Lexical semantic change induced by metaphor is a cognitively and lexically economic process: complex subject matters are verbalized concisely without a new lexeme being invented. A perfect example to illustrate the process of semantic innovation and lexicalization is the naming of a ‘small, hand-guided electronic device for executing commands in computer programs’ which we today know as mouse (Blank 1999: 71, 2001: 71ff.). According to Blank (2001: 73) the process of innovation and lexicalization takes place in three steps: The first step is the association process. In the example above two concepts are associated with each other on the basis of visual similarity. This is only possible provided that one of the two concepts has already been lexicalized. This example is obviously a one-shot image metaphor: The image of a mouse is superimposed on the image of this very electronic device. Both are small, round and grey and even the wire, connecting the electronic device with the computer, reminds us of the mouse’s tail. The second step is the innovation process which means that the denotation of the already lexicalized item is assigned to the newly associated concept. The electronic device is verbalized through the lexical item mouse. The last step describes the process of both, known and new concept, being subsumed under the same denotation (Dirven 1985: 89). The one lexeme mouse corresponds to two lexicalized meanings or units: ‘little rodent’ and ‘small, hand-guided electronic device for executing commands in computer programs’. At first realized by a small group of speakers this newly innovated meaning spreads into everyday talk. Not only the English common language adopted this new meaning: The resemblance between these two concepts is so evident and convincing that it is universally understood. In turn the new meaning has also been lexicalized in other languages: ger. Maus, fr. souris, etc. Therefore the term mouse ‘electronic device’ can be defined as a universalism (Blank 2001: 71, 1999: 62). Again, this example proves that economic and efficient terms, like metaphors, are more likely to gain acceptance and be lexicalized: the non-metaphorical equivalent computer pointing device is neither economic nor efficient due its length and abstractness and would probably never gain the same (cross-cultural) acceptance as the metaphor mouse which is cognitively optimally processable due to the visual image it is based on. Moreover, the metaphor mouse meets the indented subject matter more precisely since the metaphor only highlights relevant aspects (Bründl 2001: 23, Gévaudan 2007: 99). The transfer of a perceived similarity into a linguistic form (a metaphor) is a creative process in two respects: Firstly, perceiving similarities on the cognitive level, and secondly, the transfer of this cognitive concept into a lexeme metaphor (Bründl 2001: 22, Nöth 1985: 12). As a result the semantic innovation leads to a polysemous lexeme and “polysemy is an essential condition of its [the language’s, LJ] efficiency” (Ullmann 1983: 168). The transfer or mapping that determines the connection of two completely different domains is also named “Kippeffekt”. This term also derives from the field of Gestalt psychology. It literally illustrates the process of metaphorization because it gives us a visual image of shifting an image, semantic features or a whole structure from one concept onto another (Blank 2001: 74f.).
The variety hackers’ jargon offers an analogical extension to mouse: a wireless mouse is called hamster, because it depicts a tailless mouse. In turn, this might lead to a conceptual metaphor like computer pointing devices are little rodents.
 Denotational change refers to a gradual loss of motivation and the beginning arbitrariness due to a change of the denotatum (Lipka 1992: 105-06). Concerning mouse a partial denotational change is observable: modern computer mice are related to hands, feet or paws (Bründl 2001: 171).
 Koch (1994: 213, emphasis in original) explains: „Ein prägnantes Merkmal (auf dem die Similarität beruht) tritt durch die Interaktion zwischen einem Herkunftsdesignat und einem […] Zieldesignat hervor, und zwar derart, daß in einer Art Kippeffekt das Zieldesignat auf Grund prägnanter Merkmale als das Herkunftsdesignat gesehen wird.“
Blank, Andreas. 1999. Why Do New Meanins Occur? A Cognitive Typology of the Motivations for Lexical Semantic Change. Historical Semantics and Cognition, Peter Koch & Andreas Blank (Eds), 61-89. Berlin: de Gruyter.
Blank, Andreas. 2001. Einführung in die lexikalische Semantik für Romanisten. Tübingen: Niemeyer.
Bründl, Monika E. 2001. Lexikalische Dynamik: Kognitiv-linguistische Untersuchungen am englischen Computerwortschatz. Tübingen: Niemeyer.
Dirven, René. 1985. Metaphor as Basic Means for Extending the Lexicon. The Ubiquity of Metaphor, Paprotté & Dirven (Eds), 85-119.
Gévaudan, Paul. 2007. Typologie des lexikalischen Bedeutungswandels. Bedeutungswandel, Wortbildung und Entlehnung am Beispiel der romanischen Sprachen. Tübingen: Stauffenberg Linguistik.
Nöth, Winfried. 1985. Semiotic Aspects of Metaphor. The Ubiquity of Metaphor, Paprotté & Dirven (Eds), 1-16.
Ullmann, Stephen. 1983. Semantics: An Introduction to the Science of Meaning. Oxford: Blackwell.