In cognitive linguistics, conceptual metaphor, or cognitive metaphor, refers to the understanding of one idea, or conceptual domain, in terms of another. An example of this is the understanding of quantity in terms of directionality (e.g. "the price of peace is rising") or the understanding of time in terms of money (e.g. "I spent time at work today").
A conceptual domain can be any mental organization of human experience. The regularity with which different languages employ the same metaphors, often perceptually based, has led to the hypothesis that the mapping between conceptual domains corresponds to neural mappings in the brain.[1][2] This theory gained wide attention in the 1990s and early 2000s, although some researchers question its empirical accuracy.[3]
The conceptual metaphor theory proposed by George Lakoff and his colleagues arose from linguistics but became of interest to cognitive scientists due to its claims about the mind and the brain. The empirical evidence for the theory has been mixed to negative. While it is generally agreed that metaphors form an important part of human verbal conceptualization, there is little support for the more specific claims that are relevant to this particular theory of metaphor comprehension.[4]
Crucially, Lakoff asserts that human thinking works effortlessly thanks to metaphorical thinking, but psychological research has found that metaphors are actually more difficult to process than non-metaphoric expressions. Furthermore, when metaphors lose their novelty and become conventionalized, they eventually lose their status of being metaphors and become processed like ordinary words (a process called grammaticalization). Therefore, the role of the conceptual metaphor in organizing human thinking is more limited than what was claimed by the linguists.[4]