This condition is so common that its the names he has in almost all languages. In English we call it "On the tip of my tongue" or "on the tip of my tongue".
Despite its prevalence and obvious antiquity — time this phenomenon found in many languages — scientists know about him quite a bit. The problem is that it is relatively rare, it is impossible to cause knowingly and on purpose. How to study? However, there was still persistent enough people who conducted a series relevant studies.
So what causes the phenomenon of "on the tip of my tongue"?
The translation of thoughts into words is a complex process that we take for granted mainly because most people have it happen automatically. However, this is difficult. Brain needs to transform abstract concepts into words, and then another, and convert them into sounds.
In the case of the existence of the phenomenon of "on the tip of my tongue", somewhere in this mechanism fails. Where exactly are scientists reliably't know until now. Some say that the problem in the vocal apparatus, the others nodding in remembrance. Still others say they don't know what causes it, but realized that he promotes: lots of caffeine, little sleep, and fatigue.
Eventually scientists decided to conduct the following test. They asked a group of subjects to tell them what the name of the activity for the exploration of the caves. If people remembered right, he was withdrawn from the study — the researchers were only interested in those who "knew, but forgot" (incidentally, the word "spelunking").
The researchers gave them some time to recall, and then called the correct answer. After that, they at varying intervals, from 5 minutes to several weeks, asking the same question again. As there is the activity for the exploration of the caves?
It turned out that if people are told the correct answer, they immediately forgot. And Yes, they could not answer even after five minutes. This gave grounds to speak about the fact that when we try to recall a forgotten word using dictionaries or the Internet, we doom ourselves to again forget it. Apparently, the brain does not appreciate" the fact that he gets too easy.
How to protect against the phenomenon of "on the tip of my tongue"?
Because scientists don't know what it exactly called, credible answer to this question is no. However, it is quite clear that in order to not become a victim of the phenomenon in relation to the same word again (and again), it is necessary to remember the word itself, and not to go to the Internet. The study they found that when people give the answer, his brain not activate the same brain areas that are activated when it is finally! — he remembers the word. That is, even physiologically "recalled himself" and "prompted" are fundamentally different processes.
You can even ask others for help, but you don't let them say the whole word, and give clues like "starts with "C" (by the Way, not peeping above — what's the name of the activity for the exploration of the caves? Huh?!). It seems that the brain that's sufficient to be considered "remembering" their victory and not to forget the search word in five minutes.
What practical advice to "specifically recall "lost" word?!", there is nothing better than a good old-fashioned advice: "stop thinking about him". It really works. And, Yes, meaningful attempts to recollect, on the contrary, make it worse. Scientists checked.