Bruxism of bruxism. Clenching the teeth is generally displayed by humans and other animals as a display of anger, hostility or frustration. It is thought that in humans, clenching the teeth may be an evolutionary instinct to display teeth as weapons, thereby threatening a rival or a predator. The phrase "to grit one's teeth" is the grinding or clenching of the teeth in anger, or to accept a difficult or unpleasant situation and deal with it in a determined way. In the Bible there are several references to "gnashing of teeth" in both the Old Testament, and the New Testament, where
Involuntary memory a no less valid proof for its existence during the intervening time. As more exact observation teaches us, the occurrence of these involuntary reproductions is not an entirely random and accidental one. On the contrary they are brought about through the instrumentality of other immediately present mental images. Moreover, they occur in certain regular ways that, in general terms, are described under the so-called "laws of association".' Marcel Proust was the first person to coin the term involuntary memory, in his novel "À la Recherche du Temps Perdu" ("In Search of Lost Time" or "Remembrance of Things Past"). Proust did