yellow vase yellow vase yellow vase yellow vase yellow vase ...

One of those things which amused me during class, was to take two words (I liked "yellow vase") and reiterate it over and over in my head. If you do this at least twenty times, then you'll start feeling that you lose the meaning of the words, and start wondering about the odd sequence of letters. Using your own name works, too, and it works best when doing it aloud (although for evident reasons not recommended in school). Blogger Phil from Philosophistry even called it in 2009 a "fun experiment".

And experiment it is indeed... it is science and even has a cool scientific name: Semantic Satiation. Try repeating that twenty times ... The term, according to Wikipedia, was coined by L James in 1962, and since then an extensive corpus of studies has been written that describe the phenomenon. For instance, this study from 1990 by Smith and Klein indicates that, in a word matching experiment, the effect lasted even when words in the task were accompanied with related words from the same group as the repeated word. Even though the phenomenon is about subjective loss of meaning, there is a degraded performance that is measured, and shows that it is a real effect. Last year, a study by Mulligan and Petersonshowed that the effect even lasts for a couple of days.

Of course several researches startedanalyzingthe effect with EEG (Electroencephalography), better known as "chewing gum on your head". Resultsfrom Kunios et al.confirm graphically what one could expect from the descriptions above: non-satiated words had a bigger effect on the brain signaling than satiated words, indicating some sort of "fatigue". This study is interesting, because it also shows how one reacts through the first second after presentation of the target word, and how the results differed also in left and right hemispheres (satiated words were more active in the left side).

What is the cause? The fun part is, we don't know yet (so still plenty of things to discover). And yes, I really mean "fun", because it means there is still a lot of things to discover. The EEG study to which I referred seems to indicate it is not related to perceptual or sensory adaptation, but related to how meaning is constructed in our brain. This semantic processing seems impaired by the repeating of the words, but the results are not entirely conclusive. Another study, by Antropus and Duff,showed that the effect disappeared when the words were repeated by different voices, indicating that some sensory processing still is involved somehow. I think it is safe to say that the jury is still out on this, and that more research should be done.

As usual, I love it when there are plenty of things to discover in science, and that we don't know yet definitely how it works. That's how science works, and it's nice to see it working in practice. This also means that in a couple of years, I might have to do a follow-up blog post, too.In the mean time, don't hesitate to practice at home ...

Note: want to know a lot (really, a lot) more about semantic satiation? Search for those words on Google Scholar, and be ready to pass several hours going through some of the articles referenced there. Google Scholar should be one of your first stops in looking for science articles. One disadvantage, you need to know the term real scientists use to have good search results.