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You know that feeling, when you know a word but it’s just out of reach, stuck on the tip of your tongue? Well, why does it happen? And what can you do about it?

Hosted by: Hank Green
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[intro plays]

Hank: We all know it: the intense frustration, the self-loathing when a word is stuck right on the tip of your tongue. Researchers have been studying this phenomenon since the 1960's hoping for some relief and finally, thanks to science, we have salvation. The words presque vu meaning almost seen describe that thing where you can almost say a word, you're positive you know it, and if I just give you like have a second you'd be able to say it but no, you totally never get it. And the french term provides a nice dose of always appreciated culture and I use it because the English one... doesn't exist, not cuz I can't think of it, we just don't have a word for it.

According to researchers, tip of the tongue states or TOTS happen all the time, an infuriating once a week for most of us which increases to about once daily as we get age. They span most languages, from Arabic to Afrikaans and in the worst cases, they're accompanies by blockers or so-called "ugly sisters," like when you're trying to think of Van Gogh and all you can think of is Vin Diesel.

To understand Tip of the Tongue states, scientists combined theories in neuroscience and computer science into what's known as connectionist models. These describe the ways we can use computers to simulate how neurons in our brains handle language. In these models, the brain is represented as a network of connected nodes, processing centers that are kinda like individual computers.

Even though the connectionist models describe things in terms of networks and nodes, they're a lot like the way our brains actually work. In 1949, a psychologist names Donald Hebb proposed a theory to explain how neurons in the brain change through experience to encode new information. It's how we learn. In both connectionist models and neuroscience, as you have a thought, particular clusters of neurons or nodes are activated, meaning they start sending signals to each other. Activation then spreads from higher, more complex clusters to lower ones in patterns that seem unpredictable at first but after a while, it's not unpredictable at all. Activating certain cluster when you have a thought actually physically changes the connections between them making it more likely they'll activate together again. It's like a path in the woods, the more it's used, the more defined the path gets.

And while learning is all well and good, it doesn't mean much if you can't cough up all the know-y good stuff when it comes time to. Retrieving the knowledge starts at the highest level of clusters, the one containing semantic or meaning information. Then, the activation spreads down to the lowest level clusters contained phonological or sound information.

So say you want to talk about King Arthur's sword. First, a higher level cluster would light up and that would spread down to the clusters for each sound in Excalibur. A tip of the tongue state is what happens when the meaning clusters light up, but the sound clusters don't activate completely, because the signal in your brain takes a detour instead of following the right path. That's why you can often describe characteristics of the word and not the whole word itself. It's like "it starts with S, or rhymes with snorts-en-bagger" when you're trying to remember who played the Terminator, actually I was playing a game with my mom recently and she was trying to think of Uma Thurman and she said Urna Thulman. Which... I'm never gonna let her live that down.

And as it turns out, having someone tell you the word is probably doing more harm than good. In something the researchers call the resolution effect, coming to the word yourself makes it more likely that your brain will reinforce the correct pathway from meaning to sound activation. So the next time someone asks you to help them with a word you might want to look them in the eye and say "NO! You're never gonna learn that way!"

But there are other ways to help them. Researchers found that giving a person in a TOT state a hint about the word, for example like "Arn..." if you're goin for Arnold Schwarzenegger, helps establish the right connections in their brain. And then next time it'll be easier for them to come up with the word or the person's name on their own.

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