Science Explains The Bizarre Phenomenon Behind Why People Forget Words Mid-Sentence

The vast majority of us have at some point in our lives experienced déjà vu, the sensation that something is familiar to us even though it shouldn't be. There are in fact some other similar phenomena, including jamais vu — the opposite to déjà vu, where something familiar temporarily feels foreign — and presque vu, when you struggle to find a word mid-conversation that you would ordinarily have no issue remembering.

Most of us have been there: you are in full flow telling a totally engaging story, and then you stop, mentally reaching for a word that simply won't reveal itself. You know exactly what the word means, could easily describe it, and you know for a fact you have used it at least 6,000 times before, but in that moment, it simply slips out of your brain.

Scientists refer to this frustrating experience as the tip-of-the-tongue phenomenon, with presque vu, which translates from French as "nearly seen," describing the overall sensation of failing to remember something familiar, that feels just out of reach. This is a different situation from jamais vu, which translates as "never seen," as that refers to a situation that feels totally strange, with no familiarity even though there should be. The feeling with presque vu is that the word is familiar but is simply refusing to become fully formed.

The first thing to understand if you temporarily forget a word is that it is nothing to worry about in terms of your memory. It is usually fleeting, although you may find that the harder you struggle to pinpoint the word, the more it eludes you! Often people describe being able to "see" the first letter of the word, or even the overall structure of it, making it all the more frustrating to be so close.

If you are worried that being unable to recall a word means that your brain isn't as sharp as it used to be, you can be reassured by a study from 2014 titled "The Myth of Cognitive Decline." The authors suggest that rather than the slower processing of information as we age being due to cognitive decline, it may in fact be a result of the acquired knowledge over the years. In the same way that it would take much longer to find an item in a cupboard that is packed full than in an empty one, the brain needs to search harder in a memory that has a lifetime of facts and words in it than one that is relatively new. The study is not suggesting that learning new information is always going to lead to slower retrieval time (so there is no need to slow down your thirst for learning), but it does challenge the assumption that taking longer to recall words and information automatically means that the brain is in decline.

Some interesting research published in the Journal of Experimental Psychology: Learning, Memory, and Cognition tested two competing theories as to what causes presque vu. The "blocking" theory suggests that it happens because another, similar-sounding word gets in the way of the real word, preventing your brain from accessing it, even though the word is in there somewhere, waiting to be retrieved. For example, you could be about to say the word cardamom, and suddenly caraway seeds jump into your brain instead. They are both spices and begin with the same syllable, so caraway "blocks" the real word, cardamom from being retrieved.

The competing theory is known as the transmission deficit model, and suggests that it occurs from a weak connection between the meaning of the word, which the brain accesses first, and the sounds required to form the word. To test this theory, participants were asked to provide answers to general knowledge questions. In one case, they were first given a list of words to read aloud that, unknown to them, had similar sounds to the answers they would be looking for in the test. In the second case, they were not provided with any words in advance.

The results showed that in the cases where the participants said the answers were on the tip of their tongue, the chance of successfully retrieving the word increased as much as 50% when they had been prepped with the similar sounding words. This suggests that the transmission deficit theory could be a good explanation for experiencing presque vu, and that hearing phonologically similar words can help the brain to retrieve the correct term.