For whatever reason, at some point or another, you may have decided to say the same word over and over again. It might have been the word strange. That’s strange. Strange. Sssttt-Rrraaa-Nnn-Ggg-Eee. After repeating the word a few times it started to lose it’s meaning. Experientially, it just became an abstract sound.
While this may have felt like a sort of cognitive processing glitch, some scientists, such as cognitive neuroscientist David Huber from the University of Massachusetts, believe this experience gives us an important insight into how our minds perceive the external world.
Psychologists have been aware of this bizarre effect since way back in 1907, when it was first described by The American Journal of Psychology. However, it took until the 1960’s before someone decided to study it seriously. Leon James, a professor of psychology at the University of Hawaii, made it the subject of his doctoral thesis, coining the term semantic satiation.
Put simply, sensory signals trigger the firing of regions in the brain that are linked to concepts and categories that give those signals meaning. The sound of a word is one such signal. After firing once it takes more energy to fire those brain cells a second time. So when we hear a word the second time around, it is more energy intensive for the brain to continually link it to the concepts associated with the word. It takes even more energy a third time. A fourth time, and maybe those cells won’t even fire. James called this reactive inhibition.
The more you are exposed to a set of stimuli, the more resilient to the stimuli you become. This phenomenon is illustrated in what is a now famous study: Researchers played a loud tone to a sleeping cat, and the cat was up and alert immediately. The researchers continued to play the loud tone once the cat had fallen asleep, again and again, and each time the cat’s reaction was a little more subdued, until it eventually hardly reacted at all. But when the researchers altered the tone, only slightly, the cat reacted like it was hearing it for the first time again.
For humans, no word is immune from semantic satiation, but it may take longer for different words to lose their meaning depending on the emotional strength of your concepts of said word. For example, you may have more potent imagery tied to a word like "hospital" compared to a word like "lamp." Because of your previous experiences in hospitals, and the associated connotations of the word, your mind cycles through meaningful categories that are linked to the word hospital, making it harder to reach a point of detachment. Whereas the word lamp has less meaningful implications. (That is, unless you have had a traumatic lamp-related incident.) The dissociative effects of semantic satiation have also been studied in the treatment of phobias and speech anxiety.
Been There, Done That
Huber has been investigating semantic satiation, or what is now known more generally in academic circles as associative satiation, for a few years now. He thinks there is something similar going on when words lose meaning through repetition and when our brains disregard freshly-processed information about our environment.
Neural habituation, a process studied by Huber, is the reduction of our cognitive processing capacities in relation to things we have already experienced. From a neurological point of view, we don’t need to waste valuable resources interpreting information from our senses when it's already been processed before. Habituation helps our brains reduce the amount of interference from things that we have already seen, enhancing our perception of novel information.
In the same way, if a word is being used to retrieve a certain meaning repeatedly, it’s less energy intensive for your brain to drop the meaning and let the word exist as a sound, as opposed to continually dredging up all of the context and meaning you associate with the word every time you say it. It’s kind of like The Boy Who Cried Wolf, except you're the boy yelling "wolf" repeatedly, and your brain is the town's people who eventually ignore you.
Huber was part of a study that found support for this idea, where a semantic satiation effect occurred when participants were asked to perform a speed matching task. Participants were given repeated cues of category labels like ‘fruit’, and were asked to name something that belonged to that category like ‘apple’. After a while, participants' responses slowed if the category repeated itself. However, participants’ responses didn’t slow if they were asked to name non-repeated category members like ‘pear’, or if they simply were asked to match the word given to them by the researchers.
But associative satiation can happen with all manner of sensory signals. Take for example, this optical illusion, where you are asked to focus on a centre point for a period of time. Lines move in unison towards the centre, drawing you gaze inwards. After a while, a Buddha appears in place of the moving lines and appears to be expanding outwards.
Essentially, the illusion causes your brain to disregard inward motion. When you see the Buddha, it appears as though he is expanding because the brain cells that detect outward motion win the battle against those cells that detect inwards motion (which are now tired). “The advantage here is that by satiating to inward motion, your brain is more ready to perceive outward motion," says Huber. "If there actually was outward motion, that would be something new and interesting and you’d readily perceive it.”
The visual machinery in our brain that causes this optical illusion is present in the areas of our brain that detect sounds, too. So if we repeatedly say certain words to ourselves, says Huber, the cells that detect those distinct sounds become tired. "As a result, [those brain cells] fail to activate the relevant meaning of the world.”
The next time you experience satiation in one of it’s forms, rather than thinking you are suffering from some sort of brain malfunction, be glad: In a world where we're constantly bombarded with sensory inputs, associative satiation is a technique our minds have developed to filter out what's not important. The world would be a much more confusing place if we didn’t experience it.