kind of pie chart around me (its orientation is synchronous), and numbers, especially the first 10 integers, have a very particular spacial position.

And another replies:

For me the colour is only the start – there’s a whole complex series of moods and associations that follow on from the first ‘hit’ of colour. This is particularly strong with peoples names.
An additional observation – often the colour of the word id bizarrely out of whack with the real colour of the object. So, for me, ‘tree’ has no trace of green or brown or any other ‘tree’ colour – it’s a soft grey, fading to creamy yellow at the end.

Interesting stuff, but hard (though not impossible) to study, being based on subjective experience.