What is a tip-of-the-tongue experience?
The tip-of-the-tongue experience (TOT) is characterized by being able to retrieve quite a lot of information about the target word without being able to retrieve the word itself. You know the meaning of the word. You may know how many syllables the word has, or its initial sound or letter. But you can’t retrieve it all. The experience is coupled with a strong feeling (this is the frustrating part) that you know the word, and that it is hovering on the edges of your thought.
When you do eventually remember it, the experience is often as erratic and abrupt as the initial failure — typically it pops up sometime later, when you have stopped searching for it.
Another characteristic of TOTs is that a similar sounding word keeps blocking the way. There you are, trying to remember Velcro, and all you can think of is helmet. You feel strongly that if you could just stop thinking of helmet, then you’d find the word you’re looking for, but helmet won’t budge.
What causes TOTs?
It has been thought that these interfering words cause the TOTs, but some researchers now believe they’re a consequence rather than a cause. Because you have part of the sounds of the word you’re searching for, your hard-working brain, searching for words that have those sounds, keeps coming up with the same, wrong, words.
A recent study by Dr Lori James of the University of California and Dr Deborah Burke of Pomona College suggests a different cause.
How are words held in memory? A lot of emphasis has been placed on the importance of semantic information — the meaning of words. But it may be that the sound of a word is as important as its meaning.
Words contain several types of information, including:
- semantic information (meaning),
- lexical information (letters), and
- phonological information (sound).
These types of information are held in separate parts of memory. They are connected of course, so that when, for example, you read Velcro, the letter information triggers the connected sound information and the connected meaning information, telling you how to pronounce the word and what it means.
When you try to think of a word, as opposed to being given it, you generally start with the meaning (“that sticky stuff that has fuzz on one side and tiny hooks on the other”). If the connection between that meaning and the sound information is not strong enough, the sound information won’t be activated strongly enough to allow you to retrieve all of it.
Drs James and Burke think that TOTs occur because of weak connections between the meaning and the sound of a word.
Connections are strengthened when they’re used a lot. They are also stronger when they’ve just been used. If you haven’t used a connection for a while, it will weaken. It may also be that aging weakens connections.
This may explain why the errant word suddenly “pops up”. It may be that you have experienced a similar sound to the target word.
Are TOTs worth worrying about?
TOTs are ranked by older adults as their most annoying memory failure. They do happen more often as you age, and this increase starts as early as the mid-thirties.
While everyone has TOTs, there are some differences in the TOTs experienced by older adults. For example, the most common type of word involved in TOTs at all ages is proper names. But while forgetting proper names and object names becomes more common as we get older, abstract words are actually forgotten less.
The length of time before the missing word is recalled also increases with age. This may be because older people are less likely to actively pursue a missing word, and more inclined to simply relax and think about something else. Older adults are also more likely than younger adults to go completely blank (unable to recall any part of the word’s sound or letters).
Alzheimer’s disease is characterized by word failures. However, normal TOTs tend to involve rarely used words. In Alzheimer’s, people lose very high frequency words, such as fork and spoon.
Why do TOTs increase as we age? Part of the reason may be that most of us experience fewer new and rare words as we get older and stuck in our own particular ruts. It seems that we need a lot of activation of the sound connections to keep them alive. The more we limit our experience to the tried and true, the less opportunity to keep these rarer connections active.
Dr James suggests: "People should keep using language, keep reading, keep doing crosswords. The more you use your language and encounter new words, the better your chances are going to be of maintaining those words, both in comprehension and in production, as you get older."